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
2008年5月16日 星期五
綠色化學的 12 基本法則
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
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)
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
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
2008年4月11日 星期五
微波萃取技术在天然产物提取中的应用
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。
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。
2008年4月8日 星期二
降脂灵片中决明子定性和定量分析方法的研究
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
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
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
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
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Ｃａｓ ｓｉａｏｂｔｕｓｉｆｏｌｉａＬ。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－ｔ ｏｎｅ）及２个新内酯：异决明子内酯（ｉｓｔｏｌａｃｔｏｎｅ）和ｃａｓｓｉａｌａｃｔｏｎ ｅ，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１ ０ｍｇ／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９ ｇ，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１５ ｇ，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
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Ｃａｓ ｓｉａｏｂｔｕｓｉｆｏｌｉａＬ。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－ｔ ｏｎｅ）及２个新内酯：异决明子内酯（ｉｓｔｏｌａｃｔｏｎｅ）和ｃａｓｓｉａｌａｃｔｏｎ ｅ，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１ ０ｍｇ／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９ ｇ，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１５ ｇ，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
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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》）
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
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.
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
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
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
2008年1月22日 星期二
Phase equilibrium analyzer
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/
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/
2008年1月16日 星期三
Magnetic Tunnel Junction
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
2008年1月14日 星期一
Bio-functionalized of Monodisperse Magnetic Nanoparticles and Their Use as Biomolecular Lables in a Magnetic Tunnel Junction Based Sensor
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。
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。
2008年1月11日 星期五
SQUID－大倫學長整理
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
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
2008年1月4日 星期五
Density Measurement of Polymer/CO2 Single-Phase Solution at High Temperature and Pressure using a Gravimetric Method
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
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
http://www.ied.edu.hk/apfslt/v5_issue2/chencc/chencc4.htm
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