查询词典 acetic anhydride

Synthesis process of 2,6-dichloro-3-methylaniline was investigated 3-methylaniline was first N-acetylated with acetic anhydride,then treated with chlorosulphonic acid and ammonia yielding the 2-methyl-4--benzenesulfonic amide,which wasin turn deacetylated,chlorinated and hydrolyzed to the title compound.Hydrochloric acid was used instead of sodium hydroxide in deacetylation and sodium chlorate instead of hydrogen peroxide as oxidant in chlorination.

合成工艺2，6-二氯-3-甲基苯胺调查3-甲基首次N-乙酰与醋酸酐，然后与氯磺酸和氨产量 2-甲基-4--苯磺酰胺基，而擅转乙酰，氯化和水解的标题compound.hydrochloric酸代替氢氧化钠乙酰氯酸钠代替双氧水为氧化剂，加氯。

The volume ratio of furaldehyde to acetic anhydride is 1∶2; the mole ratio of furaldehyde with anhydrous potassium carbonate is 1.00∶0.54. The best phase transfer catalyst is PEG1000, the mass ratio of PEG1000 with furaldehyde is 4.3%, the reaction time is 11 min, the reaction power of microwave is 260 W. The yield ofα-furanacrylicacid is up to 72.3% under these reaction conditions.

研究结果表明：在微波辐射功率为260 W、微波反应时间为11 min、以聚乙二醇1 000(PEG1000)为相转移催化剂，糠醛与乙酐的体积比为1∶2，糠醛与无水碳酸钾的量比为1.00∶0.55时，α-呋喃丙烯酸的产率为72.3%。

Then the protected D-mannitol, mixed with lead tetraacetate, hippuric and acetic anhydride, were refluxed in THF for 18 h in a one-pot two step reaction to afford a chiral precursor-2-phenyl-4-[-2,3-O-]-propylidene-5(4H)-oxazolones.

产物与四乙酸铅、马尿酸、乙酐于THF中回流18 h完成一釜二步反应，纯化后得到含有手性碳原子的环丙烷氨基酸前体-2 苯基-4-[-2，3-O-]丙叉？

The invention relates to a synthesis method of N-acetylaminoglucose, which comprises dissolving D-glucosamine hydrochlorate and alcohol at the mass ratio of 2-2.5:100, adjusting the pH value of the solution to 9-10, filtering, taking the filter liquor, mixing and adding acetic anhydride at the 50-60wt% amount of D-glucosamine hydrochlorate, mixing and reacting for 2h, using absolute ethyl alcohol to recrystallizing, filtering and recrystallizing via water, to obtain rod-shape food grade N-acetylaminoglucose.

本发明涉及一种N-乙酰氨基葡萄糖的合成方法。该方法的具体步骤为：将D-葡萄糖胺盐酸盐和乙醇按2～2.5∶100的质量比溶于水中，调节该溶液的pH值为9～10；过滤，取滤液，搅拌下加入乙酸酐，其加入量为原料D-葡萄糖胺盐酸盐量的50～60wt％；搅拌反应2小时后，用无水乙醇进行重结晶；过滤，晶体再用水重结晶，得棒状食品级N-乙酰氨基葡萄糖。

In 1903, D. Vorlander and co-workers found that treatment of dibenzylideneacetone with concentrated sulfuric acid and acetic anhydride followed by hydrolysis by sodium hydroxide yielded a cyclic ketol, the structure of which was unknown at the time.

1903年，D。 Vorlander和合作者发现，二苄基丙酮与浓硫酸及醋酸酐经过氢氧化钠水解后产生了当时还不知结构的环状酮醇。

Triethyl orthoformate, industry 97 37%; diethyl malonate, industry 98%; acetic anhydride, reagent 97%.

原甲酸三乙酯，工业97 37%；丙二酸二乙酯，工业98%；醋酸酐，试剂97%。

The optimum reaction conditions were: at present of acetic anhydride, a stoichiometric quantity of nitric acid, at room temperature for 40 minutes. Nitration of chlorobenzene gave a,50% yield of mononitro compounds, and an ortho-para isomer ratio 0.20 in product distribution of chlorobenzene mononitration.

结果表明：硅钨酸催化性能较好，催化剂载体以纳米二氧化硅最好，反应条件中醋酸酐用量是主要影响因素；SiW_(12)O_(40)~(4-)／纳米SiO_2催化剂具有强对位选择性：在醋酸酐存在下，氯苯与等当量的硝酸室温下反应40分钟，氯苯一硝化产物中邻／对硝基氯苯异构体的质量比达0.2，产率可达50％。

The nitration of toluene was carried out in the presence of acetic anhydride with CCl4 as solvent, 95% nitric acid as nitrating reagent, and niobic acid calcinated at 300℃ for 3 h as catalyst for 60 min at 40℃.

实验结果表明，当反应温度为40℃，反应时间为60min时，以CCl4为溶剂，以质量分数为95%的硝酸为硝化剂，在醋酐存在条件下，以经300℃焙烧3h后的铌酸作为催化剂，甲苯硝化产物中异构体的邻对比达1.26，较硝硫混酸的1.67显著降低，产物得率达99.3%。

The effects of all kinds of factors, just like calcination temperature of niobic acid catalysts, nitration reaction time, nitration reaction temperature, recovered catalyst, acetic anhydride and concentration of nitric acid were studied by gas chromatography.

研究了催化剂焙烧温度、硝化反应时间、硝化反应温度、有无醋酸存在、硝酸浓度、催化剂的重复使用等因素对甲苯硝化反应影响。

Deoxybenzoin(3) was prepareded by using the resorcinol and substituted phenylacetic as starting meterials in microwave-mediated.Then the compound(3) was reacted with acetic anhydride to produce(4).The compound(4) was hydrolyzed to convert compound(5) in the acid-mediated. The compound(5) was reacted with the 1,2-dibromo-ethane and 1,3-dibromo-propane in refluxed condition with acetone as solvent to give(6) or(7),respectively.Lastly,the title compounds were synthesized by refluxing(6) or(7) with 2-methyl-benzimidazole and potassium carbonate in acetone solution.

以取代苯乙酸和间苯二酚为起始原料，用微波辐射法合成脱氧安息香(3)，(3)与乙酸酐缩合生成2-甲基-7-乙酰氧基异黄酮(4)，(4)在酸性条件下水解生成相应的异黄酮(5)，化合物(5)分别与1，2-二溴乙烷和1，3-二溴丙烷反应生成(6)和(7)，化合物(6)和(7)再分别与2-甲基苯并咪唑偶合生成目标化合物。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。