酯化作用

Then Doripenem came into the market in the July ,2005. We studied the synthesis of Doripemen.Firstly, we synthesized the chemical 2 from the starting material------o-hydroxylphenylacylamine through Reformastky reaction, alkylation, Diekmann reaction, enolization, esterification and etc. Secondly, we synthesized the chemical 3 from L — hydroxylproline through the protection of carboxyl, amidogen and hydroxyl group, reduction by NaBr, SN_2 substitution and Mitsumobu reaction.

我们以水杨酰胺为起始原料，经Reformatsky反应、烷基化、Diekmann环合、烯醇化、酯化等反应合成双环母核2；再从L-羟基脯氨酸出发，经酯化保护羧基、保护氨基、保护羟基、硼氢化还原酯得醇、Sn2取代和Mitsumobu反应等合成巯基侧链3；最后由化合物3经脱保护、水解得硫醇，和化合物2在二异丙基乙基胺的作用下缩合，最后Pd／C催化脱保护，历经16步反应最终得到产物多尼培南。

The catalytic effect of different modified molecular si eves were studied for synthesis amyl acetate, the results indicate that SO 2- 4 /FeZSM have go od catalysis activity to esterification .The effect of the ratio of reactants, the amoun t of the catalyst and the reaction time were also investigated.

考察不同改性分子筛催化合成乙酸戊酯的催化活性，结果表明：改性SO2 - 4/FeZSM对合成酯的催化作用较好，并讨论了以该催化剂催化酯化时原料配比、催化剂用量、反应时间等因素与酯化反应的关系。

The results showed that temperature rise would inhibit their esterification capacity, ethyl caproate-producing capability of raw zymin of 1# high-temperature monascus improved with the prolong of the esterification time when ethanol concentration was 4 %vol and caproic acid content was 4 mL, and when ethanol concentration and caproic acid content was within proper range, caproic acid content had more effects on the formation of ethyl caproate by raw zymin than ethanol concentration.

结果表明，温度相对升高对其酯化力的形成有一定的抑制作用；高温型红曲1#酯化菌株粗酶制剂的酯化力在乙醇浓度为4 %vol、己酸含量为4 mL时，产生己酸乙酯的能力随酯化时间的延长而增强；在适宜的乙醇浓度和己酸含量范围内，己酸含量对酯化酶粗酶制剂己酸乙酯生成影响比乙醇含量的影响大。

After esterification, the ethyl-2-chloro-3-phenylpropionate reacts with diethyl malonate under the catalysis of sodium ethylate, and we obtain the corresponding triethyl ester. The-benzylsuccinic acid is formed by the triethyl ester reacting with concentrate hydrochloric acid and taking place hydrolyzation and decarboxylation reaction at the same time. In order to avoid the formation of cinnamic acid, the sodium ethylate and diethyl malonate must be react sufficiently. The course has simple operation, inexpensive materials and better yield.

具体制备工艺为：首先以L-苯丙氨酸为原料采用重氮化方法得到-2-氯-3-苯基丙酸，再经酯化得到-2-氯-3-苯基丙酸乙酯后在乙醇钠催化作用下和丙二酸二乙酯缩合，发生SN2反应，得到相应的三乙酯，然后经水解和脱羧，得到-苄基丁二酸；在实验中乙醇钠要和丙二酸二乙酯充分反应，避免生成肉桂酸乙酯；该过程操作简单，原料便宜，产率较高，总收率可达到26.8%。

We prepared the pyrethric acid II through four reactions: esterification, oxidation, decomposition, diesterification. And the original synthesis route of the pyrethric acidII was improved: the yield of oxidation of allyl rise through increasing the activity of Selenium dioxide; in the document, tert-butyl-trans -2, 2-dimethy1-3-(2"-methoxycarbony1-1"-propenyl)cyclopropanecarboxy late was synthesized from tert-butyl-trans-2,2-dimethyl-3-(2 -formyl-r -propenyl) cyclopropanecarboxylate with two steps, with low yield.

我们经过酯化，氧化，成双酯，热分解四步反应，成功地得到了第二菊酸，并改进了原第二菊酸的合成路线：通过改变二氧化硒的活性提高了烯丙甲基的氧化产率；将原路线中醛氧化成羧酸、羧酸酯化的两步反应改为醛和甲醇、二氧化锰等作用一步直接酯化的方法，减少了反应步骤，提高了总收率。

Esterification process of a reversible step wereresolved as two irreversible steps,then chemical decomposition of wood components weredecreased in liquid acid catalyst.Experiments showed that crosslinking catalysts took catalysisrole on two process in the esterification,(1)five cyclic anhydrides formed by dehydration ofpolycarboxylic acids,(2)esters occurred by substitution between five cyclic anhydrides andwood.

实验中的反应过程使一般的酯化一步可逆反应，分解为两步不可逆反应，减少了液相酸催化过程的木材组分化学降解；交联反应催化剂对于多元羧酸类化合物与木材组分的酯化反应具有两个过程的催化作用：(1)多元羧酸脱水形成五元环酸酐中间体；(2)木材与五元酸酐中间体亲核取代反应形成酯。

The esterifying effects of monascus, daqu and rhizopus strain on single acid (acetic acid, caproic acid, lactic acid, butyric acid) and mixed acid (acetic acid,caproic acid,lactic acid, and butyric acid mixed together according to the ratio of 1∶1∶1∶1) were studied.

对红曲霉、大曲以及根霉菌对单一酸（乙酸、己酸、乳酸、丁酸）和混合酸（四大酸按1∶1∶1∶1混合）的酯化效果进行了研究，结果表明，红曲霉能促进己酸、丁酸及混合酸与乙醇的酯化作用，生成的酯类物质均为己酸乙酯，而且酯化能力极强；大曲能促进己酸、丁酸及混合酸与乙醇的酯化作用，生成的酯类物质均为己酸乙酯，并且能促进乙酸与乙醇的酯化生成乙酸乙酯；根霉能促进己酸和混合酸与乙醇的酯化作用，生成少量的己酸乙酯和乳酸乙酯。

Tetrachloroterephthalic acid was prepared by chlorinating terephthalic acid, oleumsolvent and iodine catalyst. Tetrachloroterephthalic acid was acylated by sulphurous oxychloride in the presence of DMF to form tetrachloroterephthaloyl chloride. The acyl chloride product was fluorinated by potassium fluoride and esterified by methanol to synthesize dimethyl tetrafluoroterephthalate. The ester was reduced with potassium borohydride and lithium chloride to give tetrafluoroterephthalyl alcohol. The above product was bromated in the hydrobromic acid to obtain 4-bromomethyl-2,3,5,6-tetrafluoro-benzene methanol. 4-Methyl-2,3,5,-6-tetrafluorobenzene ethanol was obtained by reducing the bromide with magnesium. In the exist of DCC and DMAP, tefluthrin was got by the condensation reaction between 4-methyl-2,3,5,6-tetrafluoro-benzene methanol and-(1RS,3RS)- 3-(2- chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethyl cycolpropanecar-boxylate acid.

对苯二甲酸与氯气在碘存在下以发烟硫酸为溶剂进行氯化制备四氯对苯二甲酸；再以DMF为催化剂与二氯亚砜反应生成四氯对苯二甲酰氯；以氟化钾为氟化剂，环丁砜为溶剂置换氟化，再与甲醇酯化得到四氟对苯二甲酸甲酯；以KBH4-LiCl为还原剂二甲醚为溶剂反应制得四氟对苯二甲基苄醇；以氯苯为溶剂在溴化氢溶液中溴化得到溴化产物；在乙醇溶液中经镁粉还原得到4-甲基-2，3，5，6-四氟苄醇；甲基苄醇与功夫酸在催化剂二环己基碳二亚胺和4-二甲氨基吡啶作用下缩合得到七氟菊酯，总收率达43.6%。

Experiment on the transesterification and esterification of acidified soybean oil has been studied.

试验研究了大豆酸化油在复合酸催化剂的作用下与甲醇发生转酯化和酯化反应生成脂肪酸甲酯的最佳反应条件。

Triacylglyceride An ester of glycerol in which all the-OH groups are esterified; the acyl groups may be the same or different.

三酰甘油酯：甘油的所有三个-OH 都发生酯化作用，而酰基可发生变化或保持不变而得到的酯。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。