分子筛催化异丁烷与正丁烯烷基化反应性能

以Y、β、MCM-41和EU-1分子筛为活性组分制备异丁烷与正丁烯烷基化反应催化剂,并利用NH_3-TPD和N_2物理吸附-脱附对催化剂进行表征。结果表明,HY分子筛催化剂的总酸量最大,MCM-41分子筛催化剂的总酸量最小,Hβ和HEU-1分子筛催化剂总酸量适中,Hβ分子筛催化剂平均孔径最大,而大孔径有利于分子扩散。对分子筛催化异丁烷与正丁烯反应的催化性能进行研究,结果表明,Hβ分子筛催化剂的失活速率最低,正丁烯异构化率最低,生成的烷基化油辛烷值达85.2,对Hβ分子筛催化剂进行Pt元素改性后催化剂的失活速率降低。     

异丁烷与丁烯烷基化反应用新分了筛催化剂的研究

探讨了六方沸石分子筛催化剂对异丁烷与丁烯烷基化反应的催化活性,。实验确定了烷基化反就的工,以应时间,异丁烷与丁烯尔比及反应压力对丁烯转化率及目的产物Ｃ＾０８的选择性的影响。     

异丁烷/丁烯烷基化固体酸催化剂的再生方法研究进展

阐述了固体酸烷基化催化剂在异丁烷/丁烯烷基化中的再生方法研究进展,包括金属临氢再生、氧化煅烧再生、超临界流体再生、洗涤再生,同时对固体酸烷基化催化剂的失活原因和失活形式进行了分析评述。这些方法在一定条件下可以实现催化剂不同程度的再生,但由于操作以及成本等原因都停留在实验室阶段,本文综合比较了各种再生方法的再生工艺过程以及再生效果,分析各种再生方法的优劣。固体酸烷基化催化剂失活较快是阻碍异丁烷/丁烯固体酸烷基化工艺工业化的关键因素,研究探索操作简单、成本低、有效的固体酸烷基化催化剂再生方法仍将是今后该领域的研究热点。     

分子筛酸性对异丁烷/丁烯烷基化反应性能的影响研究进展

概述分子筛的酸性特点,介绍固体酸催化的异丁烷/丁烯烷基化反应机理,并对已用于异丁烷/丁烯烷基化反应的分子筛情况进行总结,重点阐述分子筛的酸性对烷基化反应性能的影响。结果表明,分子筛应有合适的酸强度,综合来看,中强B酸更有利于反应。今后的机理研究中应当关注L酸及酸位空间分布对烷基化反应的影响。     

离子液体催化异丁烷与丁烯烷基化反应的研究

以三氯化铝、吡啶和HCl为基本原料,合成出一种离子液体,并在高压釜中考察了这种离子液体对异丁烷与丁烯烷基化反应的催化效果以及相关反应条什的影响.实验结果表明,所合成的离子液体对异丁烷与丁烯的烷基化反应具有较好的催化性能,在催化反应过程中,离子液体可重复使用,稳定性较好;失活后的离子液体可以用AlCl3进行再生:而且,离子液体与烷基化产物很容易分离.     

用于异丁烷-丁烯-1烷基化反应的离子液体催化剂

研究了离子液体对异丁烷与正丁烯烷基化反应的催化作用,考察了离子液体组成、异丁烷与正丁烯物质的量比等因素对烷基化反应的影响.结果表明:AlCl3质量分数为0.65～0.70的离子液体是很好的烷基化催化剂,离子液体中AlCl3的含量过低,有利于烯烃聚合,过高则有利于深度烷基化反应;在反应温度为10～25 ℃,异丁烷、正丁烯在质量比大于2.5的条件下反应,正丁烯的转化率可达到100%的.     

离子液体催化异丁烷/丁烯烷基化反应的研究进展

简要介绍了用于异丁烷/丁烯烷基化反应的传统烷基化催化剂和固体酸催化剂的优缺点。阐述了离子液体的性质及其催化异丁烷/丁烯烷基化反应的可能。综述了用于异丁烷/丁烯烷基化反应的氯铝酸离子液体,包括常规氯铝酸离子液体催化剂、改性的氯铝酸离子液体催化剂和复合离子液体催化剂。同时指出了这些催化剂存在的问题。着重强调了非氯铝酸离子液体在催化异丁烷/丁烯烷基化反应中的优势特点及其最新研究进展。     

异丁烷与丁烯烷基化反应用新分子筛催化剂的研究

探讨了六方沸石分子筛催化剂对异丁烷与丁烯烷基化反应的催化活性。实验确定了烷基化反应的温度、反应时间、异丁烷与丁烯摩尔比及反应压力对丁烯转化率及目的产物Ｃ０８ 的选择性的影响。并对各种参数的影响进行了简要分析。在适宜反应条件下,丁烯的转化率达到９８％ ,对Ｃ０８ 的选择性接近９３ ％ 。还进行了催化剂的物性测定,利用红外光谱和ＴＰＤ 氨脱附表征了催化剂表面酸中心性质及酸强度。测定结果表明,该催化剂具有大的比表面积,较多的酸中心和较高的酸强度,因而对异丁烷与丁烯的烷基化具有较高的催化活性。     

固体酸催化剂在异丁烷／丁烯烷基化反应中的应用

概述了沸石催化剂、固体超强酸催化剂等在异丁烷／丁烯烷基化反应中地研究进展及其应用效益。     

分子筛催化异丁烷/丁烯烷基化反应的失活行为及对策分析

分子筛在催化异丁烷/丁烯烷基化反应过程中表现出良好的催化活性和择形选择性,但反应过程易生焦,导致催化剂寿命较短。本文对分子筛的宏观失活过程、焦组分的定性表征分析和失活分子筛的处理对策进行了综述,发现目前对焦组分的定性和定量分析并不全面,而现有的结论多是基于实验现象的宏观推测,导致分子筛的失活机理研究并不明确;在失活处理对策方面,再生后的分子筛活性不理想且工艺复杂、投资较大。本文在总结焦组分的结构特征基础上,以焦组分模型化合物为导向,对其生焦路径进行了推导,为从动力学角度进行焦组分的定量研究提供了可能性。另外多角度分析了分子筛生焦失活原因,并提出微观层面界定焦组分对分子筛性能影响的差异性是进一步研究烷基化反应分子筛失活机理的方向。     

稀土La改性X分子筛催化异丁烷/丁烯烷基化反应

采用液相离子交换法,通过改变交换和焙烧次数制备了5种不同浓度稀土La改性的X分子筛催化剂,使用连续进料的固定床反应器评价其催化异丁烷/丁烯烷基化反应的性能,分析了分子筛物相结构的变化,考察了分子筛的酸性. 结果表明,催化剂制备过程对催化剂结构和性能影响显著,La3+改性后X分子筛结晶度下降,但酸度显著增强,随La3+交换次数增加,分子筛的B酸量增多,L酸量减少;5种催化剂中,焙烧前离子交换2次、焙烧后再交换3次、再焙烧所制催化剂催化性能最佳,丁烯的初始转化率为89.94%, C8收率可达66.71%,这归因于酸性增加加快了氢负离子转移,降低了碳正离子上发生重复烷基化的可能性,抑制了大分子生成. 反应温度和烯烃空速对反应影响显著,温度从80℃升至100℃,副反应裂解生成的C5?C7从9.64%增加到36.74%;丁烯进料空速从0.1 h?1降至0.05 h?1时,低聚生成的C9+从7.2%增至31%.     

Research progress in ionic liquids catalyzed isobutane/butene alkylation

The complicated reaction mechanism and the character of competitive reactions lead to a stringent requirement for the catalyst of C4 alkylation process. Due to their unique properties, ionic liquids (ILs) are thought to be new potential acid catalysts for C4 alkylation. An analysis of the regular and modified chloroaluminate ILs, novel Br?nsted ILs and composite ILs used in isobutane/butene alkylation shows that the use of either ILs or ILs coupled with mineral acid as homogeneous catalysts can help to greatly adjust the acid strength. By modifying the struc-tural parameters of the cations and anions of the ILs, the solubility of the reactants could also be adjusted, which in turn displays a positive effect on improving the activity of ILs. Immobilization of ILs is an effective way to mod-ulate the surface adsorption/desorption properties and acid strength distribution of the solid acid catalysts. Such a process has a tremendous potential to reduce the deactivation of catalyst and enhance the activity of the solid acid catalyst. The development of novel acid catalysts for C4 alkylation is a comprehensive consideration of acid strength and its distribution, interfacial properties and transport characteristics.     

Deactivation behavior of the catalyst in solid acid catalyzed alkylation: effect of pore mouth plugging

The deactivation of solid acid catalysts in liquid-phase alkylation of isobutane with butenes was investigated. The role of pore mouth plugging, in particular, was studied and it was found that it had a significant effect on the deactivation behavior. Simple explicit correlations were developed for catalyst lifetime in a CSTR, both in terms of time-on-stream and butene turnover per catalyst weight. The correlations were tested using available experimental data from the literature and a reasonable agreement was observed. It was shown that for a zeolitic catalyst the butene turnover per catalyst weight was proportional to the square root of catalyst loading, while it was inversely proportional to both the olefin feed concentration and the square root of feed flow rate.     

Modeling of catalyst deactivation in zeolite-catalyzed alkylation of isobutane with 2-butene

The deactivation of solid acid catalysts in liquid phase alkylation of isobutane with 2-butene was investigated. Since under liquid phase conditions the alkylation reaction is severely diffusion limited, effects of diffusion on the rate of reaction and deactivation pathways were considered. In the present work, an attempt has been made to implement more appropriate assumptions in order to properly model catalyst deactivation in a mixed reactor. Accordingly, spatial variation of diffusivity in the pores of the catalyst was considered as a function of time on stream. The effect of the pore mouth plugging was also investigated and it was found that this phenomenon had a pronounced effect on the deactivation behavior of the catalyst. An empirical order of deactivation was determined through a power-law expression for alkylation over a faujasite (FAU) zeolite.     

Trimerization of Butene over Ni-doped Zeolite Catalyst: Effect of Textural and Acidic Properties

The amount of acid sites on external surface and L/B ratio of the zeolite catalysts are close relative to the catalytic performance of the catalysts in butene trimerization. The doping of Ni into the zeolite modifies the textural and acidic properties of the catalyst. NiHβ(32) exhibits the highest catalytic performance and the lowest apparent activity energy in butene trimerization among the investigated catalysts, due to the reason that it has the proper amount of acid sites on external surface and the proper L/B ratio.     

丁烯烷基化固体酸催化剂的研究进展

阐述了异丁烷 丁烯烷基化催化剂的发展状况,主要涉及了几种新型固体酸催化剂,包括固体超强酸催化剂、分子筛催化剂和负载型杂多酸催化剂。文章着重对SO2-4 MxOy、MCM-41和负载型杂多酸催化剂的制备,活性和选择性作了探讨。同时指出了这些固体酸催化剂存在的问题,预测了烷基化催化剂研究的发展方向。     

丁烯齐聚酸性催化剂的研究进展

介绍了丁烯在酸性催化剂上齐聚的反应机理,并以固体磷酸催化剂、分子筛催化剂、负载型催化剂和酸性树脂催化剂为线索,评述了国内、外用于丁烯齐聚反应的酸性催化剂的研究进展。     

Catalytic cracking of 1-butene to propene and ethene on MCM-22 zeolite

Catalytic cracking of butene to propene and ethene was investigated over HMCM-22 zeolite. The performance of HMCM-22 zeolite was markedly influenced by time-on-stream (TOS) and reaction conditions. A rapid deactivation during the first 1 h reaction, followed by a quasi-plateau in activity, was observed in the process along with significant changes in product distributions, which can be attributed to the fast coking process occurring in the large supercages of MCM-22.

Properly selected reaction conditions can suppress the secondary reactions and enhance the production of propene and ethene. According to the product distribution under different butene conversion, we propose a simple reaction pathway for forming the propene, ethene and by-products from butene cracking.

HMCM-22 exhibited similar product distribution with the mostly used high silica ZSM-5 zeolite under the same conversion levels. High selectivities of propene and ethene were obtained, indicating that the 10-member ring of MCM-22 zeolite played the dominant role after 1 h of TOS. However, MCM-22 exhibited lower activity and stability than that on high silica ZSM-5 zeolite with longer time-on-stream.     

甲苯甲醇烷基化制对二甲苯催化剂中试反应性能研究

经过多步改性制备了负载二氧化硅（SiO₂）、氧化镁（MgO）、五氧化二磷（P₂O₅）、贵金属铂（Pt）的纳米ZSM-5分子筛催化剂,并在六段固定床反应器上分段装填该催化剂720 g进行甲苯、甲醇烷基化制对二甲苯反应活性评价。实验结果表明,通过调变甲醇和甲苯物质的量比可以使甲苯转化率在22%~30%可调,烷基化液相产物中二甲苯选择性保持在95%以上,二甲苯中对二甲苯选择性保持在95%以上;催化剂单程寿命达到1 300 h,随着反应时间延长催化剂的活性有所下降。通过X射线衍射（XRD）、热重分析（TG-DTG）和氮气吸附-脱附等手段对参加反应前后的催化剂进行了表征,结果表明反应中生成的积炭堵塞了分子筛的孔道或覆盖了催化剂的活性位;经过在反应器内原位再生,催化剂的反应活性基本恢复到新鲜催化剂水平。