乙酸甲酯

Acid catalyst and H + catalysis in the acid catalysts were studied for synthesis of methyl glycolate via coupling of methyl formate and trioxane in a microform high-pressure autoclave(120mL).

在微型高压反应釜中(12 0ml)，考察了酸催化三聚甲醛和甲酸甲酯制备羟基乙酸甲酯的偶联反应，并对酸催化剂中H+的作用进行了研究。

In order to test the validity of this method, the saponification of methyl acetate, ethyl formate and methyl formate in aqueous solution at 25℃ has been studied.

研究了25℃下乙酸甲酯、甲酸乙酯和甲酸甲酯在水溶液中的皂化反应，其计算结果与文献值相吻合，从而验证了热弛豫法的正确性。

A novel route for synthesis of methyl acetoacetate from acetone and dimethyl carbonate over solid base catalysts was proposed.

以碳酸二甲酯与丙酮为原料，在固体碱上合成乙酰乙酸甲酯，并考察了反应温度、反应时间、催化剂用量和原料摩尔比等因素对反应结果的影响。

A series of methyl 2,7,7-trimethyl-5-oxo-4-aryl1,4,5,6,7,8- hexahydroquinoline -3-carboxylate were synthesized by the reaction of aromatic aldehydes,dimedone and methyl acetoacetate using ammonium acetate as catalyst in glycol under microwave irradiation with 82%～98% yields in 4～6 min.

微波辐射下以芳醛、达咪酮、乙酰乙酸甲酯为原料，乙二醇为溶剂，醋酸铵为催化剂合成了一系列2，7，7-三甲基-5-氧代-4-芳基-1，4，5，6，7，8-六氢喹啉-3-羧酸甲酯化合物，反应时间4~6 min，产率82%~98%。

Firstly, 3-ethylthiobutanal was prepared from crotonaldehyde reacting with ethanehiol in triethylamine with high yield. Secondly, methyl acetoacetate was converted to 6-ethylthiohept-3-en-2-one by three steps via hydrolysis, condensation with 3-ethyltio-butanal and dehydration, then 6-ethylthiohept-3-en-2-one was cycloco ndensed with dimethyl malonate by Michael addition and Claisen condensation, followed by saponification and decarboxylation to give the intermediate of 5-(2-ethylthiopropyl)-cyclohexane-1,3-dione.

首先，以巴豆醛与乙硫醇为原料，在三乙胺的催化作用下高收率制得3-乙硫基丁醛；然后从乙酰乙酸甲酯出发，通过碱水解、与3-乙硫基丁醛缩合、脱水三步反应合成6-乙硫基-3-烯-2-庚酮，接着6-乙硫基-3-烯-2-庚酮与丙二酸二甲酯通过Michael加成和Claisen缩合成环，再通过皂化和脱羧反应生成中间体5-[2-丙基]-1，3-环己二酮；再与丙酸酐反应丙酰化，最后与0-3-氯-2-丙烯基羟胺肟化，得到目标化合物烯草酮。

Our main products include 5-Methyl-2-pyrazinecarboxylic acid series, Guanine series, Folic acid series, Methyl Cyanoacetate and Ethyl cyanoacetate series, we also have made great contribution in the development of cardiovascular drug, stomach drug, anti-inflammatory drug and antidepressants, such as Nizatidine, Acipimox, Glipizide, Zaltoprofen and Pregabalin, which have been put into production on large scare.

公司主要产品有5-甲基吡嗪-2-羧酸系列，鸟嘌呤系列，叶酸，氰乙酸甲酯，氰乙酸乙酯系列，在心血管药、胃药、消炎药、抗抑郁药等新品开发上有重大建树，先后研制成功，形成批量生产，如尼扎替丁、阿西莫斯、格列吡嗪、扎托洛芬、普瑞巴林，同时具备为客户定制化学品的能力。

In order to investigate the mechanism for this reac-tion, methyl α-bromoacetate or ethyl α-bromoacetate as starting material was added to the solution of phenyl selenoamide in ethanol in 1∶1 or 2∶1 molar ratio under the neutral condition at room temperature. The results indicated that the same product bis or bis diselenide was formed. Byproduct ethyl benzoate was also separated.

为了研究该反应机理，选择α-溴代乙酸甲酯或α-溴代乙酸乙酯在无催化剂、中性条件下，乙醇溶液中与苯基硒代酰胺室温下反应，投料比为1∶1和2∶1，结果也都生成了同一类产物二甲氧羰基甲基二硒醚或二乙氧羰基甲基二硒醚，同时还分离得到了相应的副产物苯甲酸乙酯。

In order to investigate the mechanism for this reaction, methyl α-bromoacetate or ethyl α-bromoacetate as starting material was added to the solution of phenyl selenoamide in ethanol in 1:1 or 2:1 molar ratio under the neutral condition at room temperature. The results indicated that the same product bis or bis diselenide was formed. Byproduct ethyl benzoate was also separated.

为了研究该反应机理，选择α-溴代乙酸甲酯或α-溴代乙酸乙酯在无催化剂、中性条件下，乙醇溶液中与苯基硒代酰胺室温下反应，投料比为1：1和2：1，结果也都生成了同一类产物二甲氧羰基甲基二硒醚或二乙氧羰基甲基二硒醚，同时还分离得到了相应的副产物苯甲酸乙酯。

Then, the multidentate amine immobilized on silica gel was used as ligand for CuCl in ATRA of CCl_4 with MMA and methyl trichloroacetate with St repeatly. The conversion and purity of the product were determined through the gas chromatography and ~1H NMR respectively. Finally, the multidentate amine immobilized on silica gel was used as ligand for CuCl in ATRP of St initiated by TCPP and MMA initiated by MMTCB. The number average molecular weights of the polymers were determined through GPC.

此多齿胺改性硅胶配体被分别多次重复用于四氯化碳与甲基丙烯酸甲酯，三氯乙酸甲酯与苯乙烯的ATRA反应中，通过气相色谱测定了原料的转化率随时间的变化，且通过核磁~1H NMR测定了产物的纯度，我们还进一步将此种多齿胺改性硅胶配体用于TCPP引发St的ATRP和MMTCB引发MMA的ATRP反应中，通过GPC测定所得聚合物的分子量。

In the third step, when the ratio of racemic ester to benzenesulfonyl chloride to triethylamine to catalyst 4-DMAP is 1:1:1:0.1 in 10℃, the yield is 82.9% and high purity is obtained by crystallisation.

在第三步磺酰化反应中，得到合成消旋2-苯磺酸基-2(2-氯苯基)乙酸甲酯的较佳反应条件为邻氯扁桃酸甲酯：苯磺酰氯：三乙胺=1：1：1，催化剂4-DMAP用量为摩尔反应物的10%，反应温度为10℃，收率为82.9%，同时用结晶方法获得高纯度的产物。

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。