共查询到18条相似文献,搜索用时 125 毫秒
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以三(三苯基磷)氯化铑(简称Rh)为催化剂、氯苯为溶剂,在高压釜中对丁腈橡胶(NBR)进行加氢反应,制得了氢化丁腈橡胶(HNBR),考察了Rh/NBR(质量比)、胶液质量分数、氢气压力、反应温度和反应时间对加氢度的影响.结果表明,在Rh/NBR为150×10-6~200×10-6、胶液质量分数为4% ~6%、氢气压力为... 相似文献
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氢化丁腈橡胶具有良好的耐油性和耐氧性,广泛应用于汽车和石油行业,通过丁腈橡胶溶液均相催化加氢制得,采用铑类和钯类均相催化剂。考察不同溶剂、催化剂及m(Ru)∶m(丁腈橡胶)对丁腈橡胶加氢的影响。采用红外光谱法和核磁法对氢化丁腈橡胶的结构进行分析,筛选出价廉、活性高和选择性高的催化剂。结果表明,在丁腈橡胶加氢反应中,丁酮可作为溶剂,Ru(PPh3)3Cl2催化剂具有高活性和高选择性。在丁酮200 m L、丁腈橡胶5 g、Ru(PPh3)3Cl2催化剂、m(Ru)∶m(丁腈橡胶)=0.000 20∶1、反应温度140℃、氢压8.0 MPa和反应时间4 h条件下,加氢度和选择性均达到100%,具有与Rh(PPh3)3Cl相当的催化性能。 相似文献
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采用自制钌系催化剂[1,3-双(三甲基苯基)-2-咪唑啉亚基]二氯(邻甲氧基苯亚甲基)合钌制备了氢化丁腈橡胶(HNBR)乳液,考察了催化剂的催化活性、对双键的选择性及所得HNBR的凝胶含量、硫化特性、物理机械性能、耐热空气老化和耐油性能。结果表明,该钌系催化剂可以选择性氢化丁腈橡胶分子链上的碳碳双键而保留氰基。当催化剂占丁腈橡胶的质量分数为0.05%时,反应3 h即可得到加氢度95%以上且不含凝胶的HNBR产品。在乳液状态下使用该催化剂制备的HNBR的各项性能与进口产品Therban 3406相当。 相似文献
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综述了溶液加氢法和乳液加氢法制备氢化丁腈橡胶用催化剂,以及新型烯烃复配加氢催化剂的研究进展,并提出了今后的研究方向。 相似文献
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研究了各种反应条件对贮氢合金MINi5-x(CoMnAl)x的氢化物对丁腈橡胶溶液双键加氢的影响。随着反应温度升高氢化度也提高;当舍金氢化物超过理论用量的2倍时,氢化度与催化剂的用量无关;氢化度与反应时间不是简单的线性关系;关于溶剂的影响,发现溶剂为氯仿时无加氢反应发生,而在四氢呋喃中则可得到具有较高氢化度的产物。此外还发现丁腈橡胶氢化度受反应气氛、氢压等因素的影响。 相似文献
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采用松香酸皂、油酸皂和萘磺酸钠甲醛缩合物复合乳化体系,通过热法合成丁腈橡胶NBR3604,考察了影响生胶门尼黏度及硫化胶拉伸强度和扯断伸长率等的主要因素。结果表明,合成NBR3604 较适宜的配方和工艺条件为: 丁二烯56 份( 质量) ,丙烯腈44 份,软水275 份,过硫酸钾0. 5 份,三乙醇胺0. 125 份,调节剂丁0. 45 ~ 0. 60 份,乳化剂3 ~ 4 份且松香酸皂与油酸皂质量比为4 /6 或5 /5,聚合温度( 30 ± 1) ℃,单体转化率( 70 ± 2) %。在此条件下的反应过程平稳,产品各项性能符合指标要求,重复性较好。 相似文献
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丁腈橡胶(NBR)选择性催化加氢是制备高附加值、高性能氢化丁腈橡胶(HNBR)的一个重要过程。将链段中C==C双键加氢饱和而保留氰基基团,不仅可保持其原有的耐油性和耐磨性,而且可极大地改善其耐侯性、耐臭氧性等。本文介绍了NBR加氢的几种工艺,着重综述了NBR非均相催化加氢的研究进展及发展方向,探讨了负载型催化剂的载体孔道结构和表面性质及活性组分组成对NBR加氢性能的影响。本文还对非均相催化加氢过程中的溶剂效应、催化剂的回收和循环再生进行了阐述,提出溶剂对催化加氢速率和加氢度都有重要影响,溶剂的受氢能力(β值)是影响加氢过程的关键参数。催化剂失活的主要原因是表面活性位点被聚合物覆盖,而利用有效的溶剂洗涤或者采用催化剂表面功能化的方式,可促使活性位再次暴露,恢复其加氢活性。最后,对非均相加氢制备高附加值HNBR体系中的催化剂设计、溶剂效应和催化剂再生等发展方向进行了展望。 相似文献
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The catalytic hydrogenation of acrylonitrile‐butadiene copolymer (nitrile rubber, NBR) using Pd(OAc)2 or RuCl2(PPh3)3 catalysts has been investigated in order to produce a totally saturated nitrile rubber. The hydrogenation of NBR is effective with both catalysts and achieved total conversion under the appropriate reaction conditions. In the case of palladium the effects of reaction parameters such as reaction temperature, pressure, time, catalyst concentration, and NBR concentration have been investigated. Even though both ruthenium‐ and palladium‐based catalysts are effective in the production of HNBR, the former requires harsh reaction conditions and has the drawback of gel formation under high conversion, motivating the migration to RuCl2 (PPh3)3 as an alternative catalyst. The degree of hydrogenation was determined by IR and NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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It was difficult to obtain high degree of hydrogenation of hydroxyl‐terminated liquid nitrile rubber (HTBN) by using homogeneous noble metal catalyst because the hydroxyl (? OH) in HTBN was likely to cause catalyst poisoning. In this study, with hexamethyl disilylamine protecting ? OH, a good yields of hydrogenated HTBN was synthesized through the use of homogeneous metal catalyst. The effects of catalyst concentration, reaction time, hydrogen pressure, and temperature on the hydrogenation of HTBN were investigated and obtained the following optimum process parameter values: catalyst mass fraction of 0.8%, reaction time of 8 h, pressure of 1.6 MPa, and temperature of 100°C. Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy were used to characterize the hydrogenation product of the protected HTBN, indicating that under certain conditions a high degree of hydrogenation of HTBN can be achieved. Only the carbon–carbon double bonds (C?C), not the ? CN bonds, are subject to hydrogenation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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Dynamic behavior of continuous processes was numerically investigated for the catalytic hydrogenation of nitrile butadiene rubber, based on developed models, which took into account the coupling between kinetics and mass transfer. The evolution of hydrogenation reaction trajectories in both cases were analyzed. It is proposed that the coupling behavior between the catalytic hydrogenation and mass transfer was completely determined by the ability of the catalyst in activating hydrogen, carbon‐carbon double bond loading level and the relative capacity of reaction to mass transfer as well as the residence time in the reactor. Four dimensionless parameters were derived to characterize these aspects. The effects of operation conditions on the hydrogenation processes were investigated. The application of the ideal flow models to non‐ideal flows was in addition discussed. It is suggested that the optimal reactor for such a hydrogenation system would be a plug flow reactor with an instantaneous well‐mixing component in the inlet of it, and a reasonable approach to the proposed optimal reactor should be with the flow behavior of at least three continuous stirred tank reactors in series. Further research directions are suggested. 相似文献
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对丁腈橡胶非均相催化加氢制备高附加值氢化丁腈橡胶过程中催化剂失活的原因进行了探究,发现造成催化剂活性下降的原因并不是贵金属纳米颗粒的流失、团聚或中毒,而是催化剂表面的活性位被聚合物覆盖而无法与反应物接触,因此将覆盖在活性位上的聚合物进行脱除才是催化剂再生和重复利用的关键。根据相似相容原理选择单溶剂或者混合溶剂对反应后催化剂进行处理,结果表明经过乙酸乙酯、丁酮、N,N-二甲基甲酰胺以及N-甲基吡咯烷酮这四种有机溶剂处理后,其催化加氢活性可以恢复至新鲜催化剂活性的90%;当用混合溶剂处理后,其催化活性可以提高至新鲜催化剂活性的95%,且循环利用4次其催化活性仍能保持不变。 相似文献