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Inconel(From Wikipedia)

2011-01-16T19:21:00.000-08:00

Inconel is a registered trademark of Special Metals Corporation that refers to a family of austenitic nickel-chromium-based superalloys.[1] Inconel alloys are typically used in high temperature applications. It is often referred to in English as "Inco" (or occasionally "Iconel"). Common trade names for Inconel include: Inconel 625, Chronin 625, Altemp 625, Haynes 625, Nickelvac 625 and Nicrofer 6020.[2]

Composition

Different Inconels have widely varying compositions, but all are predominantly nickel, with chromium as the second element.

Properties

Inconel alloys are oxidation and corrosion resistant materials well suited for service in extreme environments. When heated, Inconel forms a thick, stable, passivating oxide layer protecting the surface from further attack. Inconel retains strength over a wide temperature range, attractive for high temperature applications where aluminum and steel would succumb to creep as a result of thermally-induced crystal vacancies (see Arrhenius equation). Inconel's high temperature strength is developed by solid solution strengthening or precipitation strengthening, depending on the alloy. In age hardening or precipitation strengthening varieties, small amounts of niobium combine with nickel to form the intermetallic compound Ni3Nb or gamma prime (γ'). Gamma prime forms small cubic crystals that inhibit slip and creep effectively at elevated temperatures.

Machining

Inconel is a difficult metal to shape and machine using traditional techniques due to rapid work hardening. After the first machining pass, work hardening tends to plastically deform either the workpiece or the tool on subsequent passes. For this reason, age-hardened Inconels such as 718 are machined using an aggressive but slow cut with a hard tool, minimizing the number of passes required. Alternatively, the majority of the machining can be performed with the workpiece in a solutionised form, with only the final steps being performed after age-hardening. External threads are machined using a lathe to "single point" the threads, or by rolling the threads using a screw machine. Holes with internal threads are made by welding or brazing threaded inserts made of stainless steel. Cutting of plate is often done with a waterjet cutter. Internal threads can also be cut by single point method on lathe, or by threadmilling on a machining center. New whisker reinforced ceramic cutters are also used to machine nickel alloys. They remove material at a rate typically 8 times faster than carbide cutters. 718 Inconel can also be roll threaded after full aging by using induction heat to 1300 degrees F without increasing grain size.[citation needed]

Joining

Welding inconel alloys is difficult due to cracking and microstructural segregation of alloying elements in the heat affected zone. However, several alloys have been designed to overcome these problems. The most common welding method is gas tungsten arc welding.[7]
New innovations in pulsed micro laser welding have also become more popular in recent years.

Uses

Inconel is often encountered in extreme environments. It is common in gas turbine blades, seals, and combustors, as well as turbocharger rotors and seals, electric submersible well pump motor shafts, high temperature fasteners, chemical processing and pressure vessels, heat exchanger tubing, steam generators in nuclear pressurized water reactors, natural gas processing with contaminants such as H2S and CO2, firearm sound suppressor blast baffles, and Formula One and NASCAR exhaust systems.[8][9] Inconel is increasingly used in the boilers of waste incinerators.[10] The Joint European Torus vessel is made in Inconel.[11] Inside JET a plasma is heated to temperatures that are higher than those found in the Sun. A strong magnetic field keeps the plasma away from the vessel.

North American Aviation constructed the skin of the X-15 rocket plane out of an Inconel alloy known as "Inconel X".[12]
Rolled Inconel was frequently used as the recording medium by engraving in Black Box recorders on aircraft[13]
Alternatives to the use of Inconel in chemical applications like scrubber, columns, reactors, and pipes is Hastelloy, perfluoroalkoxy (PFA) lined carbon steel or fiber reinforced plastic.

Inconel alloys

Inconel 600: Solid solution strengthened

Inconel 625: Acid resistant, good weldability
Inconel 690: Low cobalt content for nuclear applications, and low resistivity[14]
Inconel 718: Gamma double prime strengthened with good weldability
Inconel 751: Increased aluminum content for improved rupture strength in the 1600°F range[15]
Inconel 939: Gamma prime strengthened with good weldability

Extraction and separation technology of aniseed shikimic acid(專利)

2009-03-08T20:30:00.001-07:00

Extraction and separation technology of aniseed shikimic acid

Patent Number(s): CN100999461-A
Inventor(s): MIN Y, LIU W, YANG J
Patent Assignee(s) and Codes(s):HONGHE INST (HONG-Non-standard)
Derwent Primary Accession Number: 2008-A50137 [04]
Abstract: NOVELTY - The invention claims an extraction and separation technology of aniseed shikimic acid. Its main steps are to degrease the dry crashed aniseed at 40~45 centigrade, 25~35 MPa through supercritical carbon dioxide to get edible flavor; leaching extract by heating and refluxing at 50~60 centigrade through carbinol after degreasing; extracting at 50~55 centigrade through ethyl acetate and then filtering and separating ethyl acetate to get solid extract; adding carbinol at 50~60 centigrade, heating and churning up until extract dissolves and then filtering, placing the filtered liquid still and cooling to get crystal-the coarse shikimic acid; dissolving the coarse shikimic acid at 45~50 centigrade through mixed solvent of chloroform and carbinol, placing naturally, cooling crystal and then purifying to get purified product, whose purity is larger than 95%. The invention adopts supercritical carbon dioxide to degrease, so that the aniseed oil can be used as flavor and can be eaten directly, it has no harm to human body. This technology improves the use of aniseed, improves degreasing efficiency and reduces the effect of liposoluble ingredients to the later operation so that it improves the recovery rate.
Show Documentation Abstract
International Patent Classification: A61K-036/185; A61K-036/57; A61K-131/00; C07C-051/42; C07C-062/00; C07C-062/04
Derwent Class Code(s): B04 ; B05
Derwent Manual Code(s): B04-A08C2; B04-B01C1; B10-C04A; B11-B03
Patent Details:
Patent Number
Publ. Date
Main IPC
Week
Page Count
Language
CN100999461-A
18 Jul 2007
C07C-051/42
200804

Application Details:
CN100999461-A
CN10065617
13 Jan 2007
Priority Application Information and Date:
CN10065617
13 Jan 2007

膠原蛋白

2009-03-04T00:58:00.001-08:00

膠原蛋白是人體的一種非常重要的蛋白質，主要存在於結締組織中。它具有很強的伸張能力，是韌帶和肌鍵的主要成份，膠原蛋白還是細胞外基質的主要組成成分。它使皮膚保持彈性，而膠原蛋白的老化，則使皮膚出現皺紋。膠原蛋白亦是眼睛角膜的主要成份，但以結晶形式組成。
構成膠原的肽鏈，其胺基酸序列非常有特色。首先，它富含甘氨酸和脯氨酸殘基，前者的含量達到總胺基酸殘基的1/3後者則接近1/4；其次，序列中含有不由DNA 鹼基三聯密碼子編碼的羥賴氨酸和羥脯氨酸，這兩種胺基酸是在蛋白質一級結構序列形成之後由特定的酶作用於序列中的賴氨酸和脯氨酸形成的；最後，它的序列中只含有很少的酪氨酸殘基;並且不含有色氨酸和半胱氨酸殘基。膠原蛋白一級結構的另一個特點是它的胺基酸的排列。這些胺基酸一般以-甘氨酸-脯氨酸-羥脯氨酸-三聯交替出現的順序排列。只有很少的蛋白質有這樣規則的胺基酸排列。
在空間結構上，膠原蛋白顯示出特殊的三股螺旋纏繞的結構，三條相互獨立的膠原蛋白肽鏈依靠甘氨酸之間形成的氫鍵維繫三股螺旋相互纏繞的結構。膠原蛋白肽鏈的三股螺旋結構不同於普通的α螺旋結構，它的螺距更大，但每一圈螺旋所包含的胺基酸殘基數卻很小，僅為3.3個，因此膠原蛋白的三股螺旋顯得細而長，螺旋中間的空間很小，僅能容納一個氫原子，只有甘氨酸能夠勝任這個位置。另外脯氨酸所特有的肽平面夾角也是形成這種特殊螺旋結構的必須因素。這也是膠原蛋白肽鏈中-甘氨酸-脯氨酸-羥脯氨酸-三聯序列交替出現的原因。膠原蛋白這種特殊的三股螺旋結構保證了它的機械強度。這種三股螺旋被稱為原膠原。
若干個原膠原橫向堆積，序列中所含有的羥賴氨酸和羥脯氨酸側鏈在酶作用下氧化生成醛，相互之前發生羥醛縮合反應形成原膠原之間的共價連結，這種結構被稱為膠原微纖維。許多膠原微纖維橫向堆積，以相同的方式通過共價鍵連結，形成膠原纖維。膠原纖維是膠原蛋白行使生理作用的基本形態，在生物體內膠原纖維交織成富有機械強度合彈性的網狀結構成為結締組織最基本的組成成分。
目前膠原蛋白是非常受到歡迎的保健美容品，使用範圍以整型醫學、營養輔助品、保養品為三大主流，也就是以注射、口服、擦拭為應用。
而其中以注射效果最好但價格昂貴，擦拭則因分子量太大而無法吸收，因此目前較為熱門的是水解過的口服膠原蛋白，不但價格適中且效果好，市面上知名的有台鹽、珍寶三旺、芳珂、金牌、白蘭氏，注射的則有雙美等廠商。
事實上口服的膠原蛋白會受到胃酸破壞，無法吸收，所以口服的膠原蛋白其實對於皮膚的幫助不大，想要皮膚能夠產生膠原蛋白的話，就必須要刺激皮膚表面，讓身體自行生成膠原蛋白，才會有效，目前來說，塗抹左旋Ｃ是副作用最小的方式。
但也有說法指出膠原蛋白是品質較差的蛋白質來源，因為它們沒有全部的必需胺基酸-也就是說它們並不是完全蛋白質(complete protein)。業者聲稱口服膠原蛋白食品能達到改善皮膚、指甲或關節的美容保健功效，但是這個說法並沒有得到任何主流研究結果的支持。通常這些部位有問題的人，比較有可能是因為其他因素造成的，而不是因為飲食中缺乏蛋白質的關係。就算是因為缺乏蛋白質的緣故，蛋白質也能夠由其他較佳的食物來源獲得。
http://zh.wikipedia.org/wiki/%E8%86%A0%E5%8E%9F%E8%9B%8B%E7%99%BD

冷壓油

2009-03-04T00:42:00.001-08:00

揭開冷壓油的神秘面紗www.sesameoil.com.tw
揭開冷壓油的神秘面紗元福麻油廠www.sesameoil.com.tw隨著健康概念的興起，近來各種食材也吹起養生風，平日與大家息息相關的食用油也不例外，因此，”冷壓油”成了時髦的火紅商品，然而, 究竟何謂冷壓油？有何益處？有何差別？相信這是許多人心中共同的疑問本文將針對此議題深入探討之。傳統的煉油術不外乎以下五種方式：
一. 南方壓榨法（中國傳統製油法）流程：篩選清洗→烘焙翻炒→磨碎 →壓榨 → 靜置 → 第一次過濾 → 精密過濾 → 靜置沈澱 → 裝瓶1. 篩選清洗：去除砂土、塵埃、枝葉…等雜質異物。2. 烘焙翻炒：蒸發原料含的水份，以烘焙產生油品特有香味。3. 磨碎：破壞原料細胞膜，以促進提油之製程。4. 壓榨：利用自動化機械壓榨油脂。5. 靜置沈澱：放置於沉澱桶中使雜質沉澱。6. 過濾：去除油中之殘餘雜質，使油品純粹。 7. 7. 裝瓶 : 裝入消毒後之瓶子。二. 北方水洗法（中國傳統製油法）生產方式是原料經過烘培、磨醬、用熱水均勻快速攪拌後，置於鍋中旋動讓油浮出表面，取油靜置，再過濾而成。其原理是利用油和水的不同比重，水被原料中的親水物質吸收而取代出油，油浮在表面，相當於油經過了“水洗”過程而去掉了雜質和異味，整個過程稱之為水洗法。三. 溶劑法油是利用溶劑將油萃取出來，再將溶劑蒸發，剩下油的部份，這樣的產率就比傳統用擠壓的方式還高。但是某些維生素可能會因蒸發時的加熱而破壞。四. 連續式螺旋壓榨法使用連續式螺旋壓榨的時期比水壓式晚，典型的連續螺旋壓榨須具備兩個條件，1.需有充足的原料貯量以供應機械持續操作，避免提油中斷。2.需先除去原料中的雜質、砂粒，避免影響油脂品質與油粕成份，並減少機械摩擦損耗。一般螺旋壓榨的原料處理，可分為去皮殼與保留皮殼兩種，螺旋壓榨前須先將油籽原料翻動或捏碎果實，以便打破其均勻而堅實的細胞壁，增加提油效率，更使原料蒸煮均勻以提高油脂品質。五.水壓式壓榨法本法通常應用在批式壓榨，是最古老的提油方式之一，其原理是利用水之壓力搾出原料中之油脂。水壓式壓榨可分為開放式與密閉式兩種，兩種方式之區別在於開放式僅需將含油原料裹固在壓榨布袋內即可，而密閉式則除布袋裹固原料外，還加一成密閉箱。開放式又分板式與箱式兩種，板式壓榨法是將裹有原料之布袋至於板面之間，而在其板面上加上凸起之皺摺紋路或鋪上一層毛墊以便於油之流動與排出。箱式壓榨乃將原料直接放入其長方形的箱式壓榨盒中，免去了濾袋包裹原料的麻煩（其盒子底部之表面是以摺狀多孔之格架形式組成，而上層板面則呈角形，板面由上往下壓，搾出之油流到底部，在排出收集。密閉式壓榨使用具有多孔之鋼製容器，將原料裝載固定在裡面，因此節省許多使用濾布壓榨的麻煩，此外，就使用之壓力而言，密閉式比開放式高，亦即密閉式壓榨可以得到較高的榨油率。
而所謂的冷壓法即是採取第一種技術-壓榨法，在”烘焙翻炒”這個步驟，有低溫、中溫與高溫三種，一般製油廠會憑藉其經驗，來決定烘炒的溫度與時間。而所謂的冷壓，是以小火焙炒，經過磨碎，低溫壓榨萃取油、過濾、靜置、再過濾後充填包,過程其實與傳統方式大同小異，只是溫度控制的較低而已，所以，有標榜冷壓的油，就是在強調其富含維生素，而且沒有溶劑殘留的疑慮。
附錄【麻油相關文獻】胡麻油，即芝麻油。漢使張騫始自大宛得油麻種來，故名「胡麻」。胡麻自古常用為滋補、補肝腎、補肺、潤五臟，堅筋骨、添精髓、明耳目、烏髭髮，逐風濕氣。民間世俗最常用於坐月子，產婦滋養，食補首選「麻油雞」。對於產後諸虛提供熱量來源，驅風（產婦生產時，氣血大量流失，血虛氣虛最易招風）益肝，養血益精，益氣力、潤燥、通便、潤腸、堅筋骨。胡麻油熬膏外敷，能滋養、潤滑表皮細胞、涼血、解毒、療瘡、生肌止痛。【苦茶油相關文獻】苦茶油含有豐富之蛋白質、維生素A、E等，其營養價值及對高溫的安定性均優與於黃豆油，甚至可與橄欖油相媲美。苦茶油更是單元不飽和脂肪酸含量最豐富之食用油，不僅對降低血中膽固醇、預防心血管疾病有很大的功效，根據研究顯示，其單元不飽和脂肪酸主要由油酸(Oleic Acid)、亞油酸(Linoleic Acid)組成，加熱時不易產生油煙，具相當的穩定，性質接近橄欖油。另苦茶油含有豐富的山茶柑素，可潤肺、清肝解毒、整腸健胃等營養價值高，為一健康之高級食用油。根據研究顯示，幽門螺旋桿(Helicobacter pylori)會引起胃潰瘍、消化不良及十二指腸潰瘍等消化性疾病，而高達85%~90%之潰瘍疾病都與幽門螺旋桿菌之感染有關。國科會專題研究「苦茶油抗菌因素研究(Study on antimicrobial factors of Camellia oil)*」(86年5月)，結論是苦茶油及苦茶渣之萃取及純化物對幽門螺旋桿菌具有抗菌作用，證實了傳說中苦茶油對胃疾之紓緩。

綠咖啡豆萃取--綠原酸(Chlorogenic Acid)

2009-03-03T23:44:00.000-08:00

一項在歐美地區經過長達10年20多萬人數研究統計顯示，每天喝超過七杯咖啡的人比低於二杯的人，罹患第二糖尿病的機會低於50%，且血糖濃度也較低。
綠原酸(chlorlgenic Acid)存在於咖啡豆中，在未經烘培的咖啡豆中含量高達45%以上，而經過烘培的咖啡豆僅存5~10%。
綠原酸的功用
1.阻止小腸吸收葡萄糖。
2.阻止肝糖酵素釋放葡萄糖進入血液。
3.幫助脂肪燃燒，提供能量給肌肉
4.減少胰島素的需求
以上的功能可以想像，對肥胖者的幫助，能將脂肪組織燃燒掉，因此在調整BMI值有顯著的效果。在臨床試驗中，連續服用六週後，BMI值平均減少6%，肌肉/脂肪比例提升4%。
綠原酸主要存在於綠咖啡豆中，但咖啡所含的咖啡因的成癮性和對身體的危害是不容忽視。經過特殊萃取技術，能使咖啡因的含量低於2%，咖啡豆中所含有毒二萜類(會引發心血管疾病)大幅降低至2PPM以下。
資料來源：http://tw.myblog.yahoo.com/f29801235/article?mid=492&prev=509&next=481

Dibenzothiophene

2009-02-23T19:35:00.000-08:00

Dibenzothiophene
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Dibenzothiophene

IUPAC name Dibenzothiophene
Other names Diphenylene sulfide

Identifiers
CAS number 132-65-0
RTECS number HQ3490550

Properties
Molecular formula C12H8S
Molar mass 184.26 g/mol
Appearance Colourless crystals
Density ? g/cm3
Melting point 97-100 °C(lit.)
Boiling point 332-333 °C
Solubility in water insol.
Solubility in other solvents benzene and related

Hazards
Main hazards flammable
R-phrases 22
S-phrases 36

Related compounds
Related compounds Thiophene anthracene benzothiophene

Except where noted otherwise, data are given formaterials in their standard state(at 25 °C, 100 kPa)Infobox references

Dibenzothiophene is the organic compound consisting of two benzene rings fused to a central thiophene ring. This tricyclic heterocycle, and especially its alkyl substituted derivatives occur widely in heavier fractions of petroleum.
Dibenzothiophene is prepared by the reaction of biphenyl with sulfur dichloride in the presence of aluminium trichloride.

http://en.wikipedia.org/wiki/Dibenzothiophene

Hydrodesulfurization

2009-02-18T22:16:00.000-08:00

From Wikipedia, the free encyclopedia
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Hydrodesulfurization (HDS) is a catalytic chemical process widely used to remove sulfur (S) from natural gas and from refined petroleum products such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils.[1][2] The purpose of removing the sulfur is to reduce the sulfur dioxide (SO2) emissions that result from using those fuels in automotive vehicles, aircraft, railroad locomotives, ships, gas or oil burning power plants, residential and industrial furnaces, and other forms of fuel combustion.
Another important reason for removing sulfur from the naphtha streams within a petroleum refinery is that sulfur, even in extremely low concentrations, poisons the noble metal catalysts (platinum and rhenium) in the catalytic reforming units that are subsequently used to upgrade the octane rating of the naphtha streams.
The industrial hydrodesulfurization processes include facilities for the capture and removal of the resulting hydrogen sulfide (H2S) gas. In petroleum refineries, the hydrogen sulfide gas is then subsequently converted into byproduct elemental sulfur. In fact, the vast majority of the 64,000,000 metric tons of sulfur produced worldwide in 2005 was byproduct sulfur from refineries and other hydrocarbon processing plants.[3][4]
An HDS unit in the petroleum refining industry is also often also referred to as a Hydrotreater.
History
Although reactions involving catalytic hydrogenation of organic substances were known prior to 1897, the property of finely divided nickel to catalyze the fixation of hydrogen on hydrocarbon (ethylene, benzene) double bonds was discovered by the French chemist, Paul Sabatier.[5][6] Thus, he found that unsaturated hydrocarbons in the vapor phase could be converted into saturated hydrocarbons by using hydrogen and a catalytic metal. His work was the foundation of the modern catalytic hydrogenation process.
Soon after Sabatier's work, a German chemist, Wilhelm Normann, found that catalytic hydrogenation could be used to convert unsaturated fatty acids or glycerides in the liquid phase into saturated ones. He was awarded a patent in Germany in 1902[7] and in Britain in 1903,[8] which was the beginning of what is now a worldwide industry.
In the mid-1950's, the first noble metal catalytic reforming process (the Platformer process) was commercialized. At the same time, the catalytic hydrodesulfurization of the naphtha feed to such reformers was also commercialized. In the decades that followed, various proprietary catalytic hydrodesulfurization processes such as the one depicted in the flow diagram below have been commercialized. Currently, virtually all of the petroleum refineries world-wide have one or more HDS units.
By 2006 miniature microfluidic HDS units had been implemented for treating JP-8 jet fuel to produce clean feed stock for a fuel cell hydrogen reformer.[9] By 2007 this had been integrated into an operating 5kW fuel cell generation system.[10]

The process chemistry
Hydrogenation is a class of chemical reactions in which the net result is the addition of hydrogen (H). Hydrogenolysis is a type of hydrogenation and results in the cleavage of the C-X chemical bond, where C is a carbon atom and X is a sulfur, nitrogen (N) or oxygen (O) atom. The net result of a hydrogenolysis reaction is the formation of C-H and H-X chemical bonds. Thus, hydrodesulfurization is a hydrogenolysis reaction. Using ethanethiol (C2H5SH), a sulfur compound present in some petroleum products, as an example, the hydrodesulfurization reaction can be simply expressed as
Ethanethiol + Hydrogen → Ethane + Hydrogen sulfide
C2H5SH + H2 → C2H6 + H2S
For the mechanistic aspects of, and the catalysts used in this reaction see the section catalysts and mechanisms

Process description
In an industrial hydrodesulfurization unit, such as in a refinery, the hydrodesulfurization reaction takes place in a fixed-bed reactor at elevated temperatures ranging from 300 to 400 °C and elevated pressures ranging from 30 to 130 atmospheres of absolute pressure, typically in the presence of a catalyst consisting of an alumina base impregnated with cobalt and molybdenum.
The image below is a schematic depiction of the equipment and the process flow streams in a typical refinery HDS unit.

Schematic diagram of a typical Hydrodesulfurization (HDS) unit in a petroleum refinery
The liquid feed (at the bottom left in the diagram) is pumped up to the required elevated pressure and is joined by a stream of hydrogen-rich recycle gas. The resulting liquid-gas mixture is preheated by flowing through a heat exchanger. The preheated feed then flows through a fired heater where the feed mixture is totally vaporized and heated to the required elevated temperature before entering the reactor and flowing through a fixed-bed of catalyst where the hydrodesulfurization reaction takes place.
The hot reaction products are partially cooled by flowing through the heat exchanger where the reactor feed was preheated and then flows through a water-cooled heat exchanger before it flows through the pressure controller (PC) and undergoes a pressure reduction down to about 3 to 5 atmospheres. The resulting mixture of liquid and gas enters the gas separator vessel at about 35 °C and 3 to 5 atmospheres of absolute pressure.
Most of the hydrogen-rich gas from the gas separator vessel is recycle gas which is routed through an amine contactor for removal of the reaction product H2S that it contains. The H2S-free hydrogen-rich gas is then recycled back for reuse in the reactor section. Any excess gas from the gas separator vessel joins the sour gas from the stripping of the reaction product liquid.
The liquid from the gas separator vessel is routed through a reboiled stripper distillation tower. The bottoms product from the stripper is the final desulfurized liquid product from hydrodesulfurization unit.
The overhead sour gas from the stripper contains hydrogen, methane, ethane, hydrogen sulfide, propane and perhaps some butane and heavier components. That sour gas is sent to the refinery's central gas processing plant for removal of the hydrogen sulfide in the refinery's main amine gas treating unit and through a series of distillation towers for recovery of propane, butane and pentane or heavier components. The residual hydrogen, methane, ethane and some propane is used as refinery fuel gas. The hydrogen sulfide removed and recovered by the amine gas treating unit is subsequently converted to elemental sulfur in a Claus process unit.
Note that the above description assumes that the HDS unit feed contains no olefins. If the feed does contain olefins (for example, the feed is a naphtha derived from a refinery fluid catalytic cracker (FCC) unit), then the overhead gas from the HDS stripper may also contain some ethene, propene, butenes and pentenes or heavier components.
It should also be noted that the amine solution to and from the recycle gas contactor comes from and is returned to the refinery's main amine gas treating unit.

Sulfur compounds in refinery HDS feedstocks
The refinery HDS feedstocks (naphtha, kerosene, diesel oil and heavier oils) contain a wide range of organic sulfur compounds, including thiols, thiophenes, organic sulfides and disulfides, and many others. These organic sulfur compounds are products of the degradation of sulfur containing biological components, present during the natural formation of the fossil fuel, petroleum crude oil.
When the HDS process is used to desulfurize a refinery naphtha, it is necessary to remove the total sulfur down to the parts per million range or lower in order to prevent poisoning the noble metal catalysts in the subsequent catalytic reforming of the naphthas.
When the process is used for desulfurizing diesel oils, the latest environmental regulations in the United States and Europe, requiring what is referred to as ultra-low sulfur diesel (ULSD), in turn requires that very deep hydrodesulfurization is needed. In the very early 2000's, the governmental regulatory limits for highway vehicle diesel was within the range of 300 to 500 ppm by weight of total sulfur. As of 2006, the total sulfur limit for highway diesel is in the range of 15 to 30 ppm by weight.[11]

Thiophenes
A family of substrates that are particularly common in petroleum are the aromatic sulfur-containing heterocycles called thiophenes. Many kinds of thiophenes occur in petroleum ranging from thiophene itself to more condensed derivatives called benzothiophenes and dibenzothiophenes. Thiophene itself and its alkyl derivatives are easier to hydrogenolyse, whereas dibenzothiophene, especially its 4,6-disubstituted derivatives, are considered the most challenging substrates. Benzothiophenes are midway between the simple thiophenes and dibenzothiophenes in their susceptibility to HDS.

Catalysts and mechanisms
The main HDS catalysts are based on MoS2 together with smaller amounts of other metals.[12] The nature of the sites of catalytic activity remains an active area of investigation, but it is generally assumed basal planes of the MoS2 structure are not relevant to catalysis, rather the edges or rims of these sheet.[13] At the edges of the MoS2 crystallites, the molybdenum centre can stabilize a coordinatively unsaturated site (CUS), also known as an anion vacancy. Substrates, such as thiophene, bind to this site and undergo a series a reactions that result in both C-S scission and C=C hydrogenation. Thus, the hydrogen serves multiple roles - generation of anion vacancy by removal of sulfide, hydrogenation, and hydrogenolysis. A simplified diagram for the cycle is shown:

Simplified diagram of a HDS cycle for thiophene

Catalysts
Most metals catalyse HDS, but it is those at the middle of the transition metal series that are most active. Ruthenium disulfide appears to be the single most active catalyst, but binary combinations of cobalt and molybdenum are also highly active.[14] Aside from the basic cobalt-modified MoS2 catalyst, nickel and tungsten are also used, depending on the nature of the feed. For example, Ni-W catalysts are more effective for hydrodenitrification (HDN).

Supports
Metal sulfides are "supported" on materials with high surface areas. A typical support for HDS catalyst is γ-alumina. The support allows the more expensive catalyst to be more widely distributed, giving rise to a larger fraction of the MoS2 that is catalytically active. The interaction between the support and the catalyst is an area of intense interest, since the support is often not fully inert but participates in the catalysis.

Other uses
The basic hydrogenolysis reaction has a number of uses other than hydrodesulfurization.

Hydrodenitrogenation
The hydrogenolysis reaction is also used to reduce the nitrogen content of a petroleum stream and, in that case, is referred to Hydrodenitrogenation (HDN). The process flow scheme is the same as for an HDS unit.
Using pyridine (C5H5N), a nitrogen compound present in some petroleum fractionation products, as an example, the hydrodenitrogenation reaction has been postulated as occurring in three steps:[15][16]
Pyridine + Hydrogen → Piperdine + Hydrogen → Amylamine + Hydrogen → Pentane + Ammonia
C5H5N + 5H2 → C5H11N + 2H2 → C5H11NH2 + H2 → C5H12 + NH3
and the overall reaction may be simply expressed as:
Pyridine + Hydrogen → Pentane + Ammonia
C5H5N + 5H2 → C5H12 + NH3
Many HDS units for desulfurizing naphthas within petroleum refineries are actually simultaneously denitrogenating to some extent as well.

Saturation of olefins
The hydrogenolysis reaction may also be used to saturate or convert olefins (alkenes) into paraffins (alkanes). The process used is the same as for an HDS unit.
As an example, the saturation of the olefin, pentene, can be simply expressed as:
Pentene + Hydrogen → Pentane
C5H10 + H2 → C5H12
Some hydrogenolysis units within a petroleum refinery or a petrochemical plant may be used solely for the saturation of olefins or they may be used for simultaneously desulfurizing as well as denitrogenating and saturating olefins to some extent.

Hydrogenation in the food industry
Further information: Hydrogenation, Wilhelm Normann, and Trans fat
The food industry uses hydrogenation to completely or partially saturate the unsaturated fatty acids in liquid vegetable fats and oils to convert them into solid or semi-solid fats, such as those in margarine and shortening.

Desulfurization technology research
Hundreds of research publications appear annually on HDS technologies. Illustrative of the range of ideas being discussed are reports on ultrasonically assisted desulfurization.[17]

See also
Timeline of hydrogen technologies

References
^ Gary, J.H. and Handwerk, G.E. (1984). Petroleum Refining Technology and Economics (2nd Edition ed.). Marcel Dekker, Inc. ISBN 0-8247-7150-8.
^ Hydrodesulfurization Technologies and Costs Nancy Yamaguchi, Trans Energy Associates, William and Flora Hewlett Foundation Sulfur Workshop, Mexico City, May 29-30, 2003
^ Sulfur production report by the United States Geological Survey
^ Discussion of recovered byproduct sulfur
^ C.R.Acad.Sci. 1897, 132, 210
^ C.R.Acad.Sci. 1901, 132, 210
^ DE Patent DE141029 (Espacenet, record not available)
^ UK Patent GB190301515 GB190301515 (Espacenet)
^ Microchannel HDS (March 2006)
^ Fuel cells help make noisy, hot generators a thing of the past (December 2007) Pacific Northwest National Laboratory
^ Diesel Sulfur published online by the National Petrochemical & Refiners Association (NPRA)
^ Topsøe, H.; Clausen, B. S.; Massoth, F. E., Hydrotreating Catalysis, Science and Technology, Springer-Verlag: Berlin, 1996.
^ Daage, M.; Chianelli, R. R., "Structure-Function Relations in Molybdenum Sulfide Catalysts - the Rim-Edge Model", J. of Catalysis, 1994, 149, 414-427.
^ Chianelli, R. R.; Berhault, G.; Raybaud, P.; Kasztelan, S.; Hafner, J. and Toulhoat, H., "Periodic trends in hydrodesulfurization: in support of the Sabatier principle", Applied Catalysis, A, 2002, volume 227, pages 83-96
^ Kinetics and Interactions of the Simultaneous Catalytic Hydrodenitrogenation of Pyridine andHydrodesulfurization of Thiophene(John Wilkins, PhD Thesis, MIT, 1977)
^ Simultaneous Catalytic Hydrodenitrogenation of Pyridine and Hydrodesulfurization ofThiophene(Satterfield,C.N., Modell, M. and Wilkens, J.A., Ind. Eng. Chem. Process Des. Dev., 1980 Vol. 19, pages 154-160)
^ Deshpande, A., Bassi, A., Prakash, A. (2004) "Ultrasound-Assisted, Base-Catalyzed Oxidation of 4,6-Dimethyldibenzothiophene in a Biphasic Diesel-Acetonitrile System" Energy Fuels, 19 (1), 28 -34, 2005.

External links
Albemarle Catalyst Company (Petrochemical catalysts supplier)
UOP Company (Engineering design and construction of large-scale, industrial HDS plants)
Mustang Engineering Company (Description and flow diagram of an HDS unit, from an article published in the Oil & Gas Journal)
Hydrogenation for Low Trans and High Conjugated Fatty Acids by E.S. Jang, M.Y. Jung, D.B. Min, Comprehensive Reviews in Food Science and Food Safety, Vol.1, 2005
Oxo Alcohols (Engineered and constructed by Aker Kvaerner)
Catalysts and technology for Oxo-Alcohols
http://en.wikipedia.org/wiki/Hydrodesulfurization

Pervaporation

2009-02-16T21:12:00.000-08:00

Pervaporation is a method for the separation of mixtures of liquids by partial vaporization through a non-porous or porous membrane.

Contents
1 Theory
2 Applications
3 External links
4 References

Theory
The name of this membrane-based process is derived from the two basic steps of the process, firstly the permeation through the membrane by the permeate, then its evaporation into the vapor phase. This process is used by a number of industries for several different processes, including purification and analysis, due to its simplicity and in-line nature.
The membrane acts as a selective barrier between the two phases, the liquid phase feed and the vapor phase permeate. It allows the desired component(s) of the liquid feed to transfer through it by vaporization. Separation of components is based on a difference in transport rate of individual components through the membrane.
Typically, the upstream side of the membrane is at ambient pressure and the downstream side is under vacuum to allow the evaporation of the selective component after permeation through the membrane. Driving force for the separation is the difference in the partial pressures of the components on the two sides and not the volatility difference of the components in the feed.
The driving force for transport of different components is provided by a chemical potential difference between the liquid feed/retentate and vapor permeate at each side of the membrane. The retentate is the remainder of the feed leaving the membrane feed chamber, which is not permeated through the membrane. The chemical potential can be expressed in terms of fugacity, given by Raoult's law for a liquid and by Dalton's law for (an ideal) gas. It should be noted that during operation, due to removal of the vapor-phase permeate, the actual fugacity of the vapor is lower than anticipated on basis of the collected (condensed) permeate.
Separation of components (e.g. water and ethanol) is based on a difference in transport rate of individual components through the membrane. This transport mechanism can be described using the solution-diffusion model, based on the rate/ degree of dissolution of a component into the membrane and its velocity of transport (expressed in terms of diffusivity) through the membrane, which will be different for each component and membrane type leading to separation.

Applications
Pervaporation is effective for diluting solutions containing trace or minor amounts of the component to be removed. Based on this, hydrophilic membranes are used for dehydration of alcohols containing small amounts of water and hydrophobic membranes are used for removal/recovery of trace amounts of organics from aqueous solutions. Hydrophobic membranes are often PDMS based where the actual separation mechanism is based on the solution-diffusion model described above.
A relatively new membrane in the field of hydrophilic membranes is the ceramic membrane with the actual separation layer being made of amorphous silica. This is in fact a membrane which is porous, with pores ranging around 4 Å, large enough to let water molecules pass through and retain any other solvents that have a larger molecular size such as ethanol. Recent novell hydrophilic ceramic membranes can also be based on titania or zirconia.
Pervaporation is a very mild process and hence very effective for separation of those mixtures which can not survive the harsh conditions of distillation.
Solvent Dehydration: dehydrating the ethanol/water and isopropanol/water azeotropes
Continuous water removal from condensation reactions such as esterifications to enhance conversion and rate of the reaction.
Membrane introduction mass spectrometry
Removing organic solvents from industrial waste waters.
Combination of distillation and pervaporation/vapour permeation
Recently, a number of organophilic Pervaporation membranes have been introduced to the market. Organophilic Pervaporation membranes can be used for the separation of organic-organic mixtures, e.g.:
Reduction of the aromatics content in refinery streams
Breaking of azeotropes
Purification of extraction media
Purification of product stream after extraction
Purification of organic solvents

External links
http://www.membrane-guide.com/membrane_separation/pervaporation/pervaporation_europe.htm suppliers, products, news and facts for engineers involved in the design or the operation of pervaporation systems.
Technology of pervaporation Pervaporation with ceramic membranes
[1] Environmental Importance & as a Green Chemistry solution.

This chemistry article is a stub. You can help Wikipedia by expanding it.

References
Fontalvo Alzate, Javier (2006). Design and performance of two-phase flow pervaporation and hybrid distillation process.. Technische Universiteit Eindhoven, The Netherlands: JWL boekproducties. ISBN 978-90-386-3007-6.
Matuschewski, Heike (2008). MSE — modified membranes in organophilic pervaporation for aromatics/aliphatics separation.. www.desline.com: Desalination.
Retrieved from "http://en.wikipedia.org/wiki/Pervaporation"

http://en.wikipedia.org/wiki/Pervaporation

BASF to present BASIL™ ionic liquid process at technology transfer forum

2009-02-12T01:32:00.000-08:00

BASF to present BASIL™ ionic liquid process at technology transfer forum'Smart' process improves yields, economics of chemical operations
MOUNT OLIVE, N.J., May 10, 2004 -- Dr. Uwe Vagt, New Business Development, for BASF's Intermediates Division in Ludwigshafen, Germany, will present BASF's proprietary BASIL technology that utilizes ionic liquids to improve chemical operations on a commercial scale. The presentation will be at 9:30 a.m., on Monday, May 10, 2004, at the 21st Annual International Technology Transfer Forum, hosted by Technology Catalysts, at the Hyatt Regency Reston Town Center in Reston, Va.
BASF's BASIL (Biphasic Acid Scavenging utilizing Ionic Liquids) "smart" process technology economically solves several chemical processing problems associated with acid production during some chemical reactions.
Many organic chemical processes, such as esterifications, produce byproduct acids that must be scavenged in order to prevent decomposition of the primary reaction product, or to prevent unwanted side-reactions. To address this problem, tertiary amines, such as triethylamine, are typically added to the reaction mixture, resulting in the production of a solid ammonium salt. This solid presents a host of problems, including reduction of heat transfer and reaction rates, reduction of yields, and solids separation.
The BASIL process economically avoids the problems resulting from solids generation by making use of ionic liquids to scavenge acids. Instead of using a tertiary amine, a 1-alkylimidazole is used to scavenge acids produced. As the imidazole reacts with the acid, an alkylimidazolium salt is formed which is an ionic liquid at the reaction temperature. As a liquid, the alkylimidazolium salt can be easily removed by a liquid-liquid phase separation. In addition, economic reclamation of the 1-alkylimidazole through deprotonation is possible.
Ionic liquid technology provides the added advantage of having the alkylimidazole act as a nucleophilic catalyst, thereby improving reaction rates, and increasing yields and selectivities.
BASF representatives will be available throughout the technology transfer forum to answer questions and discuss potential licenses for this innovative technology.
Details about the Technology Catalysts 21st Annual International Technology Transfer Forum can be found at http://www.technology-catalysts.com//.
BASF - The Chemical Company. We don't make a lot of the products you buy. We make a lot of the products you buy better.®BASF Corporation, headquartered in New Jersey, is the North American affiliate of BASF AG, Ludwigshafen, Germany. We employ about 11,000 people in North America and had sales of approximately $9 billion in 2003. For more information about BASF's North American operations, or to sign up to receive news releases by e-mail, visit www.basf.com/usa.
BASF is the world's leading chemical company. Our goal is to grow profitably and further increase the value of our company. We help our customers to be more successful through intelligent system solutions and high-quality products. BASF's portfolio ranges from chemicals, plastics, performance products, agricultural products and fine chemicals to crude oil and natural gas. Through new technologies we can tap into additional market opportunities. We conduct our business in accordance with the principles of sustainable development. In 2003, BASF had sales of approximately $42 billion and over 87,000 employees worldwide. Further information on BASF is available on the Internet at http://www.basf.com/.
For more information, contact:Bill PaganoBASFTel: (973)426-2139E-mail: paganow@basf.com

離子液體

2008-05-15T19:14:00.000-07:00

離子液體當作溶劑的應用
近年來，離子液體在化學上的應用非常廣泛。由於離子液體具有極低蒸氣壓、低熔點、高極性、不可燃性、耐強酸、高熱穩定性、高導電度、電化學性佳及較廣的液體溫度範圍( -96 ~ 400 ℃)等特殊性質，可替代一般所用之揮發性有機溶劑(volatile organic compounds VOCs)，應用在化學合成，而且離子液體可在常壓下操作，不但可降低操作成本，且可消除VOCs對環境的污染，並可避免操作人員暴露於VOCs的風險，可再回收使用，所以離子液體有時被認為是一種新的綠色溶劑“green solvent”[1]。
離子液體是由陰離子及陽離子所組成的有機熔鹽，依不同組合方式，可超過一兆種。鹽類的熔點可高達 801 ℃或低到–96 ℃，所以為方便與高溫熔鹽做區分，通常把熔點低於 100 ℃的熔鹽稱為室溫離子液體(room temperature ion liquids-RTILs)，簡稱為離子液體(IL)，目前所發現的離子液體已超過 200 多種，常用的離子液體結構如圖一[2]。離子液體的陽離子包含有1-alkyl-3-methylimidazolium ([CnMIM]+, n為線性烷基碳的數目)、N-alkylpyridinium([CnPY]+)、tetraalkylammonium及tetraalkylphosphonium等陽離子，這些陽離子可結合不同的有機或無機的陰離子形成數目龐大的離子液體[3]，常見的陰離子有hexafluorophosphate(PF6-)、tetrafluoroborate(BF4-)、trifluoromethylsulfonate(CF3SO3-)、bis[(trifloromethyl)sulfonyl]amide [(CF3SO2)2N]-、trifluoroethanoate(CF3CO2-)、ethanoate(CH3CO2-)及halide(Br-,Cl-,I-)。
雖然早在 1914 年Walden即首先報導低溫的離子液體ethylammonium nitrate[4]，接下來於 1951 年Hurley首先合成室溫離子液體N-ethylpyridinium bromide- aluminium chloride[5]，但一直到 1970 年代，Osteryong和Willkers成功製備出chloroaluminate melts[6]，從此離子液體被大量應用於電化學、反應介質及催化劑。 1992 年，Wilkes等人發展出一係列咪唑(imidazolium)陽離子及BF4-、PF6-等陰離子組成的離子液體[7]，此類離子液體在空氣及水中相當穩定，使得這些類離子液體的應用引起廣大重視[8]，之後離子液體的發展大多以咪唑鹽類為主，進而發展出含DNA離子液體[9]、適合電化學的兩性離子液體[10]、磁性離子液體[11]及以胺基酸作為陰離子的離子液體等特殊功能的離子液體[12]，近年來離子液體的研究趨勢往功能性上發展。

離子液體的物理性質:
親水性：離子液體的親水性主要是取決於陰離子的結構，對水溶解度趨勢如圖一[3]，另外陽離子碳鏈愈長親水性愈差。
酸鹼性：一般離子液體可由陰離子部分判斷其酸鹼性，如表一[13]，因此可藉由陰離子的部分來調控溶劑的酸鹼度，而不必再加入額外的酸或鹼。
熔點：陽離子的對稱性愈低，會影響晶體的堆疊性，使熔點降低，而分子間的氫鍵會使熔點提高，常用雙烷基咪唑鹽類(dialkylimidazolium)的離子液體熔點，如表二。[14]
黏度：由於正負離子的作用力，使得離子液體黏度通常比水的黏度大很多，離子液體黏度的大小受分子間的氫鍵及凡得瓦作用力影響，陽離子碳鏈愈長，凡得瓦力愈強則黏度愈高。對於相同種類的陽離子，不同陰離子所形成的離子液體其黏度高低順序為Cl->PF6->BF4->NO3->(CF3SO3)2N-，如表二。
密度：大部分的離子液體是密度在 1 到 1.6 g/cm3之間，隨著溫度增加密度會降低。

離子液體在化學領域上有許多其特殊的物理性質，例如可溶解許多的無機和有機物質，但與部分的有機溶劑不互溶，可形成兩相反應系統，其優點是反應與分離可同時進行。不具揮發性，在高度真空下操作不易流失。不可燃性及有高的熱穩定性，加上其液體範圍廣，使其可應用的反應溫度範圍廣。另外，還可改變陰離子及陽離子的組成以調控其特性，所以離子液體亦被認為是“designer solvent”。離子液體的這些特殊物理性質，離子液體做為溶劑除了在電化學當作“nonaqueous elelctrolyte”外，其做為溶劑已被廣泛應用，其應用簡述如下：
a.有機合成的應用: 由於離子液體可溶解有機或無機物質，可當有機反應之溶劑取代傳統有機溶劑，不祇可減少傳統揮發性溶劑的危害，有時還可提高反應之選擇性和產率[16]，Jaeger等人首先以離子液體[EtNH3][NO3]進行Diels-Alder反應[17]，與有機溶劑甲苯及四氫夫喃比較[18]，可提高產率及Endo/Exo選擇性。Wasserscheid[19]等人及Ishida[20]等人合成不同對掌性陽離子型式的離子液體，此種對掌性離子液體於不對稱合成時可增加產物的立體選擇性，亦可作為對掌性分離中所填充靜相異構物。使用離子液體於合成時溶劑的應用，在過去十年呈現快速的發展。
b.催化反應的應用：離子液體可與催化劑形成共催化劑，增加催化劑的活性、選擇性及穩定性。例如Friedel–Crafts reaction在傳統條件下須加入固體的AlCl3作為催化劑，而[emim][AlCl3]可以代替催化劑及溶劑增加反應速率及選擇性[21]。離子液體在催化反應上的應用，包含hydrogenation [22]、hydroformylation[23]、olefin dimerisation[22]、Heck reaction[24]、alkoxycarbonylation[25]、catalytic oxidation[26]等反應；在酵素催化方面，離子液體可提高酵素功能[27]，以親水性的離子液體[C4MIM][BF4]不但可溶解有機反應物與生成物，而且可溶解酵素，且酵素的觸媒在其溶液仍具有活性且相當穩定，與在傳統的有機溶劑中酵素容易失去活性兩相比較，具有相當的優勢。
c.雷射脫附基質的應用：由於離子液體的不揮發性及可溶解生物樣品寡醣、蛋白質和高分子，可作為較軟性(soft)的離子源，將其吸收雷射之能量轉移至分析物中，除了可提升基質輔助雷射脫附的離子化效果[28,29]，亦可解決MALDI再現性的問題。
d.氣相層析管柱固定相的應用：在 1986 年Poole等人曾經使用alkylammonium和tetraalkylammonium鹽類作為氣相層析(GC)管柱的固定相[30,31]，但由於這種鹽類操作溫度的限制，降低其實用性。而Armstrong等人使用1-benzyl-3-methylimidazolium trifluoromethanesulfonate及1-(4-methoxyphenyl)-3-methylimidazolium Trifluoromethanesulfonate的離子液體的作為GC液相固定相(GLC)，分析揮發性或半揮發性有機物，分離效果相當好[32]，並利用[C4MIM][Cl]溶解25%(w/w) 的β-Cyclodextrins (β-CDs)[33]及合成具對掌性的離子液體[34]作為GC的對掌性固定相，分離對掌性化合物；由於這類的離子液體可耐高溫的特性，大大提高其商業化的潛力。
e.萃取的應用：疏水性的離子液體可被利用疏水性來萃取水中金屬離子[35,36]與染料萃取[37]，也利用其在柴油中氧化/萃取達成脫硫的目的[38]，Stepnowski使用固相萃取及Liu等人使用液相微萃取來濃縮水中的有機物[39,40]，Andre等人使用頂空式(head space)方法萃取分析物後再以GC分析[41]，離子液體具有特殊溶解性可萃取水溶液中球狀及棒狀金奈米[42]。
f.電化學的應用: 由於離子液體具導電性，可取代傳統的電解液，且有電化學視窗較廣的優點，可改善電化學過程中使用溶劑的偵測限制。使用離子液體在電化學的研究，開啟了離子液體在綠色化學領域之重視，另外也推展其在鋰離子電池[43]、燃料電池[44]、太陽能電池[45]、電容[46]及可偵測O2、CO2、SO2氣體的薄膜電極[47-51]等方面應用。
g.其它功能上的應用：離子液體可溶解纖維素[52]、作為溶膠-凝膠(Sol-Gel)的溶劑[53]及潤滑劑[54]等應用，所以離子液體的應用隨著新的離子液體發現而陸續增加，加上離子液體已突破實驗室的限制，已初步應用於商業發展上[55]，另外，離子液體可結合超臨界CO2於反應、萃取及分離相關應用[56]。

基本上，隨著離子液體的研究發展，其應用將更深入、更廣泛，使其在綠色化學的重要性相對增加，但其邁向廣泛工業上應用仍有許多問題需要克服[57-58]，此有待進一步研究來達成。
http://gc.chem.sinica.edu.tw/new-no-ionic.html

綠色化學的 12 基本法則

2008-05-15T19:00:00.000-07:00

1. 預防廢棄物的產生。
2. 充分利用反應物的所有原子。
3. 設計合成方法時，儘量考慮反應物與生成物的毒性。
4. 設計低毒性的化學品。
5. 少用或使用安全的溶劑與輔助物。
6. 為節省能源、降低環境衝擊，反應條件以常溫常壓狀態為主。
7. 使用永續資源為原料。
8. 簡化反應步驟，減少非必要性衍生物的產生。
9. 盡可能使用高選擇性的催化劑。
10. 設計可分解的化學品。
11. 污染物的及時偵測。
12. 慎選製程中的化學物質，以減少意外災害的發生。
http://www.nsc.gov.tw/_newfiles/popular_science.asp?add_year=2005&popsc_aid=140

Ionic liquid(From Wikipedia)

2008-05-15T18:47:00.000-07:00

An ionic liquid is a liquid that contains essentially only ions. Some ionic liquids, such as ethylammonium nitrate are in a dynamic equilibrium where at any time more than 99.99% of the liquid is made up of ionic rather than molecular species. In the broad sense, the term includes all molten salts, for instance, sodium chloride at temperatures higher than 800 °C. Today, however, the term "ionic liquid" is commonly used for salts whose melting point is relatively low (below 100 °C). In particular, the salts that are liquid at room temperature are called room-temperature ionic liquids, or RTILs. There also exist mixtures of substances which have low melting points, called Deep eutectic solvent, or DES, that have many similarities with ionic liquids.

History
The date of discovery, as well as discoverer, of the "first" ionic liquid is disputed. Ethanolammonium nitrate (m.p. 52-55 °C) was reported in 1888 by Gabriel.[1] However, one of the earlier known truly room temperature ionic liquids was [EtNH3]+ [NO3]- (m.p. 12 °C), the synthesis of which was published in 1914.[2] Much later, series of ionic liquids based on mixtures of 1,3-dialkylimidazolium or 1-alkylpyridinium halides and trihalogenoaluminates, initially developed for use as electrolytes, were to follow.[3][4] An important property of the imidazolium halogenoaluminate salts was that they were tuneable – viscosity, melting point and the acidity of the melt could be adjusted by changing the alkyl substituents and the ratio of imidazolium or pyridinium halide to halogenoaluminate.[5]
A major drawback was their moisture sensitivity and, though to a somewhat lesser extent, their acidity/basicity, the latter which can sometimes be used to an advantage. In 1992, Wilkes and Zawarotko reported the preparation of ionic liquids with alternative, 'neutral', weakly coordinating anions such as hexafluorophosphate ([PF6]-) and tetrafluoroborate ([BF4])-, allowing a much wider range of applications for ionic liquids.[6] It was not until recently that a class of new, air- and moisture stable, neutral ionic liquids, was available that the field attracted significant interest from the wider scientific community.
More recently, people have been moving away from [PF6]- and [BF4]- since they are highly toxic, and towards new anions such as bistriflimide [(CF3SO2)2N]- or even away from halogenated compounds completely. Moves towards less toxic cations have also been growing, with compounds like ammonium salts (such as choline) being just as flexible a scaffold as imidazole.

Characteristics
Ionic liquids are electrically conductive and have extremely low vapor pressure. (Their noticeable odours are likely due to impurities.) Their other properties are diverse. Many have low combustibility, excellent thermal stability, a wide liquid range, and favorable solvating properties for diverse compounds. Many classes of chemical reactions, such as Diels-Alder reactions and Friedel-Crafts reactions, can be performed using ionic liquids as solvents. Recent work has shown that ionic liquids can serve as solvents for biocatalysis [7]. The miscibility of ionic liquids with water or organic solvents varies with sidechain lengths on the cation and with choice of anion. They can be functionalized to act as acids, bases or ligands, and have been used as precursor salts in the preparation of stable carbenes. Because of their distinctive properties, ionic liquids are attracting increasing attention in many fields, including organic chemistry, electrochemistry, catalysis, physical chemistry, and engineering; see for instance magnetic ionic liquid.
Despite their extremely low vapor pressures, some ionic liquids can be distilled under vacuum conditions at temperatures near 300 °C.[8] Some ionic liquids (such as 1-butyl-3-methylimidazolium nitrate) generate flammable gases on thermal decomposition. Thermal stability and melting point depend on the components of the liquid. Thermal stability of various RTILs are available. The thermal stability of a task-specific ionic liquid, protonated betaine bis(trifluoromethanesulfonyl)imide is of about 534 K and N-Butyl-N-Methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide was thermally stable up to 640 K [9]
The solubility of different species in imidazolium ionic liquids depends mainly on polarity and hydrogen bonding ability. Simple aliphatic compounds are generally only sparingly soluble in ionic liquids, whereas olefins show somewhat greater solubility, and aldehydes can be completely miscible. This can be exploited in biphasic catalysis, such as hydrogenation and hydrocarbonylation processes, allowing for relatively easy separation of products and/or unreacted substrate(s). Gas solubility follows the same trend, with carbon dioxide gas showing exceptional solubility in many ionic liquids, carbon monoxide being less soluble in ionic liquids than in many popular organic solvents, and hydrogen being only slightly soluble (similar to the solubility in water) and probably varying relatively little between the more popular ionic liquids. (Different analytical techniques have yielded somewhat different absolute solubility values.)

Room temperature ionic liquids
Room temperature ionic liquids consist of bulky and asymmetric organic cations such as 1-alkyl-3-methylimidazolium, 1-alkylpyridinium, N-methyl-N-alkylpyrrolidinium and ammonium ions. A wide range of anions is employed, from simple halides, which generally inflect high melting points, to inorganic anions such as tetrafluoroborate and hexafluorophosphate and to large organic anions like bistriflimide, triflate or tosylate. There are also many interesting examples of uses of ionic liquids with simple non-halogenated organic anions such as formate, alkylsulfate, alkylphosphate or glycolate. As an example, the melting point of 1-butyl-3-methylimidazolium tetrafluoroborate or [bmim][BF4] with an imidazole skeleton is about -80 °C, and it is a colorless liquid with high viscosity at room temperature.
It has been pointed out that in many synthetic processes using transition metal catalyst, metal nanoparticles play an important role as the actual catalyst or as a catalyst reservoir. It also been shown that ionic liquids (ILs) are an appealing medium for the formation and stabilization of catalytically active transition metal nanoparticles. More importantly, ILs can be made that incorporate co-ordinating groups,[10], for example, with nitrile groups on either the cation or anion (CN-IL). In various C-C coupling reactions catalyzed by palladium catalyst, it has been found the palladium nanoparticles are better stabilized in CN-IL compared to non-functionalized ionic liquids; thus enhanced catalytic activity and recyclability are realized.

Low temperature ionic liquids
Low temperature ionic liquids (below 130 kelvins) have been proposed as the fluid base for an extremely large diameter spinning liquid mirror telescope to be based on the earth's moon.[12] Low temperature is advantageous in imaging long wave infrared light which is the form of light (extremely red-shifted) that arrives from the most distant parts of the visible universe. Such a liquid base would be covered by a thin metallic film that forms the reflective surface. A low volatility is important for use in the vacuum conditions present on the moon.

Food science
Ionic liquids have been used in food science. [bmim]Cl for instance is able to completely dissolve freeze dried banana pulp and the solution with an additional 15% DMSO lends itself to Carbon-13 NMR analysis. In this way the entire banana compositional makeup of starch, sucrose, glucose, and fructose can be monitored as a function of banana ripening.

Applications
Nowadays ionic liquids find a number of industrial applications which vary greatly in character. A few of their industrial applications are briefly described below; more detailed information can be found in a recent review article.
BASIL
The first major industrial application of ILs was the BASIL (Biphasic Acid Scavenging utilizing Ionic Liquids) process by BASF, in which a 1-alkylimidazole was used to scavenge the acid from an existing process. This then results in the formation of an IL which can easily be removed from the reaction mixture.[15] But the easier removal of an unwanted side-product (as an IL rather than as a solid salt) is not the only advantage of the IL based process. By using an IL it was possible to increase the space/time yield of the reaction by a factor of 80,000. It should, however, be kept in mind that improvements of such scale are rare.
Cellulose Processing
Occurring at a volume of some 700 billion tons, cellulose is the earth’s most widespread natural organic chemical and, thus, highly important as a bio-renewable resource. But even out of the 40 billion tons nature renews every year, only approx. 0.2 billion tons are used as feedstock for further processing. A more intensive exploitation of cellulose as a biorenewable feedstock has to date been prevented by the lack of a suitable solvent that can be used in chemical processes. Robin Rogers and co-workers at the University of Alabama have found that by means of ionic liquids, however, real solutions of cellulose can now be produced for the first time at technically useful concentrations [16]. This new technology therefore opens up great potential for cellulose processing.
For example, making cellulosic fibers from so-called dissolving pulp currently involves the use, and subsequent disposal, of great volumes of various chemical auxiliaries, esp. carbon disulfide (CS2). Major volumes of waste water are also produced for process reasons and need to be disposed of. These processes can be greatly simplified by the use of ionic liquids, which serve as solvents and are nearly entirely recycled. The “Institut für Textilchemie und Chemiefasern” (ITCF) in Denkendorf and BASF are jointly investigating the properties of fibers spun from an ionic liquid solution of cellulose in a pilot plant setup.
Eastman chemical’s DHF plant
Eastman operated an ionic liquid-based plant for the synthesis of 2,5-dihydrofuran from 1996 to 2004. However, the plant is now defunct because demand for the product has ceased.
Dimersol - Difasol
The dimersol process is a traditional way to dimerise short chain alkenes into branched alkenes of higher molecular weight. Nobel laureate Yves Chauvin and Hélène Olivier-Bourbigou at IFP (France) have developed an ionic liquid-based add-on to this process called the Difasol process. However, while may be licensed it has as yet not been put into commercial practice.
Petrochina
Petrochina have announced the implementation of an ionic liquid-based process called Ionikylation. This process, the alkylation of C4 olefins with iso-butane, is retrofitted into a 65,000 tonne per year alkylation plant, making it the biggest industrial application of ILs to date.
Degussa paint additives
Ionic liquids can enhance the finish, appearance and drying properties of paints. Degussa are marketing such ILs under the name of TEGO Dispers. These products are also added to the Pliolite paint range.
Air products - ILs as a transport medium for reactive gases
Air products make use of ILs as a medium to transport reactive gases in. Reactive gases such as trifluoroborane, phosphine or arsine, BF3, PH3 or AsH3, respectively, are stored in suitable ILs at sub-ambient pressure. This is a significant improvement over pressurised cylinders. The gases are easily withdrawn from the containers by applying a vacuum.
Linde's IL 'piston'
Whereas Air Product’s Gasguard system relies on the solubility of some gases in ILs, Linde are exploiting other gases’ insolubility in ILs. As mentioned above, the solubility of Hydrogen in ILs is very low. Linde now make use of this insolubility by using a body of ionic liquid to compress Hydrogen in filling stations; and in so doing they reduced the number of moving parts from about 500 in a conventional piston pump engine down to 8.
Nuclear industry
RTILs are extensively explored for various innovative applications in nuclear industry. It includes application of ionic liquid as extractant/diluent in solvent extraction systems, as alternate electrolyte media for the high temperature pyrochemical processing, etc. Fundamental studies on the extraction cum electrodeposition of fission products like uranium, palladium etc., from spent nuclear fuel using RTILs as extractants are reported. Reports on employing using Ionic liquids as non-aquoues electrolyte media for the recovery of uranium [18]and useful fission products like palladium [19] and rhodium [20] from spent nuclear fuel are also available.Studies on the electrochemical behavior of uranium(VI) in ionic liquid, 1-butyl-3-methylimidazolium chloride and also the recovery of valuable fission products from tissue paper waste was studied in room temperature ionic liquids.

Safety
Due to their non-volatility, effectively eliminating a major pathway for environmental release and contamination, ionic liquids have been considered as having a low impact on the environment and human health, and thus recognized as solvents for green chemistry. However, this is distinct from toxicity, and it remains to be seen how 'environmentally-friendly' ILs will be regarded once widely used by industry. Research into IL aquatic toxicity has shown them to be as toxic or more so than many current solvents already in use [22]. A review paper on this aspect has been published in 2007.[23] Available research also shows that mortality isn't necessarily the most important metric for measuring their impacts in aquatic environments, as sub-lethal concentrations have been shown to change organisms' life histories in meaningful ways. According to these researchers balancing between zero VOC emissions, and avoiding spills into waterways (via waste ponds/streams, etc.) should become a top priority. However, with the enormous diversity of substituents available to make useful ILs, it should be possible to design them with useful physical properties and less toxic chemical properties.
With regard to the safe disposal of ionic liquids, a 2007 paper has reported the use of ultrasound to degrade solutions of imidazolium-based ionic liquids with hydrogen peroxide and acetic acid to relatively innocuous compounds.[24]
Despite their low vapor pressure many ionic liquids have also found to be combustible and therefore require careful handling [25]. Brief exposure (5 to 7 seconds) to a flame torch will ignite these IL's and some of them are even completely consumed by combustion.

http://en.wikipedia.org/wiki/Ionic_liquid

思博網無授權之論文

2008-04-11T03:17:00.000-07:00

中药决明子的研究进展
http://www.ceps.com.tw/ec/ecjnlarticleView.aspx?jnlcattype=0&jnlptype=0&jnltype=0&jnliid=2587&issueiid=33246&atliid=541033

微波萃取技术在天然产物提取中的应用

2008-04-11T02:45:00.000-07:00

http://www.chinamtcm.com/html/30773.htm
微波萃取的原理
　　微波是一种频率在300MHZ至300GHZ之间的电磁波，它具有波动性、高频性、热特性和非热特性四大基本特性。常用的微波频率为2450MHZ。微波加热是利用被加热物质的极性分子（如H2O、CH2Cl2等）在微波电磁场中快速转向及定向排列，从而产生撕裂和相互摩擦而发热。传统加热法的热传递公式为：热源→器皿→样品，因而能量传递效率受到了制约。微波加热则是能量直接作用于被加热物质，其模式为：热源→样品→器皿。空气及容器对微波基本上不吸收和反射，这从根本上保证了能量的快速传导和充分利用。
　　Pare等提出假设：微波透过对微波透明的溶剂，到达植物物料内部维管束和腺细胞内，细胞内温度突然升高，连续的高温使其内部压力超过细胞空间膨胀的能力，从而导致细胞破裂；细胞内的物质自由流出，传递到周围被溶解。微波可选择性加热不同极性分子和不同分子的极性部分，从而使其从中分离，进入到介电常数较小、微波吸收能力相对较差的溶剂中，从而有效成分被提取。
　　自Pare提出微波破壁的假设以来，已有一些学者提出了反对意见。有学者通过对新鲜银杏叶微波辅助提取后微观结构的变化观察发现，植物细胞结构发生较为明显的变化，主要表现在有质壁分离现象，细胞器、淀粉粒等胞内物质被破坏，但微波辅助提取没有使细胞壁破裂。
　　无论微波破壁与否，微波对极性物质的提取的优越性，已得到了众多研究者的肯定。
微波萃取的特点　　微波萃取技术作为一种新型的萃取技术，有其独特的特点。首先体现在微波的选择性，因其对极性分子的选择性加热从而对其选择性的溶出。其次MAE大大降低了萃取时间，提高了萃取速度，传统方法需要几小时至十几小时，超声提取法也需半小时到一小时，微波提取只需几秒到几分钟，提取速率提高了几十至几百倍，甚至几千倍。最后，微波萃取由于受溶剂亲和力的限制较小，可供选择的溶剂较多，同时减少了溶剂的用量。另外，微波提取如果用于大生产，则安全可靠，无污染，属于绿色工程，生产线组成简单，并可节省投资。
2、蒽醌类
　　郝守祝等研究了微波技术对大黄游离蒽醌浸出量的影响，采用正交实验考察了微波输出功率、物料粒径、浸出时间三个因素对提取率的影响，优选最佳浸出方案。以优选出的微波浸提方案和常规煎煮法及乙醇回流法比较，结果物料粒径对蒽醌成分浸出影响极显著，功率对浸出影响显著，时间对浸出有一定影响。微波提取法对大黄游离蒽醌的提取率明显优于常规煎煮法，同乙醇回流法相当。
　　沈岚等以大黄、决明子中不同极性的蒽醌类成分为指标成分，采用正交试验设计分别考察提取率，结果显示微波萃取法对大黄、决明子中不同极性成分提取选择性并不明显，而同一温度条件下，根茎类中药大黄中大黄素、大黄酚、大黄素甲醚的提取率明显高于种子类中药决明子中相同成分的提取率。

降脂灵片中决明子定性和定量分析方法的研究

2008-04-07T20:55:00.000-07:00

The study on qualitative analysis and quantitative analysis method of Semen Cassiae in JiangZhiLing tablet
http://scholar.ilib.cn/A-tianjykdxxb200101014.html
<<天津医科大学学报 >>2001年01期 ZHANG Qi

[摘要]目的：通过对决明子的定性和定量分析来控制降脂灵片的质量。方法：采用薄层层析法对决明子进行定性分析；应用高效液相色谱法，采用ODS-C18色谱柱，以甲醇：0.1％高氯酸(80:20)为流动相，检测波长为365nm，测定决明子中大黄素的含量。结果：在0.05～0.8mg/L浓度范围内，线性关系良好，回归方程为Y=32.92+5391.86X，r=0.9998，平均回收率为98.70%。结论：本法简便可靠准确，可以作为质控方法。Objective :The quality of JiangZhiLing tablet was controlled based on the qualitative analysis and quantitative analysis of Semen Cassiae. Methods: Qualitative analysis of Semen Cassiae was performed by TLC (thin-layer-chromatograph); HPLC(high-performance liquid chromatograph) was applied to determine the quantity of Emodin in Semen Cassiae at 365nm wavelength, in which ODS-C18 volume, 0.1%methanol flow phase and PCA (perchloric acid)were used. Results: Emodin' s detection linear range is 0.05～0.8mg/L. The regression equation is Y=33.92+5391.86X, r=0.9998, average recovery is 98.70%. Conclusion: This method is simple and reliable enough to be used as the method of quality-control. 关键词：降脂灵片 , 决明子 , 大黄素 , 薄层层析法 , 高效液相色谱法

决明子微波萃取法与常用提取方法的比较

2008-04-07T20:52:00.000-07:00

Comparative study on the extraction of anthraquinone from Semen Cassiae by MAE and commonly used extraction methods
http://scholar.ilib.cn/Abstract.aspx?A=zhongcy200403007
<<中成药 >>2004年03期冯年平 , 沈岚 , 韩朝阳 , 朱沪平 , 范广平
目的:通过对决明子微波萃取法(MAE)与常用提取方法(索氏提取法、超声提取法、水煎法)的比较研究,评价MAE提取中药有效成分的特点,初步探索MAE的机理.方法:采用分光光度法测定决明子提取液中总蒽醌的含量;采用显微照相仪对表面结构及横切面状况进行观察.结果:MAE的提取率最高,是超声提取法的16倍,是索氏提取法的3倍,是水煎法的1.1倍,且MAE仅5min就已超过超声1h的提取率,15min已达到或接近索氏提取2h和水煎法的提取效果;显微观察表明,微波直接造成表面结构的破坏.结论:MAE用于中药决明子的提取具有高效、节能、省时的特点,可以在中药制药中进一步推广应用.
关键词：微波萃取 , 决明子 , 总蒽醌 , 分光光度法

决明子的研究与临床应用

2008-04-07T20:49:00.000-07:00

http://0rz.tw/973RM
作者 : 华海清, 中国中药杂志
摘要撰写人 : TsingHua
浏览次数: 15
出版日期：九月 25, 1995
决明子的研究与临床应用华海清（南京中医学院文献所２１００２９）决明子为豆科植物决明ＣａｓｓｉａｏｂｔｕｓｉｆｏｌｉａＬ。或小决明Ｃ．ｔｏｒａＬ．的成熟种子，入药始载于《神农本草经》。功能祛风散热，清肝明目，润肠通便，临床常用于目赤肿痛、青盲、雀目、大便秘结等病症。现代研究认为，本品除含蒽酯类物质外，尚含氨基酸、微量元素、维生素Ａ等多种营养成分，能显著地降低血浆胆固醇和甘油三脂的含量，降血压，并能抑制血小板凝聚，故对，乙脑疾病有良好的防治作用，是一味有相当开发前景的保建药品。现对其药化药理及临床研究状况作一概述。１决明子的化学成分决明与小决明种子均含蒽醌类物质如大黄酚（ｃｈｒｙｗｅｈａｎｏｌ），大黄素（ｅｍｏｉｎ），大黄素甲醚（ｐｈｙｓｃｉｏｎ），芦荟大黄素（ａｌｃｏ－ｅｍｅｄｉｎ），大黄酸（ｒｈｅｉｎ），美决明子素（ｏｂｕｔｓｉｆｏｌｉｎ），决明素（ｏｂｔｕｓｉｎ）等多种物质，决明种子含葡萄糖美决明子素（ｇｌｕｃｏ－ｏｂｔｕｓｉｆｏｌｉｎ），葡萄糖橙黄决明素（ｇｌｕａｒａｕｒａｎｔｉｃａｏｂｔｕｓｉｎ），决明子内酯（ｔｏｒａｌａｃ－ｔｏｎｅ）及２个新内酯：异决明子内酯（ｉｓｔｏｌａｃｔｏｎｅ）和ｃａｓｓｉａｌａｃｔｏｎｅ，最近又发现了３个新的蒽醌，２个新的蒽醌葡萄糖甙和２个新的茶并吡喃酮类。决明种子中含油４．６５％～５．７９％，油的主要成分为棕榈酸、硬脂酸油酸、亚油酸，尚含组氨酸、蛋氨酸等２０多种氨基酸及铁、锌、锰、铜、镍、钴、铝等多种微量元素和维生素Ａ类物质如β－胡萝卜素等。小决明的种子中含去氧大黄酚（ｃｈｒｙｓａｒｏｂｉｎ），最近又新发现了３个新的蒽醌糖甙，２个新的蔡并吡喃酮糖甙。油中含少量的锦葵酸（ｍａｌｖａｌｉｃａｃｉｄ）、萍婆酸（ｓｔｅｒｃｕｌｉｃａｃｉｄ）以及１５种舀醇，还含有（△￣５５－ｓｔｅｒｏｌｓ），（△￣７－ｓｔｅｒｏｌｓ）和少量饱和的笛醇类；种子含总灰分１０．３８％，主要是Ｃａ，Ｎａ，Ｋ，Ｐ，其它还含有葡萄糖、半乳糖、木糖、棉子糖、红镰要素（ｒｎｂｒｕ－ｆｕｓａｒｉｎ）和去甲红镰要素（ｎｏｒｒｕｂｒｕｆｕａｍｎ），此外，还含蛋白质及人体必需的微量元素￣［１，２］。２决明子的药理作用２．１降压作用决明子水浸液及醇浸液对麻醉动物有降压及刮尿作用￣［３］，使自发性遗传性高血压大鼠收缩压和舒张压均明显降低，其作用和持续时间显著长于利血平￣［４］。２．２降血脂作用用实验性高胆固醇家兔，加决明子粉１０ｇ／只，连续３个月，结果表明可抑制血清胆固醇升高和主动脉粥样硬化斑点形成￣［３］。用高胆固醇血症小鼠模型在饲料中给予７％决明子粉，连续２月，结果模型组与决明子组血情总胆固醇（ＴＣ）均明显升高；模型组高密度脂蛋白。胆固醇（ＨＤＬ－Ｃ）含量有升高趋势，而决明子组ＨＤＬ－Ｃ则明显升高；模型组ＨＤＬ－Ｃ／ＴＣ比值明显降低，而决明子组则接近于正常水平￣［５］。实验表明蒽醌糖甙是其降脂的主要成分之一。因其有导泻作用，能减少肠道对胆固醇的吸收及增加排泄，通过反馈调节低密度脂蛋白代谢，从而降低血清胆固醇水平，延缓和抑制动脉粥样硬化斑块形成￣［６］。２．３对小鼠免疫功能的影响３组小鼠，分别注射决明子水煎醇沉剂１５ｇ／ｋｇ，环磷酰胺１０ｍｇ／ｋｇ，生理盐水０．２ｍｌ作为对照，每日１次，连续７天，观察对免疫功能的影响。结果表明，决明子水煎醇沉剂可使小鼠胸腺萎缩，结构改变显著，但对脾脏结构无明显影响，说明决明子对细胞免疫功能有抑制作用；对体液免疫功能无明显影响；而对巨噬细胞吞噬功能有增强作用￣［７］。２．４抑菌作用决明子醇浸出物或煎剂对多种皮肤真菌及细菌有抑制作用￣［８］。所含的芦荟大黄素，其抑菌的有效浓度为１５～２５μｇ／ｍｌ，对培养基中的金黄色葡萄球菌呼吸、核酸及蛋白质的合成具有明显的抑制作用；所含去氧大黄酚对红色发癣菌和须发癣菌的抑菌浓度为３μｇ／ｍｌ，大小孢子菌为５μｇ／ｍｌ，石青样小孢菌和地丝念株菌为１０μｇ／ｍｌ；所含大黄素对金黄色葡萄球菌、大肠杆菌、绿脓杆菌、弗氏痢疾杆菌、甲型链球菌、肺炎球茵、流感杆菌、卡他球菌以及白喉、枯草、副伤寒杆菌等在体外均有不同程度的抑制作用￣［９］。２．５抗癌作用体外试验对人体子宫颈癌细胞培养株系ＪＴＣ－２６抑制率在９０％以上。所含大黄酸对小鼠黑色素瘤有较强的抑制作用，５０ｍｇ／ｋｇ抑制率为７６％，对癌细胞醇解有明显的抑制作用￣［１０］。２．６明目作用给家兔或狗按２ｍｌ／ｋｇ体重计算，每天上、下午各灌胃给５０％决明子煎剂一次，测定眼睫状肌中ＬＤＨ活性。结果表明，ＬＤＨ的活性较蒸馏水灌胃对照组显著提高（Ｐ＜０．０１），提示决明子有激活眼组织中ＬＤＨ的功能而起到明目作用。此外，决明子中含微量元素锌、维生素Ａ亦与明目作用有关￣［１１］。２．７其它作用决明子流浸膏给小鼠１ｇ后３～５ｈ泻下作用达到高峰，其泻下成分可能为番泻甙Ａ和大黄酚二惠酮甙￣［１２］；决明子所含的橙黄决明素和决明素对ｃＡＭＰ磷酸二酯酶具有抑制作用；所含茶并吡喃糖甙对半乳糖胺所致的肝损害有明显的保护作用￣［１］。２．８毒性给大鼠饲料中加入决明子１６％～３２％，至８天时随着决明子剂量的增加，大鼠的体重亦增加，饲料及水的饮用量减少。当饲料中加入决明子的量≥８％时，可见大鼠睾丸中精子减少，骨髓减轻，骨髓中多色红细胞数量减少，中性白细胞与淋巴细胞比值增加等￣［１］。３决明子的临床应用决明子味甘、苦、咸，性微寒，善入肝、大肠经。甘能补益，苦寒能清热，故临床多用于风热犯目或肝肾不足所致多种眼科疾患，为眼和病：变之要药；又因其味咸，有润下之功，故还常用于热结津亏之便秘。近年来发现本品有较好的降血压及降血脂作用而用治高血压、高血脂等病证。３．１用于眼科疾患决明子有良好的疏风散热、清肝明目之功，用于急性结膜炎、急性角膜炎等眼部感染有显著疗效。如治急性结膜炎，临床可用决明子配菊花９ｇ、蔓荆子６ｇ、木贼草６ｇ，水煎服；治急性角膜炎，用决明子１５ｇ，配菊花９ｇ、谷精草９ｇ、荆芥９ｇ、黄连９ｇ、木通１２ｇ，水煎服。《摘元方》载治目赤肿痛及风热头痛，用决明子炒研，茶调，敷两侧太阳穴可取效。除用于实证病变外，本品还常用于肝肾两亏，童子失养所致视物模糊、视力减退及青盲、雀目等证。如《外台秘要》用决明子杵散服，治积年失明不识人；《冯氏锦囊》自创还明散，药用决明子（炒）６ｇ、白蒺藜（炒，去刺）１２ｇ、防风６ｇ，为细末，入猪肝内蒸熟食之（去药），治视物模糊不清。笔者在临床上遇肝肾不足，目失濡养之病变，多于六味地黄丸中加入决明子一味，常获效验。３．２用于便秘决明子有较好的润肠通便作用，无论血虚肠燥或热结便秘均可使用，尤多用于习惯性便秘，可取本品１８ｇ，郁李仁９ｇ，沸水冲泡代茶饮。已故名老中医叶橘泉先生常用本品治慢性便秘及脑卒中后顽固性便秘可取显效。方法是取决明子５００ｇ，炒香研细末，水泛为丸，每次３ｇ，每日３次，连服３～５天，大便即可自然通畅，且排出成形粪便而不泄泻，此后如继续每日眼少量，可维持经常便通，并能促进食欲，恢复健康￣［１３］。３．３用于高血压病决明子有一定的降压作用，其作用持久而缓慢，每需长服久服方能巩固疗效，因其有清中寓养之特点，故尤适用于阴虚阳亢之高血压患者，可取决明子炒黄捣成粉，加糖泡开水服，每次３ｇ，每日３次。亦可用决明子１５ｇ配夏枯草９ｇ，水煎，连服１月有显效。周然等报道用决明子茶治疗高血压１７例，显效６例，有效６例，无效５例￣［１４］。笔者在临床上无论治何种证型之高血压，每于辨证方中加入此味，可显著提高临床疗效。３．４用于高胆固醇血症实验表明，决明子有较好的降低血清胆固醇之作用，验之临床，每获效验。据报道，取决明子５０ｇ，水煎分２次服，或制成糖浆剂、片剂治疗高胆固醇血症１００例，治疗前后血清胆固醇平均下降了９３．１％。用药２周内有８２％降至正常水平；４周内降至正常水平者占９６％，总有效率达９２％。其缺点是需长期服用，否则易复升；同时还需达到一定的剂量（每日５０ｇ）方能取效，量少则无效￣［１５］。３．５用于小儿疳积本病系小儿科疑难病证，治疗较为棘手，而用决明子往往能获得较好的疗效。如《江西草药》记载用决明子９ｇ，研末，鸡肝１具，捣烂，白酒少许，调和成饼，蒸熟服可治本病。近有报道，用决明子２０ｇ，鸡内金、山楂各１０ｇ，鲜鸡肝１具，将鸡肝捣如泥状与３味药粉和匀，包扎后放２次淘米水中煎煮，先食药后饮汁，治１４５例，愈１２７例，一般１剂见效￣［１６］．笔者亦曾在临床用本法试治数例，确有效果。３．６用于热毒疮痈、口疮等证取决明子苦寒泄热，消肿毒之功。《普济方》记载，用决明子（生用）一升，捣碎，生甘草３０ｇ，切碎，水三升，煮取一升，分二次温服，可治发背。刘氏报道用本品可治初期乳痈，取决明子２５～１００ｇ，根据乳痈患者病情的轻重和体质强弱增减药量，水煎服，一般１～３剂即愈￣［１７］。用治口疮疾病，可用本品单味煎水含漱，或在辨证施治基础上加用此品，都能收到明显的疗效，尤其对治疗多年未愈，或长期服用维生素Ｂ＿２无效之口疮亦有良效。实证者可用炒决明子３０ｇ，生地１５ｇ，丹皮９ｇ，生石膏３０ｇ，升麻９ｇ，木通６ｇ，甘草梢６ｇ，当归１０ｇ，玄参１５ｇ，水煎服；虚证（阴虚火旺）口疮者，则可用炒决明子３０ｇ，知母１２ｇ，生地１２ｇ，泽泻１２ｇ，炒黄柏９ｇ，丹皮１０ｇ，获等１５ｇ，水煎服。此外，经适当配伍，决明子还可用治急慢性呼吸道疾病、胆囊炎、胆石症、胰腺炎、肝炎、肝硬化腹水、肾炎、泌尿系感染￣［１８］、霉菌性阴道炎￣［１９］等，均有较好的疗效。４决明子的开发利用价值及前景决明子不仅具有广泛的药用价值而且还是一味良好的保健药品。早在２０００多年前的本草经典著作《神农本草经》中就有“久服能益精光，轻身”等记载。但令

微波萃取技术在中药及天然产物提取中的应用

2008-04-07T20:44:00.000-07:00

http://www.yaofen.com/Newfxjs/analysis_app.asp?id=1904
微波萃取，即微波辅助萃取(MAE)，是根据不同物质吸收微波能力的差异使得基体物质的某些区域或萃取体系中的某些组分被选择性加热，从而使得被萃取物质从基体或体系中分离，进入到介电常数较小、微波吸收能力相对差的萃取剂中，达到提取的目的。
1、微波萃取的机理微波是一种频率在300MHZ至300GHZ之间的电磁波，它具有波动性、高频性、热特性和非热特性四大基本特性。常用的微波频率为2450MHZ。微波加热是利用被加热物质的极性分子(如H2O、CH2Cl2等)在微波电磁场中快速转向及定向排列，从而产生撕裂和相互摩擦而发热。传统加热法的热传递公式为：热源→器皿→样品，因而能量传递效率受到了制约。微波加热则是能量直接作用于被加热物质，其模式为：热源→样品→器皿。空气及容器对微波基本上不吸收和反射，这从根本上保证了能量的快速传导和充分利用。
2、微波萃取的特点
①体现在微波的选择性，因其对极性分子的选择性加热从而对其选择性的溶出。
②MAE大大降低了萃取时间，提高了萃取速度，传统方法需要几小时至十几小时，超声提取法也需半小时到一小时，微波提取只需几秒到几分钟，提取速率提高了几十至几百倍，甚至几千倍。
③微波萃取由于受溶剂亲和力的限制较小，可供选择的溶剂较多，同时减少了溶剂的用量。另外，微波提取如果用于大生产，则安全可靠，无污染，属于绿色工程，生产线组成简单，并可节省投资。微波萃取一般适用于热稳定性的物质，对热敏性物质，微波加热易导致它们变性或失活；要求物料有良好的吸水性，否则细胞难以吸收足够的微波能将自身击破，产物也就难以释放出来；微波提取对组分的选择性差。
3、微波萃取的应用微波萃取广泛用于苷类、黄酮类、帖类、多糖、生物碱等成分的提取。
①生物碱类 Ganzler等从羽扇豆种子中提取金雀花碱(斯巴丁)，与传统的振摇提取法比较，微波法提取物中斯巴丁含量比振摇法高20%，而且速度快，溶剂消耗量也大大减少。 Brachet A等从可可叶中提取可卡因和苯甲酰芽子碱，考察了提取溶剂、粒径、样品湿度、微波功率及照射时间等参数。所得提取物与传统方法相当，但只用时30秒。有学者研究微波技术对麻黄中麻黄碱浸出量的影响，比较了微波提取与常规煎煮方法的优劣，结果微波法对麻黄碱的浸出量明显优于煎煮法，并且半量麻黄粗粉浸出量明显优于全量麻黄饮片，与中医药理论“煮散减半”相符。另有学者用微波法提取黄连中的小檗碱，以干固物和小檗碱含量测定结果为指标，比较微波和回流两种方法。干固物测定结果显示，在单位时间内微波处理较回流提取具有明显优势；以小檗碱含量为指标，结果显示回流提取小檗碱含量高于微波提取。
②蒽醌类郝守祝等研究了微波技术对大黄游离蒽醌浸出量的影响，采用正交实验考察了微波输出功率、物料粒径、浸出时间三个因素对提取率的影响，优选最佳浸出方案。以优选出的微波浸提方案和常规煎煮法及乙醇回流法比较，结果物料粒径对蒽醌成分浸出影响极显著，功率对浸出影响显著，时间对浸出有一定影响。微波提取法对大黄游离蒽醌的提取率明显优于常规煎煮法，同乙醇回流法相当。沈岚等以大黄、决明子中不同极性的蒽醌类成分为指标成分，采用正交试验设计分别考察提取率，结果显示微波萃取法对大黄、决明子中不同极性成分提取选择性并不明显，而同一温度条件下，根茎类中药大黄中大黄素、大黄酚、大黄素甲醚的提取率明显高于种子类中药决明子中相同成分的提取率。
③黄酮类刘传斌等把微波破细胞与溶剂提取相结合的方法提取高山红景天愈伤组织中红景天苷。将药材经1分钟微波处理后，室温下水提取10分钟，可将红景天苷充分提取出来，与传统提取方法相比，前者具有时间短、不需加热、提取液中杂质少等优点。段蕊等也用此方法提取银杏叶中的黄酮成分。用微波处理5分钟后，以70%乙醇回流提取1小时，得到提取物中黄酮类物质的量比未用微波处理的高出18.8%，纸层析表明在使用的微波温度下，黄酮类物质性质不发生改变。李嵘等也用该法研究了银杏黄酮苷的提取工艺，同样得到较理想的结果。此外，阎欲晓等从生姜中提取抗氧化物质，结果发现先用微波处理5分钟，黄酮的提取率明显提高。郭振库等对黄芩中黄芩苷微波提取作了研究，用正交设计优选了最佳工艺为70%微波功率(最大功率850瓦)下，以35%乙醇作溶剂，溶剂30倍量，压力0.15Mpa，恒压时间30秒即可获得较好的得率，比超声法高出近10%。张梦军等用均匀设计法考察了微波提取甘草黄酮的最佳条件为：固液比1/8，乙醇浓度78%，微波功率388瓦，提取时间1分钟。微波法提取率(24.6mg/ml)明显优于水提法(11.4mg/ml)。陈斌等研究微波萃取葛根异总黄酮的工艺，用77%乙醇，固液比1/14，在低于60℃条件下，微波间歇处理3次，总黄酮浸出率达95%以上，与传统的热浸提相比，不仅产率高，而且速度快，节能。王绢等应用微波萃取葛根中的总黄酮、葛根素，结果表明提取效率明显提高，提取时间明显缩短，有效成分的得率显著提高。
④皂苷类有研究发现，用微波法提取重楼皂苷，结果微波处理5分钟的效果即基本达到2小时常规加热的效果，而且杂质少，微波提取10分钟即可认为皂苷已提取完毕。
⑤有机酸郭振库等应用自行设计的具较高压力控制精度的专用微波制样系统，对金银花中有效成分绿原酸和异绿原酸类化合物的提取条件进行了考察，并与超声波提取比较，提取率比超声波高近2成。郭锦堂等应用微波提取甘草酸，8分钟可得到与连续回流提取3小时相当的结果。
⑥多糖类新疆石河子大学药学院的工作者在用微波萃取多糖的研究上作了大量工作，提取的植物包括甘草、商陆、肉苁蓉、红景天根、红景天叶、黄芪、党参等。他们在MCL-3微波反应器中，用一定量石油醚、乙醚和80%乙醇回流提取20分钟，残渣再放入微波炉中，用水提取20分钟后测定多糖含量，结果提取率均高于传统方法，提取时间缩短了约12倍。唐克华等用微波提取天仙果多糖，初步确认微波提取天仙果多糖宜在80℃的碱性介质中结合微波前处理可获得较高提取率。刘依等用微波处理板蓝根，然后用水煎煮提取板蓝根多糖，含量测定结果表明粗多糖得率达到33.062%，质量分数达75.211%，优于单独使用水煎法。也有人用微波提取茶叶多糖，结合醇沉法制备茶多糖得率为2.52%，紫外和红外光谱分析证实，该工艺对茶多糖制品化学结构无影响。另外还有人用微波法提取大豆中低聚糖，得率比非微波条件有明显提高，溶出时间大为缩短，只需6分钟。
⑦挥发油当前，已有很多国外学者开始利用微波法萃取挥发油。加拿大环境署Pare于1991年申请了美国专利，对天然产物包括薄荷、欧芹、雪松叶和大蒜等，采用对微波透明(己烷等)或部分透明(甲醇、二氯甲烷等)的溶剂。专利中所阐述的萃取过程及要求为：①材料是粉碎的，被提取成分应能吸收微波射线；②材料放入对微波透明或部分透明的提取剂中；③用一定频率的微波辐射提取；④分离提取物；⑤回收提取物，或者直接使用(如果不需要分离)。提取物分析结果表明，微波法在以下方面优于传统水蒸气蒸馏法：提取率、提取物质量、提取时间、所需费用以及操作步骤。另有国外文献报道，用微波技术萃取香薄荷、茴香、牛膝草叶、百里香叶及鼠尾草属植物中的精油。国内学者也较多用微波萃取挥发油，新疆石河子大学药学院鲁建江等人从藿香、魁蒿叶、新疆党参、新疆孜然果实、红花、红景天根茎叶中用微波提得挥发油，结果均比水蒸气蒸馏提取率高且用时短。另外尚有香叶天竺葵和山苍子挥发油微波萃取的报道。
⑧其他目前，微波萃取技术除应用于以上主要成分之外，对另外一些成分，如甾体、萜类化合物、植物油、香料、色素等的提取也有报道。如：用此法从棉籽中提取棉酚、从豆类中提取蚕豆嘧啶葡萄糖苷、金雀花碱等天然化合物,提取效率大大高于索氏提取法和超声法,而且消耗溶剂少、时间短。韩伟等用微波辅助萃取法,研究提取青蒿素与传统提取法相比,提取率有明显地提高。
参考：1、傅荣杰，冯怡（《微波萃取技术在天然产物提取中的应用》）
2、杨红，韩晓静（《天然药物的提取分离新技术研究进展》）

決明子萃取物.Cassia Seed

2008-04-07T20:42:00.000-07:00

http://www.good-sa.com.tw/375.html
一、 Introduction :

Cassia Seed
Nickname:
The grass is definitely clear, the horse's hoofs definitely clear and false green lentil
Scientific term: SemenCassiae
Source: For the bean section plant definitely clear CassiaobtusifoliaL.Of seed
Produce in : There is cultivation in greatly parts of regions of the whole China
The lord produces in: Anhui, Jiangsu, Zhejiang, Sichuan
Plant appearance: Gets the half bush form herbage for a year, high 1~2 ms

The feather form compound leaf gets with each other;Little leaf's 3 rightnesses, pour an oval or long circle form to pour oval, grow a 1.5~6.5 cms, the breadth 0.8~3 cms, carry bluntness first, Ji department circular, bias, young hour both sides Shu long fluff;The Tuo leaf's taper, fall early.

The flower becomes to get the Yi;E slice 5, separate;Flower petal 5, yellow, have claw;Can teach stamen 7, below 3s are more flourishing;The ovary contain handle, white.Jia fruit line form.

The seed most, rhombus, the hazel, there is sheen, the flower expects for, the fruit expects .

Adopt to make: The autumn has already harvested familiar fruit, drying in the sun, beating seed.

Sex form:The seed Leng square or short cylinder form, the both ends parallel inclination, grow a,

The surface green brown or dark brown, smooth have sheen.

Flatter carry another inclined point while carrying, carry on the back stomach to face each Leng line which have a Tu to rise, Leng line two sides are each to have inclined one to symmetry and the color more shallow line form cave line.

The quality is strong and tough, not easily broken up.Grow skin thin, cotyledon 2, yellow.The flavor tiny bitterness.
The function lord cures:
Pure and hot and clear eyes, the smooth bowel relaxs bowel.
Be used for the eyes red Se pain, abashed the much clearer tears, headache faint, eyes dark not clear and big constipation knot.

二、The ingredient of Cassia Seed :
Chemistry composition:
Contain a greatly yellow vegetable(emodin), greatly yellow Fen(chrysophanol), greatly yellow plain AN ether(physcion), definitely clear vegetable(obtusin), bluntness a leaf definitely clear vegetable(obtusifolin) and its saponin type.
三、The effect of Cassia Seed ::
According to 《Chinese Herbal Materia Medica 》jot down, Cassiae Torae Semen again"human body street cleaner", the attribute is gentle, having sticky liquid quality, protein, fat oil, greatly yellow sour, greatly yellow vegetable, also have vitamin A, carotenoid.

The men and women are old and few to all suit to drink, having anger of leak and backing the effect of large intestine fire, can promote the appetite way digest, the clearance Xiu expels the toxin stored inside human body then, so someone think it has result of easing the weight.

Clear eyes, counteract poison also is the Cassiae Torae Semen main effect.

The Cassiae Torae Semen is applicable to:
Sit the person of reading or computer to use regularly to the long-term, produce the person of[with] tired feeling easily

Lack of a flexibility exercise chance while working, and muscle easily sore person

The person, neck and shoulder bone that the eyestrain, brain nerve draws tight I am often aching to draw tight of person

The belly has flatulence, or while developing period pimple the person of the full with face

Take much definitely clear alleviate to the above condition of illness, all have very big of help

The pharmacology function of Cassiae Torae Semen
The Chinese medicine thinks the Cassiae Torae Semen has
1. Pure liver clear eyes
2. The smooth bowel relaxs bowel
3. The benefit urines
4. Decline blood pressure
5. Anti- cause microorganism
6. Reduce serum cholesterol(Cholesterol) with the function of triglyceride(TG),
Accelerate womb constringency and have already urged to produce a function.

【Dosage usage 】
5~15 gram.Can't be long to fry while breaking into piece decoction, being used for relaxing bowel.

蒽醌

2008-04-07T20:37:00.000-07:00

http://zh.wikipedia.org/wiki/%E8%92%BD%E9%86%8C
蒽醌（Anthraquinone，化學式：C14H8O2），又譯安特拉歸農，是一種醌類化學物。蒽醌的複合物存在於天然，也可以人工合成。工業上，不少染料都是以蒽醌作基體；而不少有醫療功效的藥用植物，如蘆薈，都含有蒽醌複合物。例如蘆薈的凝膠當中的蒽醌複合物，有消炎、消腫、止痛、止癢及抑制細菌生長的效用，可作天然的治傷藥用。此外，利用蒽醌的蒽醌法是生產雙氧水的最佳方法。
物理特性與化學特性
蒽醌不能溶於水，但可溶於乙醇、硝基苯、苯胺和醚。在正常情況下較穩定。
天然來源
蒽醌可在蘆薈（Aloe）、大黃、番瀉葉（Senna）、美鼠李（Rhamnus purshiana）、真菌、地衣和昆蟲身上發現。通常以色素的形式存在，部份天然蒽醌的衍生物具導瀉作用。

名稱
蒽醌
化學式
C14H8O2
IUPAC命名法
9,10-(9,10-二氢合蒽)二酮
CAS登录号
[57-55-6]
外觀
黃色或帶光澤灰綠色固體
相態
固態
摩爾質量
208.23 g/mol
熔點
286 °C
沸點
379.8 °C
溶解度
不溶於水,可溶於乙醇,硝基苯,苯胺,醚

Phase equilibrium analyzer

2008-01-22T04:41:00.001-08:00

Rapid, Automated Solubility and Phase Behavior Studies

Thar's Phase Equilibrium Analyzer is likely the most automated and sophisticated in the world. The system includes a cutting edge PC controlled vessel system that allows the user to control pressure, temperature and density. Simple to use and install, the motorized variable volume vessel combines with a PC-controlled high pressure syringe pump, camera system, heating bath, TV/VCR and PC with Thar software to create a turnkey solution. Many scientists and managers are curious as to how products react, crystallize, mix, disperse and dissolve in supercritical media. For them, the solution is the Thar PEA.

Advantages:

■ Rapid generation of solubility data

■ Ideal for process development

■ No extraction efficiency issues

■ No collection issues

■ New insights into the mechanism

■ Data logging during the process

■ Only H.P. Viewing Instrument with automated, moving plunger with an attached agitator

Benefits:

■ Helpful for studying GAS (Gas Anti-Solvent Precipitation Technique

■ SAS simulations possible (Supercritical Anti-Solvent)

■ Useful in studying how surfactants and solvents behave under pressure

■ Viewing reactions, dissolutions, crystallization

■ Rapidly saves time on process scale-up

http://www.thartech.com/

Magnetic Tunnel Junction

2008-01-15T20:13:00.001-08:00

A magnetic tunnel junction (MTJ) consists of two layers of magnetic metal, such as cobalt-iron, separated by an ultrathin layer of insulator, typically aluminum oxide with a thickness of about 1 nm. The insulating layer is so thin that electrons can tunnel through the barrier if a bias voltage is applied between the two metal electrodes. In MTJs the tunneling current depends on the relative orientation of magnetizations of the two ferromagnetic layers, which can be changed by an applied magnetic field. This phenomenon is called tunneling magnetoresistance (TMR).

Nowadays MTJs that are based on transition-metal ferromagnets and Al₂O₃ barriers can be fabricated with reproducible characteristics and with TMR values up to 50% at room temperature. Recently large values of TMR observed in crystalline MTJs with MgO barriers further boosted interest in spin dependent tunneling. MTJs are promising for applications in magnetic storage and sensor industry.

http://physics.unl.edu/~tsymbal/tsymbal_files/TMR/sdt_files/page0001.html

Bio-functionalized of Monodisperse Magnetic Nanoparticles and Their Use as Biomolecular Lables in a Magnetic Tunnel Junction Based Sensor

2008-01-14T02:20:00.001-08:00

Stephanine G. Grancharov, Hao Zeng, Shouheng Sun, Shan X. Wang, Stephen O'Brien, C. B. Murray, J. R. Kirtley, and G. A. Held

J. Phys. Chem. B
2005, 109, 13030-13035

Abstract : NPs(monodisperse magnetic nanoparticles)能以超靈敏磁性來偵測生物分析物，然而要使這些粒子有生物相容性是一個挑戰。我們報導12nm錳鐵NPs的生物功能性及偵測，能在卵白素二氧化矽基材及互補DNA二氧化矽基材上獲得有位置特異性鍵結的維生素H功能性NPs。利用掃描式SQUID顯微鏡，顯示那些與基材結合的NPs仍具有磁性，示範了一種在室溫使用NPs及適用於垂直磁場的磁性穿隧接點生物感測器(magnetic tunnel-junction-based biosensor)來檢測蛋白質鍵結或DNA雜交的新方法。

SQUID－大倫學長整理

2008-01-10T22:18:00.001-08:00

SQUID2a.JPG

SQUID2b.JPG

Gmix.JPG

Gzero.JPG

Dear 筱沁,

附件是重新處理過的 SQUID 數據並且將結果與千惠的結果比對

圖2b 的結果合理，說明此次量測儀器應無異常, 隨溫度增加其飽和磁量會下降 ( 2.3 -> 0.7~0.3)

比對千惠的之雜交後之結果，飽和磁量下降頗多，有幾個可能：

(1) 取出之樣品中MNP的濃度偏低

(2) 雜交之結果顯著抑制了飽和磁量

(3) 系統性偏差

屏除第三點暫且不論，假設(2)成立則殘磁量亦應隨之增加

比對圖2b則殘磁反倒下降一個數量級 (~6e-3)

這個結果則印證假設一比較可能成立。

結論：妳跟我說你的步驟，妳在旁邊看我有沒有重覆錯誤，我來重作一次，之後重新送一次分析，連同空白

若有任何想法，煩請與我連絡

大倫

Density Measurement of Polymer/CO2 Single-Phase Solution at High Temperature and Pressure using a Gravimetric Method

2008-01-04T00:33:00.001-08:00

Euta Funami, Kentaro Taki, Masahiro Ohshima

Department of chemical Engineering, Kyoto University Japan, Kyoto, Japan 615-8510

Journal of Applied Polymer Science, Vol. 105, 3060-3068(2007)

ABSTRACT:

在高於聚合物熔點的溫度以及CO2壓力範圍0~15MPa，使用新提出的重力測量法量測聚合物/CO2單相溶液的密度。在高壓CO2下，使用磁懸浮天平(magnetic suspension balance, MSB)量測密度：一薄盤狀鉑板被浸入盛有聚合物/CO2單相溶液的MSB高壓室。將吸收室保持CO2壓力及溫度下測板重，因為聚合物/CO2單相溶液對板子施浮力而使板子重量減輕，即可從板子重量的差值算出聚合物/CO2單相溶液的密度。實驗結果顯示，PE/CP2溶液的密度隨CO2壓力上升而增加，而PEG/CO2溶液的密度則隨CO2壓力上升而減少。為了將CO2溶解於聚合物的效應以及機械壓力的效應區別開來，比較聚合物/CO2溶液的密度與承受機械壓力的純聚合物密度(以Sanchez-Lacombe 狀態方程式以及聚合物的壓力-體積-溫度資料來計算)。比較結果可以說明CO2溶解於聚合物會減少PEG/CO2及PE/CO2系統的密度，但兩者減少的程度不同。

重力測量法

2008-01-03T23:34:00.000-08:00

重力測量法(力學測量法)：利用自由落體公式(S=1/2 G T2 其中G為重力加速度，大約為9.8 公尺/秒平方；T為物體自由落下所需時間，單位為秒)，在高處自由投下一物體，利用其落下花費時間，估算出所在處高度。
http://www.ied.edu.hk/apfslt/v5_issue2/chencc/chencc4.htm