酯化作用

The results indicate that improving temperature to reflux, using low polarity solvent as dispersion medium and proper molar ratio of tetrabutyl titanate to stearic acid can bring out good modification. The function of tetrabutyl titanate is to react with the surface hydroxyl groups and adsorbed H2O on the powder particles to produce new binding sites such as M—O—Ti—OC4H9and M—O—Ti—OH, which can easily react with the carboxylic acid. As temperature increases from room temperature to reflux temperature, the reactions between RCOO- and Ti change from coordinate bonds to covalent bonds, which makes the carbon chains of stearic acids more strongly bound with the powder particles surface.

研究结果表明，提高处理温度、适当增加复合改性剂中硬脂酸的量并选用极性弱的有机溶剂可达到比较理想的改性效果；钛酸四丁酯的作用是与粉体粒子表面的羟基以及吸附水反应产生偶联点，如M—O—Ti—OH，这些偶联点易于与羧酸反应；在低温时RCOO-与偶联点的Ti之间以配合物的形式发生作用，在回流温度下处理时，主要发生酯化反应，使硬脂酸更牢固地嫁接到粉体粒子表面，改性效果更好。

On the basis of MEBT, a new technique hypothesis of injecting MEBO under the eschar was proposed to have 6 biochemical reactions available, such as hydrolysis, enzymolysis, saponification, rancidify, lipofication, esterification of MEBO with necrotic tissue of the eschar, then to realize liquefaction and quick defluxion of necrotic tissues, This finally to play a role of regenerative action of MEBO in situ to turn potential regenerative cells into skin stem cells that would further proliferate and differentiate to form skin tissues, reaching the goal of physiologically repairing wounds.

最后提出了在烧伤湿性医疗技术正规治疗的基础上，同时进行痂下注射MEBO的新技术设想，其目的是使痂下组织尽早接受MEBO的治疗，痂下发挥MEBO的水解、酶解、皂化、酸败、脂化、酯化六大生物化学反应，促使坏死组织痂下痂外一起液化，尽快脱落；而且在痂下发挥MEBO原位再生作用，使潜能细胞转变成皮肤干细胞，干细胞进一步增殖分化形成皮肤组织，达到创面生理性修复之目的。

Compared with the previous method, the improved route can provide directly a spheroid form of immobilized lipase particles of which the size can be controlled by adding non-ionic surfactants during the preparation process so as to increase the recovery rate of enzyme as well as decrease the external diffusional restriction which can diminish the enzyme activity. The improved method can also alter the hydrophobicity and microstructure of the immobilized enzyme matrix by changing the molar ratios of different alkoxyl silanes so as to enhance the enzyme activity by a"surface active effect"and eliminating the internal diffusional restriction.

与前人的制备方法相比，改进的方法可直接制得球形的固定化酶颗粒，而且颗粒的大小可以通过在制备过程中加入非离子型表面活性剂加以控制，从而可以提高固定化过程的酶活回收率和减小外扩散效应对酶的表观催化活力的影响；改进的方法还可以通过改变原料硅氧烷的种类及配比来改变最终制得的固定化载体的疏水性质及微观结构，从而通过对脂肪酶的&界面活化&作用和减小内扩散效应提高固定化脂肪酶的表观酯化活力。

Bornyl oxalate was formed smoothly by esterification of β-pinene with anhydrous oxalic acid using solid superacid as catalyst. Borneol was obtained by saponification of bornyl oxalate with NaOH solution.

在固体超强酸催化作用下β-蒎烯和无水草酸平稳地发生酯化反应，生成草酸龙脑酯；加入氢氧化钠溶液发生皂化反应得到龙脑。

Synthesis of cyclohexyl acetate with rare earth composite solid superacid catalyst of SO2-4/TiO2/Ce4+was investigated.

研究了以稀土复合固体超强酸SO42-/TiO2/Ce4+为催化剂合成乙酸环己酯的反应，在反应温度分别为100℃、110℃、120℃下，测出酯化反应的动力学参数，建立了动力学方程，并与无催化剂作用下合成乙酸环己酯反应的活化能及动力学方程进行了比较。

The effect of reaction timcxreaction temperaturexpH and citrate concentration on the esterify process were discussed.

柠檬酸酯淀粉是一种具有抗性作用酯化变性淀粉，在国外广泛应用于面包、饼干及其它食品中，以改善食品品质。

The reaction of 4-bromaophenol and geranic acid in the presecnce of p-TsOH afforded 4-bromophenolα-cyclogeranoate in which cyclization of geranic acid toα-cyclogeranic acid was followed by esterification ofα-cyclogeranic acid with p-bromophenol.

对溴苯酚与香叶酸在p-TsOH催化作用下发生了香叶酸向α-环香叶酸环化、α-环香叶酸环与对溴苯酚的酯化，得到了唯一产物α-环香叶酸对溴苯酯，产率68%。

Macrocycle with one pyridyl unit and one aryl oxdiazole unitCondensation of Ts-amino acids with 2,6-bishydroxymethyl pyridinegave di-esters in the presence of DCC and TsOH in pyridine. DMAP,another acylation catalyst was also discussed in our esterification.

二。含一个吡啶环和一个二苯基噁二唑单元：直接采用Ts保护的氨基酸与吡啶二醇在吡啶-TsOH反应体系中，在DCC作用下生成吡啶二醇二酯，讨论了酯化过程中不同酰基化试剂的应用。

The repeated using and catalytic activity of these solid acid catalysts have been studied in the synthesis of biodiesel using acidified soybean oil as raw material.

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。

Cellulose acetate butyrate,which is widely applied as coatings additive, is synthesized in the heterogeneous system. The activation is required because of the strong hydrogen intramolecular and intermolecular bondings and the regulation of the crystalline region in cellulose microfibrils.

中文摘要纤维素醋酸丁酸酯（Cellulose acetate butyrate是一种广泛应用于涂料工业的添加剂，由于纤维素具有分子内与分子间强氢键作用以及纤维素纤维的局部规整的结晶序列等特征，一般纤维素在酯化反应前都需要进行预活化处理，工业上纤维素醋酸丁酸酯的合成方法一般都在非均相体系中进行的。

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。