查询词典 methyl-glyoxal

The most preferable substituents are methyl groups for positions R1 and/or R2, due to the existence of a hyperconjugation effect between the p z orbital of the central carbon atom and one of the C—H bond orbitals in methyl group.

当R1， R2位置是甲基时，由于碳原子的p z 轨道与甲基的一个C—H键轨道间存在强的超共轭效应，从而可以较大程度地降低α-氢转移反应的势垒。

Meanwhile,the factors which affected the drying were also analyzed including the flow rate of methyl chloride ,the content of isobutylene,the amount of regenerated nitrogen,the regeneration time,the discharging condition of methyl chloride remaining in tower before regeneration,the using time of Al_2O_3,and so on.

研究了丁基橡胶装置干燥塔的干燥、再生过程，对影响干燥效果的主要因素如氯甲烷流量、异丁烯含量、再生氮气量、再生时间、再生前塔内残留氯甲烷的排放程度、干燥剂Al_2O_3的使用时间等进行了分析。

The concentrations of isopentane, 2-methyl-pentane, pentane and 3-methyl-pentane which are from automobile exhaust and gasoline evaporation were highest in alkanes. Benzene/toluene ratio was close to 0.5 which is the characteristic value of automobile exhaust. The concentrations of pinene and isoprene were highest in alkenes.

烷烃类物质中异戊烷、2-甲基戊烷、正戊烷和3-甲基戊烷等机动车尾气或汽油挥发特征性物质浓度最高；芳香烃类物质中苯／甲苯的特征比值略高于机动车尾气排放特征比值0.5；烯烃类物质以植物排放的蒎烯、异戊二烯为主。

Under the catalyst, the polymerization retarder, the including water medicinal preparation existence condition, the methylacrylic acid and the polyethylene glycol single methyl ether (400) direct esterification synthesis methylacrylic acid polyethylene glycol single methyl ether (400) ester, and the influence factors of the catalyst, polymerization retarder, including water medicinal preparation has mellowly carried on the comparison.

摘要在催化剂、阻聚剂、带水剂存在的条件下，由甲基丙烯酸与聚乙二醇单甲醚(400)直接酯化合成甲基丙烯酸聚乙二醇单甲醚(400)酯，并对酸醇比、催化剂、阻聚剂、带水剂等影响因素进行了比较。

The objective of this article was to review the production of methyl mercaptan and the relationship of methyl mercaptan and periodontitis.

本文就甲基硫醇的生成机制及其对牙周组织的破坏机制进行综述。

The analytical method for sodium methyl mercaptide was established based on the reaction in quantity between methyl mercaptan and iodine at the base condition.

采用甲硫醇与碘在碱性条件下定量反应生成双硫醚的反应原理，建立了甲硫醇钠的定量分析方法。

In this paper, the processes of methyl acetate recycling were reviewed; the method of separation methyl acetate-methanol by salt effect distillation was proposed.

本文对现行醋酸甲酯的几种回收工艺进行了评述，提出了加盐萃取精馏分离醋酸甲酯-甲醇的方法。

It is a classical chemical process for production of methyl acetate. But by the limits of. the formation of azeotropes in the process,we can't obtain hign purity methyl acetate by normal unit operation.

醋酸甲酯的制备是一种经典的化学过程，但由于反应过程中形成共沸物的限制，通过常规的单元操作不能够得到高纯度的醋酸甲酯。

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。

It is a classical chemical process for production of methyl acetate. But by the limits of. the formation of azeotropes in the process, we cant obtain hign purity methyl acetate by normal unit operation.

醋酸甲酯的制备是一种经典的化学过程，但由于反应过程中形成共沸物的限制，通过常规的单元操作不能够得到高纯度的醋酸甲酯。

Now, however, all children continue in "comprehensive" schools, and the eleven-plus determines which courses of study the child will follow.

然而现在，所有的孩子都要在综合学校继续学习，所以这次考试只是决定他们将要学习哪些课程。

Cultivatable land , and led to a general recognition that development must not be carried at the cost of agriculture .

城区的迅速扩大在很多情况下侵占了宝贵的可耕地，使人们普遍认识到发展不能以牺牲农业为代价。