共查询到20条相似文献,搜索用时 125 毫秒
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溴乙酸环己酯是一种重要的精细化工产品 ,主要用作农药、医药产品的中间体。通常的合成方法是先用乙酸在吡啶下和溴水反应、经分离得溴乙酸 ,然后与环己醇在硫酸作用下进行酯化反应得溴乙酸环己酯。溴乙酸也可以用氯乙酸与溴化氢反应得到 ,再进行酯化反应得溴乙酸环己酯。上述两种合成方法用于工业规模进行生产时 ,成本高、收率低、反应时间长、设备腐蚀严重。本文采用氯乙酸、溴化钠、硫酸和环己醇为原料 ,用甲苯作为恒沸剂在一个反应釜内进行反应 ,中间物溴乙酸不作分离 ,溴化和酯化反应同时进行 ,直接合成溴乙酸环己酯。反应过程为 :Na … 相似文献
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固体超强酸SO2-4/TiO2催化合成乙酸环己酯 总被引:3,自引:0,他引:3
以乙酸和环己醇为原料,用不同晶型纳米TiO2制备的SO4^2-/TiO2超强酸为催化剂合成乙酸环己酯。考察了不同晶型纳米TiO2制备超强酸催化活性、催化剂活化温度、催化剂的用量、反应物摩尔比等因素对收率的影响。实验结果表明,较适宜条件为:锐钛型纳米TiO2制备超强酸,环己醇的用量在0.4mol的情况下,催化剂活化温度450℃、催化剂的用量1.50g,环己醇与乙酸的摩尔比1:2,酯收率达95.6%。 相似文献
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氨基磺酸催化合成乙酸环己酯 总被引:15,自引:0,他引:15
研究了以氨基磺酸为催化剂 ,以乙酸和环己醇为原料合成乙酸环己酯的方法 ,讨论了影响酯化反应的各种因素 ,并得出了酯化反应的最佳工艺条件 :醇酸比为 1∶2 (0 .4mol∶0 .8mol)、1.9g氨基磺酸为催化剂、15ml环己烷为带水剂 ,反应时间 110min ,酯收率达 84 5 %。并与十二水合硫酸铁铵、氯化铁等催化剂作了比较。实验结果表明 :以氨基磺酸为催化剂具有催化剂用量少、重复使用效果好 ,反应时间短 ,酯收率高 ,方法简单等优点。 相似文献
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六水合三氯化铝催化合成乙酸环己酯 总被引:1,自引:0,他引:1
以乙酸和环己醇为原料,六水合三氯化铝为催化剂催化合成了乙酸环己酯。在优化反应条件下,酯收率达78.8%。优化反应条件如下:n(乙酸)=200 mmol,n(乙酸)∶n(环己醇)=1.0∶1.5,催化剂用量为1.5 g,带水剂环己烷用量为10 mL,反应温度为106~124℃。实验结果表明催化剂催化性能高,反应条件温和,方法简单,收率优良。 相似文献
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十二水合硫酸铁铵催化合成乙酸环己酯 总被引:29,自引:1,他引:28
以乙酸和环己醇为原料 ,十二水合硫酸铁铵为催化剂催化合成了乙酸环己酯。在优化反应条件下 ,酯收率达 80 .0 %。优化反应条件如下 :醇酸摩尔比为 1 .0∶2 .0 ,催化剂用量为 1 .5~ 2 .5 g,反应温度为 1 0 2~ 1 38°C。实验结果表明催化剂催化性能高 ,反应条件温和 ,方法简单 ,收率优良 相似文献
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氯化亚锡催化合成肉桂酸环己酯的研究 总被引:1,自引:0,他引:1
研究了用氯化亚锡作为催化剂,使肉桂酸与环己醇发生酯化反应合成肉桂酸环己酯。获得最佳反应条件为:环己醇与肉桂酸的物质的量比为3∶1,反应2.5 h,催化剂0.1 g/0.02 mol酸,收率可达93.6%。 相似文献
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乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。 相似文献
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The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure. 相似文献
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以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。 相似文献
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我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉 相似文献
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The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003 相似文献