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针对液体酸存在的设备腐蚀及回收利用问题,利用质子酸酸化的1-乙基-3-甲基咪唑四氟硼酸([emim]BF4)离子液体(ILs)既作反应溶剂又作催化剂,催化苯氨基甲酸甲酯(MPC)与甲醛缩合制备4,4’-二苯甲烷二氨基甲酸甲酯(4,4’-MDC)反应。考察了反应温度、原料配比、离子液体用量及反应时间等因素对4,4’-MDC合成反应的影响。适宜的反应条件为:70℃、n(MPC)/n(HCHO)=4/1、wt(ILs)/wt(MPC)=4/1、1.5h,此时4,4’-MDC产率为71.7%、选择性为71.9%。借助超声波对反应后的酸化离子液体进行萃取提纯,处理后的酸化离子液体循环使用时其催化活性基本保持不变。 相似文献
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酸性离子液体[HSO3-bpy]CF3SO3催化合成MDC 总被引:2,自引:0,他引:2
制备了一系列磺酸吡啶功能化酸性离子液体(ILs),采用Hammett指示剂与紫外联用法测定了其酸强度。考察了各酸性离子液体在苯氨基甲酸甲酯(MPC)与甲醛缩合制备二苯甲烷二氨基甲酸甲酯(MDC)反应中的催化活性。结果表明,离子液体的酸强度与其催化活性关联较好;[HSO3-bpy]CF3SO3酸强度最高,催化活性也最好。以[HSO3-bpy]CF3SO3为催化剂兼溶剂,优化了MDC合成反应条件。在反应温度70℃,反应时间60min,MPC与甲醛的摩尔比为12,离子液体与MPC的质量比为4的条件下,MDC产率最高可达91·5%。用水处理反应液,通过减压蒸馏后的离子液体可以循环使用5次以上。 相似文献
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制备了一系列磺酸吡啶功能化酸性离子液体(ILs),采用Hammett指示剂与紫外联用法测定了其酸强度。考察了各酸性离子液体在苯氨基甲酸甲酯(MPC)与甲醛缩合制备二苯甲烷二氨基甲酸甲酯(MDC)反应中的催化活性。结果表明,离子液体的酸强度与其催化活性关联较好;[HSO3-bpy]CF3SO3酸强度最高,催化活性也最好。以[HSO3-bpy]CF3SO3为催化剂兼溶剂,优化了MDC合成反应条件。在反应温度70℃,反应时间60 min,MPC与甲醛的摩尔比为12,离子液体与MPC的质量比为4的条件下,MDC产率最高可达91.5%。用水处理反应液,通过减压蒸馏后的离子液体可以循环使用5次以上。 相似文献
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盐酸盐助剂对硫酸催化合成二苯甲烷二氨基甲酸甲酯的影响 总被引:1,自引:0,他引:1
二苯甲烷二氨基甲酸甲酯(MDC)是非光气法合成二苯甲烷二异氰酸酯(MDI)的中间体。以硫酸为催化剂,盐酸盐为助剂,研究了苯氨基甲酸甲酯(MPC)与甲醛缩合制备MDC的反应。对助剂盐酸盐进行了筛选,发现氯化铜的效果较好,其MPC转化率达96%,4,4′-MDC产率可达76.7%。反应条件为:m(硫酸)∶m(MPC)=4∶1,n(MPC)∶n(HCHO)=1∶1,氯化铜用量为MPC物质的量的5.4%,100 ℃下反应3 h。将氯化铜分别与氯化镧和氯化亚铈以物质的量的比1∶1复合使用,发现单独使用氯化铜的效果好于复合盐酸盐的效果。分别使用甲醛溶液、三聚甲醛和多聚甲醛为亚甲基化剂,发现价廉易得的甲醛溶液效果最好。 相似文献
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用碳酸二甲酯(DMC)代替光气,与苯胺甲氧羰基化反应制得苯氨基甲酸甲酯(MPC),在盐酸催化剂的作用下,经甲基化缩合反应合成了4,4-二苯甲烷二氨基甲酸甲酯(MDC);使用液-质联用仪分析了反应物组成;测定了MDC的熔点;采用核磁共振仪对产品结构进行了表征;考察了反应温度、物料配比、反应时间、催化剂用量对MDC收率的影响。实验结果表明,在n(MPC/甲醛)=6:1、15%盐酸用量15mL、反应温度90℃、反应时间3h的条件下,MDC收率达到63%。该合成方法具有便于光气法改造、反应条件温和、催化剂易得易分离等优点。 相似文献
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综述了国内外以苯氨基甲酸甲酯(MPC)为原料合成二苯甲烷二氨基甲酸甲酯(MDC)的研究情况,分别对比了催化剂、物料配比、反应温度、反应时间、催化剂量等反应条件的优化结果,并就不同种类的催化剂进行了总结比较,包括液体酸(盐酸、硫酸、混合酸等)、固体酸(硅钨酸、磷钼酸等)等催化剂,以及新型催化剂如离子液体、离子交换树脂等。介绍了在反应溶剂和工艺路线方面最新的研究进展,总结了未来缩合合成MDC在催化剂上的研究方向及前景。 相似文献
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研究了4,4′-二氨基二苯甲烷(MDA)与碳酸二甲酯(DMC)甲氧基羰基化合成4,4′-二苯甲烷二氨基甲酸甲酯(MDC)的反应,研究了反应的影响因素,并采用FTIR、1 H NMR等测试方法对合成产物的结构进行了表征。结果表明,合成MDC的最佳反应工艺为反应温度160℃,用醋酸铅催化,且m(醋酸铅)∶m(MDA)=6%,反应物配比n(DMC)∶n(MDA)=20∶1,反应时间3h。在上述反应条件下,MDA的转化率达到100%,MDC的收率达到96.6%。 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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D. G. Gordeev L. F. Gudarenko M. V. Zhernokletov V. G. Kudel’kin M. A. Mochalov 《Combustion, Explosion, and Shock Waves》2008,44(2):177-189
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation
of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from
the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008. 相似文献
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Jorge Marcelo Romero Soledad Bustillo Hugo Enrique Ramirez Maisuls Nelly Lidia Jorge Manuel Eduardo Gómez Vara Eduardo Alberto Castro Alicia H. Jubert 《International journal of molecular sciences》2007,8(7):688-694
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out. 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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醋酸纤维素取代基分布与性质的关系 总被引:9,自引:0,他引:9
分析了以吡啶为溶剂的醋酸纤维素的13C-NMR核磁共振谱,得出了三种不同位置羟基的取代度。结合X—射线和DSC分析,初步说明具有相同取代度但未经水解和经过水解的醋酸纤维素(CA) 性质上的差异是由于三个羟基上的取代度分布不同及消晶程度差异所致。 相似文献
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1 INTRODUCTIONBecause of importance of equations of state (EOS)in science and industry,hundreds forms of EOS havebeen presented since latter 19th century.It seems impossible to develop a general equation covering vari-ous kinds of EOS.But for cubic EOS,several generalequations have been reported already. Martin presented the first general equation whichis following p=RT/V-α(T)/(υ β)(υ γ) δ(T)/υ(υ β)(υ γ) (1) Kumar et a1.presented an equation called the most general form of a density-cubic or, alterna tively,volume-cubic mathematical equation,the form of which is as follows 相似文献
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