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1.
离子液体(C2H53NHCl-xFeCl3(FeCl3摩尔分率x≥0.55)对异丁烯齐聚反应具有良好的催化性能。在反应温度40℃,反应时间30 min,酸烃比为1.2∶1的条件下,异丁烯齐聚转化率达到85%,液相产物中二聚物和三聚物的含量之和达到80%以上。在离子液体中引入适量CuCl可以提高异丁烯的转化率。当CuCl/[(C2H53NH]Cl-0.6FeCl3的摩尔比为0.25时,异丁烯的转化率达到98%,液相产物中二聚物和三聚物的含量之和高达90.20%。  相似文献   

2.
环己烯、正己烯、正辛烯等C6~C8烯烃是重要的化工原料,用途广泛。综述了环己烯及正己烯,正辛烯等C6~C8烯烃水合催化剂的研究进展。环己烯水合法制备环己醇是一种绿色制备工艺,其催化剂由最初的硫酸、磺酸等均相催化剂逐渐向分子筛等非均相催化剂过渡,其中HZSM-5分子筛以其高选择性、高活性成为工艺上常用的催化剂。环己烯间接水合法合成环己醇的途径具有高选择性,高转化率,低能耗的优点,其催化剂的研究也处在一个高速发展阶段。正己烯、正辛烯水合催化剂的研究较少。未来离子液体等新型水合催化剂将会成为环己烯水合制备环己醇的研究重点。  相似文献   

3.
从分子筛酸性组元方面综述了国内外C8芳烃异构化催化剂的研究进展,并对C8芳烃异构化催化剂酸性组元沸石分子筛的发展提出了建议。认为C8芳烃异构化催化剂的研究方向应集中在新型分子筛的制备和改性研究上。  相似文献   

4.
采用不同浓度碱液处理制备了具有不同酸性质的多级孔HZSM-5分子筛,并考察其酸性能与孔结构变化对催化裂化(FCC)汽油中C5烯烃催化裂解性能的影响。利用X射线衍射(XRD)、N2吸附脱附、氨气程序升温脱附技术(NH3-TPD)、吡啶红外(Py-IR)和扫描电镜(SEM)等表征手段研究了HZSM-5分子筛的结构、形貌、酸性质和孔道性能。研究结果表明,适宜浓度的碱液处理可以提高HZSM-5分子筛的强Br?nsted (B酸)酸量和介孔体积,显著提高C5烯烃转化率和乙烯、丙烯的收率。当碱液浓度为0.2 mol·L-1,HZSM-5分子筛强B酸中心和介孔体积之间的协同作用促进了C5烯烃的高效转化,转化率为84.8%(质量分数),乙丙烯总收率为86.0%(质量分数),分别比未处理的HZSM-5分子筛增加4.4%和15.5%。  相似文献   

5.
催化剂在混酚烷基化中的应用   总被引:1,自引:0,他引:1  
将酚铝、H2SO4和酸性阳离子交换树脂三种常见酚类催化剂分别添加到异丁烯与混(间、对)甲酚(以下简称混酚)反应实验中,比较三者催化效果。实验结果表明:在反应2.5h时,以H2SO4和酸性阳离子交换树脂为催化剂,混酚的转化率均达90%以上,而以酚铝为催化剂混酚无如此高的转化率,表明H2SO4和酸性阳离子交换树脂的催化活性强于酚铝。  相似文献   

6.
CO2加氢经甲醇(含氧中间体)制低碳烯烃工艺路线,可实现成醇、脱水两步反应串联协同进行,打破费托合成产物Anderson-Schulz-Flory(ASF)分布限制,高选择性地制取低碳烯烃。传统甲醇合成Cu基催化剂加氢能力较强,在两步反应中产物以CH4、低碳烷烃为主。实验设计、制备了CuZnTiO2/(Zn-)SAPO-34复合催化剂,实现了CO2加氢在Cu基复合催化剂上高选择性合成C2~C4烯烃(约60%)。研究表明,两步反应过程中甲醇体积分数较低(<6%),且高温下逆水煤气变换反应严重,导致催化剂酸性变化对产物分布的影响较大。调变两类活性位点比例发现,CH4的产生与串联反应存在竞争关系,SAPO-34酸量的增加抑制了CH4的生成,促进串联反应正向进行;合适的酸性有助于生成C2~C4烯烃。控制成醇、脱水两类活性位点接触距离可调变烯烃的二次反应,降低加氢能力,改善产物分布。  相似文献   

7.
C4烯烃在化工产品及医药生产领域具有非常广泛的运用,乙醇是生产制备C4烯烃的原料,在制备过程中,催化剂组合与温度对C4烯烃的选择性和C4烯烃收率将产生影响。本文就Co/SiO2和HAP装料比、每分钟乙醇注入量以及温度对C4烯烃收率产生影响三种主要因素进行了不同的组合,利用Spearman秩相关分析法研究了不同装料方式下的影响因子与C4烯烃收率的依赖级别,分别以乙醇流量和C4烯烃选择性为因变量,催化剂种类和温度为自变量建立了基于最小二乘法的多元线性回归模型,并利用鲨鱼优化算法在可行域内求得C4烯烃收率的最优值为4 994.349 862‰。  相似文献   

8.
曹飘  郑伟中  孙伟振  赵玲 《化工学报》2018,69(11):4832-4839
利用分子动力学(MD)模拟研究了不同支链长度以及官能团的Brønsted酸性离子液体(BILs)对H2SO4/C4烷烯界面特性的调控。结果表明,BILs的加入可以明显增强C4烷烯在两相界面处的溶解和扩散,有利于烷基化油品的提升。烷基链较长的阳离子表现出较强的界面密度富集现象,并且其支链倾向于伸入C4烷烯相,有利于界面性质的增强。阳离子支链的增长能够促进C4烷烯的溶解,同时增大了C4烷烯的界面存留率,不利于其界面扩散。另外,相比于非磺酸功能化离子液体(non-SFILs),磺酸功能化离子液体(SFILs)促进了C4烷烯的溶解,但抑制了C4烷烯的扩散。本文在C4烷基化界面性质方面的研究有利于深入理解C4烷基化过程,相关结果有望为烷基化过程强化和新型催化剂的优化和设计提供帮助。  相似文献   

9.
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。  相似文献   

10.
引入一种新的铁前体草酸亚铁,并考察4种制备方法(并流共沉淀,正加共沉淀,沉淀-浸渍K,沉淀-浸渍K、SiO2)对费托合成铁基催化剂晶体结构、物化性质以及催化性能的影响。研究发现,制备方法显著影响催化剂的晶体结构和织构性质,由并流共沉淀制备的催化剂由于具有较好的结晶度和还原性,并且助剂与活性相结合程度更为均匀,使得催化剂展现出最佳的活性和稳定性,CO转化率可达96.2%。还发现并流共沉淀制备的催化剂表现出较高的烃类产物收率和C2~C4烯烃选择性,对液相产物和固相产物进行碳数分析发现,并流共沉淀所得的液相产物中汽油组分的含量高达85.8%,且C4+重质烃产物中,C4~C18含量高达91.0%;正加共沉淀的液相产物中煤油组分的选择性较高;沉淀-浸渍K的液相产物中柴油组分含量较高。  相似文献   

11.
刘俊涛  滕加伟 《工业催化》2015,23(5):406-409
以ZSM-5分子筛为催化剂,碳五烃混合物为裂解原料,考察空速对碳五烃催化裂解制丙烯/乙烯反应性能的影响。结果表明,在580℃和实验空速范围,随着空速的增加,碳五烷烃及烯烃转化率整体呈下降趋势,但碳五烯烃转化率远高于碳五烷烃。乙烯及丙烯收率在空速3 h-1时达到最大,分别为10.51%和13.02%。碳四烯烃收率随空速的升高而降低,但各丁烯异构体相对于总烯烃的质量分布接近热力学平衡态。  相似文献   

12.
以廉价Cu-TEPA为模板剂合成Cu-SSZ-13分子筛,分别采用氯化铵和稀硝酸溶液对Cu-SSZ-13分子筛进行改性,制得几种甲醇制烯烃(MTO)催化剂。采用X射线衍射、X射线荧光分析、电感等离子体耦合质谱、87 K氩吸附、NH 3程序升温脱附和H 2程序升温还原等对催化剂结构进行表征,在微型固定床反应器中评价其MTO反应性能。结果表明,采用氯化铵溶液和稀硝酸溶液交换结合会降低催化剂中CuO及方沸石杂晶含量;使Cu-SSZ-13分子筛同时降低Na及Cu元素含量,获得更大的比表面积和适宜的酸强度及酸量,在MTO反应中有更长的催化寿命和更高的低碳烯烃选择性;Cu-SSZ-13分子筛的改性方式、比表面积、表面酸量、表面Cu的分布状态与催化性能密切相关。  相似文献   

13.
A series of HZSM-5 zeolites modified by different amounts of phosphorus (P/HZSM-5) were prepared. The physicochemical features of P/HZSM-5 catalysts were characterized by means of XRD, BET, NH3-TPD, FT-IR spectra of adsorbed pyridine, etc., and their performances for the catalytic cracking of the mixed C4 alkanes to produce light olefins were investigated. The results indicated that phosphorus (P) modification not only modulated the amount of acidic sites and the percentage of weak acidic sites in total acidic sites, but also regulated the acid type, i.e., the ratio of L/B (Lewis acid/Brönsted acid). The introduction of P also altered the basic characteristics of HZSM-5 which was evidenced by CO2-TPD analysis. Consequently, P modification with suitable amount was favorable for enhancing the selectivity to light olefins, especially to propene. At the temperature of 650 °C, the maximum yields of propene and ethene were achieved 25.6 and 33.9%, which were higher than those over parent HZSM-5 by 7 and 4.5%, respectively. Aromatics yield was found to be decreased with the increasing P loading due to the reduction of strong acid and the formation of new basic site which inhibited the hydrogen transfer reaction. All this indicates that P-modified HZSM-5 zeolites are effective catalysts for the cracking of mixed C4 alkanes to produce more light olefins.  相似文献   

14.
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.  相似文献   

15.
刘丹  陈星月  时一鸣  代成义  马晓迅 《化工进展》2020,39(11):4488-4496
在流化床反应器中,对Zn、Si和P改性的ZSM-5催化剂的甲醇制对二甲苯联产低碳烯烃的反应性能进行了研究。采用X射线衍射(XRD)、BET比表面积、扫描电镜(SEM)、NH3-程序升温脱附(NH3-TPD)等手段进行表征分析。结果表明,Zn改性使得催化剂酸强度降低,中强酸酸量增加,对二甲苯和低碳烯烃选择性都随之提高;一定量的硅沉积改性在降低催化剂外表面酸量的同时缩小孔口,浸渍适量P能够调变分子筛的酸中心强度和酸量,这都能够提高对二甲苯选择性。在流化床反应器中甲醇制对二甲苯联产低碳烯烃反应结果表明,3Zn-3Si-3P/ZSM-5催化剂在温度425℃、常压、反应时间40min、空速1h-1的条件下,对二甲苯在二甲苯中的选择性为76.0%,C2~C4低碳烯烃选择性为24.4%,特别是芳烃和C2~C4低碳烯烃的总选择性高达92.2%。  相似文献   

16.
Activated carbon-supported Pt-Cu, Pt-Ag, Pt-Co, Pt-Fe, and Pt catalyze the formation of oligomerization products from CF2Cl2 and H2 mixture (1:1 ratio) at 523 K. All catalysts deactivate with time on stream. The Pt-Co/C catalyst exhibits the highest selectivity toward C2–C3 hydrocarbons (50%), whereas Pt-Cu/C is the most selective toward tetrafluoroethylene (20%). The other catalysts (Pt, Pt-Ag, Pt-Fe) exhibit negligible oligomerization activity, CH4 and partially halogenated C1 molecules are the main products. The performance of each catalyst is understood in terms of the difference in the stability of bimetallic particles toward segregation under dechlorination conditions.  相似文献   

17.
The direct synthesis of olefins by CO2 hydrogenation with iron-based catalysts is one of the best ways to achieve CO2 emission reduction and CO2 conversion and utilization. At present, the CO2 hydrogenation activity and structural strength of the iron-based catalysts are still relatively low during CO2 hydrogenation process, which has become an important challenge for the industrialization of CO2 hydrogenation to olefins. In this work, a series of the supported iron-based catalyst was prepared by the impregnation method to study the influence of the properties of support materials on the structure of iron-based catalysts and the reactivities of the direct synthesis of olefins from CO2 hydrogenation. This work found that the support induced the iron species formed during the process of CO2 hydrogenation, simultaneously affected the order degree of carbon species on the surface of iron-based catalyst, and tuned the capability of CO2 adsorption and the activities of CO2 activation. The results shown that the Fe-based catalyst supported on ZrO2 exhibited the best catalytic performance for CO2 hydrogenation to olefins at 320℃ and 2.0 MPa. The CO2 conversion (>30%) and the selectivity of olefins in C2—C7 hydrocarbon products were as high as over 85%, the ratio of olefins to paraffins was 8.2, and the CO selectivity was 17.1%.  相似文献   

18.
考察焙烧温度对HZSM-5分子筛催化剂结构及1-丁烯齐聚性能的影响,采用XRD、SEM和NH3-TPD对催化剂进行表征。结果表明,升高焙烧温度,对HZSM-5分子筛催化剂的晶相和晶粒尺寸没有影响,催化剂中弱酸与强酸的酸强度和酸量均随焙烧温度的升高逐渐减弱。在催化剂晶粒尺寸一定条件下,催化剂酸性对催化剂的齐聚性能有较大影响,焙烧温度500℃时,C5+收率和C10+选择性最佳。  相似文献   

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