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氯化制备一氯乙酸的过程中,除少量未反应的醋酸外,约有3~10%二氯乙酸和1%三氯乙酸生成。为了得到较纯的一氯乙酸产品,通常用结晶法提纯,然而得到的晶体氯乙酸含量往往偏低,不能满足某些精细化工品的生产需要。近年来国外提出了几种提纯方法。1.加氢脱卤法英国专利报道,氯化液中的副产物多氯代乙酸在一定温度下与氢气作用,可以被氢化成一氯乙酸,从而提高产品质量和收率。例如含一氯乙酸94.4%、二氯乙酸4.5%、三氯乙酸0.1%及醋酸1.0%的混合物,于120 相似文献
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乙酸光氯化反应制备氯乙酸工艺的研究 总被引:5,自引:0,他引:5
设计了一种新型实验室氯化反应器--光照内环流气液反应器,应用于乙酸光氯化制氯乙酸的反应。该反应器具有光照效果好、易环流、密封性能好等。大环流反应器中考察了光照下不同反应温度对乙酸氯反应的影响,实测了不同温度下,乙酸、氯乙酸和二氯乙酸的浓度随反应时间的变化关系。将乙酸在环流反应器中的光氯伦反应结果与乙酐为催化剂的氯化反应结果进行了比较,发现光氯反应速率与乙酐为催化剂时的氯化速度时相当,但二氯乙酸生成量明显偏高,为了抑制二氯乙酸的生成,在光照的同时加入乙酐作为抑制剂,考察了不同的乙酐用量和加入方式对二氯乙酸生成的影响。 相似文献
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国内氧乙酸生产主要采用醋酸催化氨化法,氯化过程的反应(1)为主反应,(2)、(3)为副反应。从氯化反应的动力学和热力学来讨论反应物浓度和反应温度对主、副反应的影响,从而通过浓度和温度控制使主反应转化率高,副反应得到抑制。1氯化反应的浓度效应和氨化过程的控制随着反应时间的推移,反应物醋酸的浓度逐渐下降,目标产物氯乙酸的浓度开始时升高,到最大值后反而下降,与此同时副产物二氯乙酸等的浓度开始显示并逐渐增大.在氯乙酸转化最高时副产物最少,这便是氯化反应的最佳控制点。依此在氯化过程中以测定反应料液密度来分段控… 相似文献
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1原有制备方法
1.1以氯乙酸为原料
(1)在催化剂存在下用氯氯化氯乙酸,反应产物中含氯乙酰氯85%~95%,副产物为二氯乙酰氯和二氯乙酸.此方法的优点是成本低,缺点是用普通分离方法得不到高纯度的产品.
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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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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
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Conclusions It is significant that the purification on a single passage of viscose through porous ceramic corresponds to the result of a two-stage filtration of it in industrial filter-presses with standard fillings.Kiev Combine. Kiev Technological Institute of Light Industry. Translated from Khimicheskie Volokna, No. 3, pp. 20–22, May–June, 1969. 相似文献
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利用组件技术开发化工原理实验课件,给出了系统层、组件库层和应用层的架构划分。重点讨论了组件库的设计,给出了流体阻力这一典型实验的实现描述。实践证实,基于组件技术可以提高仿真实验的开发效率。 相似文献