乙酸的

The preparation of polymer is required for high purity of glycolic acid, if not, low-weight polymer is obtained, therefore, high purity glycolic acid is scarce in the market. So, the research for the synthesis of glycolic acid is essential. In domestic and overseas, there are many methods for preparation of glycolic acid, including glycin oxidation, cyanogenesis, aldehyde oxidation, coupling of maldehyde and methyl formate, oxalic acid electrolysis, chloroactic acid hydrolysis and so on.

制备羟基乙酸的聚合物时，对羟基乙酸单体的纯度要求较高，否则得到的聚合物分子量较低，导致高纯度羟基乙酸的需求量逐年增长，目前在国内，高纯度的羟基乙酸还没有形成工业化规模生产，对羟基乙酸的合成进行研究是非常有意义的。

N-methylacetamide was used as entrainer in separating acetic acid from water with extractive distillation ,and the interaction mechanism in this process was studied by using the density functional theory.

文献[1-4]认为萃取精馏分离乙酸水溶液过程中萃取剂与乙酸之间的氢键作用改变了溶液中乙酸和水的活度系数关系，从而改变了两者之间的相对挥发度，使得水和乙酸的分离变得相对容易。

Chloroacetic acid is a very important intermediate of Pharmaceuticals, dyes, pesticides, cellulose derivatives.

为了控制二氯乙酸的生成，降低氯乙酸的物料消耗，本论文采用连续法合成氯乙酸。

The investigation on the concentration of four haloacetic acid s during conventional water treatment process in waterworks and in drinking waters in North China showed that there were only dichloroacetic acids and trichloroacetic acids in waters,and the proportion of TCAA was from 52% to 90%.

对北方某自来水厂常规水处理过程及饮用水体中的4种卤乙酸质量浓度进行了调查，结果表明水体中只存在二氯乙酸和三氯乙酸，其中三氯乙酸所占比例较大，为52%~90%；常规水处理工艺对二氯乙酸有较为明显的去除效果，去除率在15%以上，而对三氯乙酸没有明显的去除效果，但总体而言其对卤乙酸有10%左右的去除率；预氯化对卤乙酸的产生起主导性作用，该处产生的卤乙酸占整个氯化过程产生的卤乙酸总量的60%以上，因此常规工艺有必要从预氯化工艺着手加以改进，来更好的控制卤乙酸的产生量。

The amount of hydroxyacetic acid , equal to that of sodium chloride, produced from chloroacetice acid hydrolysis is determined by adopting Moore method and there fore the ratio of transformation of chloroacetice acid hydrolyzed can be calculated.

氯乙酸水解生产羟基乙酸的工艺过程中产生等物质量的氯化钠，采用莫尔法测定氯乙酸水解的产物氯化钠，并计算氯乙酸的水解转化率，从而选择和控制水解反应的条件。

The review highlights the technical developments in the identification,quantification and separation of α-hydroxyacetic acid,especially solvent extraction and synergistic extraction.

文章比较了各种羟基乙酸定性及定量分析方法，综述了羟基乙酸分离方法，特别是溶剂萃取和协同萃取效应。最后，分析了羟基乙酸的开发前景。

The experimental results showed that, monochloroacetic acid and dichloroacetic acid enhanced photocatalytic hydrogen generation activity, but trichloroacetic acid did not improve it. The amount of produced H_2 increases almost proportionally to the irradiation time within 5 h irradiation. The photocatalytic oxidation of monochloroacetic acid and dichloroacetic acid mainly produced CO_2, HC1 and CH_2O, the photocatalytic oxidation of trichloroacetic acid mainly produced CO_2 and HCl.

实验表明，一氯乙酸、二氯乙酸的存在明显地提高了制氢反应效率，而三氯乙酸的存在却不能起到促进作用；反应5h内，反应生成氢的量与反应时间成线性关系；一氯乙酸、二氯乙酸光降解产物主要是CO_2、HCl和CH_2O，三氯乙酸光降解产物主要是CO_2和HCl；研究了溶液pH值对放氢反应的影响；在实验浓度范围内，一氯乙酸、二氯乙酸浓度对放氢反应的影响，表观上符合Langmuir-Hinshelwood关系式；考察了一氯乙酸、二氯乙酸在光催化剂表面的吸附。

Water samples were extracted and purified and collected by solid-phase extraction LC-18 column. Soil samples were extracted by ethyl acetate/petroleum ether (2:1, by vol) and purified by sulphonation. Wheat sample was extracted by acetonitrile/water (4:1, by vol) and purified and collected by SPE- Florisil column.

水样直接用LC-18固相萃取小柱分离、净化和富集；采用乙酸乙酯／石油醚（体积比2：1）振荡提取，磺化法净化，测定土壤中氯氟吡氧乙酸残留量；以乙腈／水（体积比4：1）为提取剂，氟罗里硅土固相萃取小柱分离、净化，测定小麦样品中氯氟吡氧乙酸的残留量。

Results showed that extraction abilities depends on the hydrophobic of solutes which pK〓 values are similar, e. g. acetic, propionic, butyric and valeric acids, while pK〓 values affect dominantly the extraction abilities of acids with similar hydrophobic, e. g. formic, acetic, chloroacetic, dichloroacetic, and trichloroacetic acids. Meanwhile, diluents and TOA concentration also affect the extraction equilibria of acids through the specific basicity of TOA .

TOA对酸性差别很小的一元羧酸如乙酸、丙酸、丁酸、戊酸的萃取能力主要取决于羧酸的疏水性参数logP；TOA对疏水性参数差别较小的羧酸如甲酸、乙酸、一氯乙酸、二氯乙酸、三氯乙酸的萃取能力主要取决于羧酸的电性参数；稀释剂的种类、TOA的浓度都会影响TOA的表观碱度pH〓，并通过TOA的表观碱度影响羧酸的萃取平衡。

The long-term and short-term effects of different propionic/acetic acid ratio and initial pH on the anaerobic and aerobic transformations of GAOs were studied.

2在丙酸和乙酸的碳摩尔浓度相同的情况下，GAOs吸收乙酸的速率较快，且在乙酸浓度适宜的情况下，GAOs对乙酸的吸收不需要长期驯化，短期提高进水中的丙酸量可抑制GAOs的生长。

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。