HY分子筛催化异丁烷与丁烯烷基化反应研究

本文对Y型分子筛进行了合成并将其应用于异丁烷与丁烯烷基化反应,考察了工艺条件对催化剂上烷基化反应性能的影响。实验结果表明,空速提高后催化剂上丁烯转化率下降,适当提高温度有利于提高HY催化剂上烷基化活性,烷烯比的提高可以有效的抑制烯烃的聚合等副反应从而有利于烷基化反应平稳进行。最后得出HY型分子筛催化剂在压力2.0MPa下,烷烯比120、低空速0.037h~(-1)、温度80℃最有利于烷基化反应的进行。     

室温离子液体催化异丁烷-丁烯烷基化的中试研究

在Et2NHCl—AlCl3离子液体催化异丁烷-丁烯烷基化实验室研究的基础上,考察了离子液体的放大合成和中试规模的离子液体烷基化反应。考察了反应温度、进料烷烯比和丁烯原料对反应的影响,确定了具体的反应条件。首次在中试装置上验证了使用室温离子液体取代传统HF与H2SO4进行异丁烷烷基化反应的可能性。     

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。     

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烷基化工艺条件

采用统计分析和回归正交实验方法,分析H2SO4,HF和离子液体烷基化工艺条件对异丁烷与丁烯的烷基化反应生成三甲基戊烷选择性的影响,并考察了离子液体烷基化循环使用性能.结果表明,由于离子液体呈Lewis酸性,在催化异丁烷和1-丁烯烷基化反应时,三甲基戊烷选择性很低.以离子液体为催化剂,在反应温度大于15℃,搅拌速率大于1 500 r/min,异丁烷与2-丁烯物质的量之比大于10,催化剂与反应物体积分别为50和150 mL的条件下进行烷基化反应,离子液体循环使用20次以上,三甲基戊烷选择性仍大于80%.通过中试烷基化实验验证反应温度、搅拌速率、烷烯比与三甲基戊烷选择性之间的多元线性回归方程,发现三甲基戊烷选择性的计算值与实验值吻合较好.表明所得的方程具有较好的预测能力.     

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。     

醚基功能化离子液体合成及催化烷基化反应

合成了一系列酸性的醚基功能化离子液体,对其进行了表征和测定。通过乙腈探针红外光谱法确定了最强酸性的催化剂,并将其用于催化异丁烷与2-丁烯的烷基化反应。结果表明:1-甲氧基乙基-3-甲基咪唑溴氯铝酸离子液体([MOEMIM]Br/AlCl₃)在AlCl₃摩尔比为0.75时酸性最强,催化烷基化反应效果最佳;在反应温度35℃,异丁烷与2-丁烯体积比10:1的反应条件下催化烷基化反应,可得到C₈选择性66.6%的烷基化油;其催化效果远优于非醚基功能化氯铝酸离子液体的催化效果;该催化剂可循环利用。     

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。     

异丁烷丁烯烷基化工艺技术应用进展

介绍了氢氟酸烷基化、硫酸烷基化、离子液体烷基化、固体酸烷基化等异丁烷丁烯烷基化技术特点以及工业应用情况。分析指出尽管硫酸烷基化工艺存在废酸处理、设备腐蚀等问题,但就安全性和易操作性而言硫酸烷基化技术仍是现阶段生产烷基化油技术路线中最好的选择。复合离子液体在异丁烷丁烯烷基化反应中显示出比硫酸和氢氟酸更高的催化活性,是另一个可供选择的生产高质量烷基化油的技术路线。异丁烷丁烯固体酸烷基化技术相比于其他液体烷基化工艺从本质上实现了安全、环保,是未来异丁烷丁烯烷基化技术的发展方向。     

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.     

Ab initio calculations on the mechanism of isobutane and 2-butene alkylation reaction catalyzed by hydrofluoric acid

Ab initio method was employed to determine the mechanism of alkylation reaction of 2-butene with isobutane. The results indicated that 2-butene is rapidly protonated to form sec-butyl carbonium ion, which then reacts with isobutane to form tert-butyl carbonium ion. The resulting carbonium ion is then deprotonated to form isobutene that reacts rapidly with tert-butyl carbonium ion to form trimethylpentane (TMP) carbonium ion. Finally, the TMP⁺ carbonium ion is converted to TMP via the hydride transfer process. The transition states of the interactions were obtained by using the SCAN method (a calculation key word for potential energy surface) first and then the intrinsic reaction coordinates were traced using the Gaussian program. In addition, the energy changes and geometric parameters of the interactions were analyzed. The computed results indicated that the energy barriers are close to or less than zero for the interaction of isobutane with protonated 2-butene or for the interaction of tert-butyl carbonium ion with isobutene, suggesting rapid reaction steps of the carbonium ions. The 2,2,3-TMP is kinetically controlled, while the formation of 2,2,4-TMP is controlled by reaction equilibrium. The calculated results were in good agreement with the experimental results.     

Nafion-H as catalyst for isobutane/2-butene alkylation compared with a cerium exchanged Y zeolite

A solid superacidic Nafion-H polymer was examined as a catalyst for isobutane/2-butene alkylation and compared with a cerium-exchanged Y zeolite. Both catalysts demonstrate initial alkylation activity with rapid decrease in alkylation selectivity. The total product distributions were found to be significantly different after three hours of reaction. Nafion-H showed less selectivity towards iso-octanes, but formed relatively more 2,2,4-trimethylpentane. The differences between the two catalysts suggest dissimilar favoured reaction mechanisms.     

Isobutane/2-butene alkylation on MCM-22 catalyst. Influence of zeolite structure and acidity on activity and selectivity

The catalytic behavior of the novel MCM-22 zeolite for the continuous alkylation of isobutane with 2-butene has been investigated at a temperature of 50°C, 2.5 MPa total pressure, and a variety of olefin space velocities. At high olefin conversions the MCM-22 zeolite showed a very high initial cracking activity attributable to strong Brønsted acid sites, as well as to the existence of strong diffusional restrictions of the TMP's (formed inside the zeolite) to exit through the channels. At short times on stream (TOS), TMP's account for ca. 40% of the C₈ fraction. The olefin conversion and the cracking activity rapidly decline with TOS, while the alkylate product became richer in dimethylhexenes, indicating a predominance of 2-butene dimerization and a loss of hydrogen transfer activity as the catalyst aged. Moreover, MCM-22 gives less TMP's than large-pore zeolites (USY, beta, mordenite), but more than the mediumpore ZSM-5 at similar 2-butene conversion. The latter catalyst was much more selective for olefin dimerization than for isobutane alkylation, presumably because formation of the bulkier TMP's was strongly impeded in its smaller pores.     

Regulation of isobutane/1-butene adsorption behaviors on the acidic ionic liquids-functionalized MCM-22 zeolite

The adsorption ratio of isobutane/1-butene on the catalyst surface is one of the most important factors for the C4 alkylation process.Regulation of isobutane/1-butene adsorption ratio on the zeolite-supported acid catalyst is a big challenge for catalyst preparation.To regulate the isobutane/1-butene adsorption ratio,four types of ionic liquid (i.e.,IL) with different alkyl chain lengths and different acid group numbers were synthesized and were subsequently immobilized onto the MCM-22 zeolite.The as-synthesized IL-immobilized MCM-22 (i.e.,MCM-22-IL) was characterized by FTIR,TGA,BET,XPS and XRD,and their adsorption capacities and adsorption molar ratios of isobutane to 1-butene (I/O) were investigated to correlate with surface features of MCM-22-IL Results showed that the immobilization of ILs led to a decrease of specific surface area and pore volume.But the surface density of acid groups was increased and the adsorption molar ratio of isobutane/1-butene (I/O) was significantly improved by the immobilization of ionic liquids.The adsorption molar ratio of I/O is substantially improved from 0.75 to above 0.9 at 300 kPa upon immobilizing ILs.Although the alkyl chain length of ILs was found to have little effect on the adsorption molar ratio of I/O,the increase of acid group numbers led to a dramatic decrease in the adsorption I/O ratio.The results illustrated that immobilizing ionic liquids is an effective way to modify the textural,chemical and morphological properties of MCM-22.Accordingly,the immobilization of ionic liquids provides a novel and a feasible way to regulate the adsorption I/O ratio on an adsorbent or a solid catalyst.     

Intensification of the Sulfuric Acid Alkylation Process with Trifluoroacetic Acid

H₂SO₄ alkylation of isobutane and butene is one of the primary commercial processes used to produce alkylates. This work presents a technology for the intensification of sulfuric acid alkylation with the addition of trifluoroacetic acid (TFA). The addition of TFA increased the solubility of isobutane in H₂SO₄, decreased its viscosity, and adjusted the acidity of H₂SO₄. With the addition of TFA, the selectivity of C8 was dramatically improved from 36.8 to 95.7%. The TFA content, stirring speed, reaction temperature, volume ratio of acid to hydrocarbon (H/C), molar ratio of isobutane to 2-butene (I/O), reaction time, and reuse of H₂SO₄/TFA were also investigated in this work. Compared with the conventional process, the new technology provided a considerably higher quality alkylation with considerably lower energy consumption. © 2018 American Institute of Chemical Engineers AIChE J, 65: 113–119, 2019     

Liquid-Phase Isobutane/Butene-Alkylation Using Promoted Lewis-Acidic IL-Catalysts

Abstract  

The effect of different promoters on activity and selectivity of Lewis-acidic chloroaluminate ionic liquid catalysts was studied for isobutane/2-butene alkylation. When tert-butyl halides are used as promoters, the active species of the alkylation reaction, which is the tert-butyl cation, is directly generated whereas upon catalysis with Br?nsted-acid supported ionic liquids, this species is indirectly provided through a hydride shift between protonated 2-butene and isobutane. Experimental results both from batch and continuously operated liquid phase alkylation reactors indicate, that tert-butyl halides are able to speed up the reaction rate significantly and shift the C₈-selectivity towards the desired high-octane trimethylpentanes (TMPs). However, secondary reactions like oligomerization and cracking could not be suppressed by the use of this additives and high deactivation rates in continuous opperation were observed. Suggestions are made, how the product composition is effected by the additive and how the promoted IL-catalyst system is deactivated with time on stream.     

磷钨酸催化混合C4合成醋酸仲丁酯

为了充分利用C4资源,以磷钨酸为催化剂,研究了混合C4(含1-丁烯、正丁烷、异丁烷)和冰醋酸合成醋酸仲丁酯的反应。考察了反应时间、反应温度、反应压力、催化剂用量、烯酸摩尔比对醋酸转化率的影响。结果表明,最佳合成工艺条件为:反应时间7h,反应温度170℃,反应压力5.3MPa,w(催化剂)=22.9%(相对于酸质量),n(1-丁烯)∶n(醋酸)=3.5∶1;在该条件下,醋酸转化率为91.4%,酯化选择性为90%。     

MCM-36 zeolites tailored with acidic ionic liquid to regulate adsorption properties of isobutane and 1-butene☆

Adsorption properties of an adsorbent or a catalyst towards adsorbates are crucial in the process of adsorption separation or catalytic reaction. Surface morphology and structure of adsorbents have a significant impact on the adsorption properties. In this study, a novel acidic ionic liquid, 1-butyl-3-(triethoxysilylpropyl)imidazolium hydrogen sulfate(i.e., [BTPIm][HSO_4]), was synthesized and subsequently grafted onto the MCM-36 zeolite for the regulation of its adsorption properties towards isobutane and 1-butene. The resultant [BTPIm][HSO_4]-immobilized MCM-36(i.e., MCM-36-IL) was characterized by FT-IR, XPS, XRD, SEM, TG/DTG and N_2 adsorption–desorption measurement. It was found that the specific surface area, micropore volume and mesopore volume of the MCM-36 support underwent a reduction upon the immobilization of ionic liquid,while the surface density of acid increased from 0.0014 to 0.0035 mmol·m~(-2). The adsorption capacity of isobutane and 1-butene on the MCM-36-IL was determined by a static volumetric method. Results demonstrated that the interaction between isobutane and MCM-36-IL was enhanced and the interaction between 1-butene and MCM-36-IL was reduced. As a result, a tunable adsorption ratio of isobutane/1-butene on MCM-36 was achieved.With the increase in surface density of acid and the tunable adsorption ratio of isobutane and 1-butene on the functionalized MCM-36, the acidic ionic liquid-immobilized zeolites are beneficial to obtain an improved reaction yield and a prolonged catalyst life in the reactions catalyzed by solid acid.