Highly Branched Polyethylene with Low Molecular Weight Prepared through Ethylene Polymerization on Nickel-Based Catalyst

Nickel-based catalyst [N,N]NiBr2, in which [N,N] stands for N-(2,6-diisopropylphenyl)pyridine-2-carboxaldimine, shows high activity for ethylene polymerization in the presence of organoaluminum compounds under high ethylene pressure to yield polyethylene characteristic of low molecular weight and highly branched chains. Toluene as the solvent is more in favor of catalyst activity, higher molecular weight and branched chains in polyethylene structure as compared to hexane solvent.     

One-step synthesis of N-methylaniline by hydroalkylation of nitrobenzene over oxide catalysts

The reaction of nitrobenzene hydroalkylation with methanol forming N-methylaniline as the main product has been studied. Alumina modified with copper and chromium compounds deposited by incipient wetness impregnation has been examined as the catalyst. It has been shown that the reductive alkylation of nitrobenzene with methanol is preferable to conduct at a temperature of 250°C, a feed weight hourly space velocity of 1 to 2 h^?1, a methanol: nitrobenzene molar ratio of 3 to 4, and hydrogen: nitrobenzene molar ratio of 3–6. It has been found that promotion of the copper-containing catalyst with chromium leads to enhancement of the catalyst activity and facilitates an increase in selectivity for N-methylaniline.     

Tetramerization of ethylene to octene-1 (a review)

Data on the activity, selectivity, and reaction conditions for the selective oligomerization of ethylene to octene-1 mediated by chromium-containing organic compounds in combination with organoaluminum compounds have been summarized and analyzed. Possible schemes for the mechanism of the formation of octene-1 and byproduct cyclic hydrocarbons (methylenecyclopentane and methylcyclopentane) and higher (>C₈) linear olefins have been briefly discussed.     

Synthesis and study of antistatic diesel additives based on petroleum acids

Various alkyl nitronitrates based on individual olefins and mixtures of propylene trimer and tetramer isomers have been derived. Hydroxyesters have been synthesized via the reaction of natural naphthenic acid with propylene oxide in different molar ratios, as have complexes of chromium, nickel, and cobalt salts of natural naphthenic acids with alkyl nitronitrates. The electric conductivity of 0.001% solutions of nitro compounds in diesel fuels has been examined. It has been found that the antistatic properties of the chromium and nickel salts prevail, with the greatest antistatic effect being displayed by the complexes of the chromium salt. Hydroxyesters in a 1: 1 molar ratio also exhibit a strong antistatic effect.     

微波辐射相转移催化合成对羟基苯甲酸苄酯

采用微波辐射相转移催化技术,以四丁基溴化铵为相转移催化剂,先将对羟基苯甲酸与碳酸钾成盐,在无有机溶剂和无机载体的条件下与氯化苄直接酯化合成对羟基苯甲酸苄酯。实验结果表明,该方法具有操作简单、反应速率快、后处理方便、产率高等优点。在微波输出功率350W、辐射时间4min、n(对羟基苯甲酸)/n(氯化苄)=1/1 75、n四丁基溴化铵/n(对羟基苯甲酸)=0 024的优化条件下,产率可达98 2%。     

A Catalyst for Hydrogenation of Middle Distillates

A catalyst is proposed for hydrogenation of middle distillates. The results of testing it are reported. It is shown that this catalyst is more resistant to sulfur–containing compounds and ensures hydrogenation of aromatic hydrocarbons in mild conditions. In contrast to existing industrial catalysts that contain nickel, chromium, etc., as hydrogenating components, hydrogenation can be conducted on the proposed catalyst without preliminary hydrotreating.     

微波辐射季铵盐催化合成3-苯基丙烯酸乙酯

介绍了用微波辐射反应技术合成3-苯基丙烯酸乙酯的方法。考察了微波输出功率、辐射反应时间、载体品种、相转移催化剂品种以及反应物摩尔比对3-苯基丙烯酸乙酯收率的影响。结果表明,在微波输出功率500W、辐射时间4．0min、以三氯化二铝为载体、季铵盐四丁基溴化铵为相转移催化剂、反应物3-苯基丙烯酸钾与氯乙烷摩尔比1：1．2的最佳反应条件下,3-苯基丙烯酸乙酯收率达93．1％。     

Ethylene oligomerization mediated by iron formazanates and organoaluminum compounds

A number of iron(II) complexes have been synthesized on the basis of benzothiazolylformazans, and their structure and composition have been characterized by elemental analysis, mass spectrometry, and X-ray analysis. The catalytic behavior of Fe(II) formazanates in the reaction of ethylene oligomerization in the presence of various organoaluminum compounds has been studied. Methylaluminoxane facilitates the formation of α-olefins (butene-1, hexene-1) and the byproducts hexene isomers; ethylaluminum dichloride (AlC₂H₅Cl₂) increases the selectivity for alkyltoluenes.     

微波法合成含二茂铁基查尔酮

实验以微波法合成一种含二茂铁基查尔酮。讨论了催化剂、反应物料摩尔比、反应时间、微波辐射功率等对产率的影响。实验结果表明,微波法合成二茂铁基查尔酮的最佳条件为:催化剂为KF/Al_2O_3,n(乙酰基二茂铁):n(苯甲醛)=1:1.2,反应时间为4 min,微波辐射功率为140 W。微波法合成二茂铁基查尔酮的产率达86.7%。目标产物结构经IR,~1H NMR进行了验证。     

金属氧化物对低铬铁系催化剂结构和性能的影响

运用程序升温还原（ＴＰＲ）、Ｘ射线衍射（ＸＲＤ）及活性评价技术研究了金属氧化物对低铬铁系催化剂结构和性能的影响。结果表明，ＣｅＯ２能提高铁系催化剂的活性，而Ｂｉ２Ｏ３能进入Ｆｅ２Ｏ３内部，既能提高催化剂的活性，又能增强催化剂的稳定性     

正交设计在乙酸正丁酯合成中的应用

以乙酸和正丁醇为原料,低相对分子质量壳聚糖负载硫酸盐为催化剂,采用微波加热法合成乙酸正丁酯。利用正交设计法通过方差分析,探讨了催化剂用量、微波辐射功率和微波辐射时间及他们之间的交互作用对酯化率的影响。结果表明,微波辐射时间对酯化率的影响高度显著,催化剂用量和微波辐射功率的改变对酯化率影响显著,而且这三个因素之间存在交互作用, 当催化剂用量为1.0%、微波辐射功率为265 W、微波辐射时间为15 min时,乙酸正丁酯的酯化率达96%以上。     

影响聚乙烯催化剂QCP—01聚合活性及产物熔体流动指数的因素

考察了聚合条件以及催化剂配方和制备工艺条件对气相法铬系聚乙烯催化剂ＱＣＰ－０１的聚合活性及产物熔体流动指数的影响。试验结果表明,提高聚合反应温度、压力、铬含量,降低硅胶脱水温度和催化剂活化温度有利于提高聚合物的熔体流动指数。     

Ag^＋、Ni^2＋改性复合钛铌酸钾盐对二甲基硫和乙硫醇吸附与光催化氧化研究

由高温固相法制备复合钛铌酸钾盐,通过Ag^＋和Ni^2＋离子交换对其进行改性。采用红外光谱方法考察Ag^＋与Ni^2＋离子改性的复合钛铌酸盐对二甲基硫（DMS）和乙硫醇（EM）的吸附特征与光催化氧化作用。结果表明,复合钛铌酸盐对DMS与EM的吸附与光催化氧化行为取决于分子中S原子的环境与复合钛铌酸盐中阳离子的性质。DMS同Ag^＋与Ni^2＋离子改性的钛铌酸钾盐表面相互作用较弱,在自然光辐射下稳定,而EM同Ag^＋离子改性的钛铌酸盐具有明显的相互作用,即使在自然光辐射下也可被氧化。在紫外光辐射下,DMS和EM在两种离子改性的钛铌酸钾盐上均被催化氧化,DMS被氧化至亚砜、砜和硫酸酯,而EM被氧化至磺酸。     

微波辐射合成β-二酮类化合物

采用微波辐射新技术,以芳香酮和芳香酯为原料,在强碱作用下经Claisen缩合,合成了4种β-二酮类化合物(4-叔丁基-4′-甲氧基二苯甲酰甲烷、4-甲氧基二苯甲酰甲烷、4-叔丁基二苯甲酰甲烷、二苯甲酰甲烷)。4-叔丁基-4′-甲氧基二苯甲酰甲烷的较佳合成工艺条件为:甲苯为溶剂,NaNH_2为催化剂,n(对甲氧基苯乙酮) :n(对叔丁基苯甲酸甲酯):n(NaNH_2)=1:2:5,微波功率320 W,回流反应45 min,产率达83%。4种化合物均用红外光谱、核磁共振和紫外光谱进行了结构表征。化合物在300～400nm的紫外光区有强烈吸收,是一类良好的紫外线吸收剂。     

微波辐射相转移催化合成苹果酯-B

采用微波辐射相转移催化技术,以四丁基溴化铵为相转移催化剂、乙酰乙酸乙酯和1,2-丙二醇为原料,柠檬酸为酸催化剂,在无有机溶剂存在下用单因素实验法和正交实验法研究了微波辐射功率、辐射时间、催化剂的类型和用量及反应物的摩尔比等因素对苹果酯-B收率的影响。实验结果表明,在微波辐射功率210W、辐射时间6m in、n(乙酰乙酸乙酯)∶n(1,2-丙二醇)=1.00∶2.00、n(柠檬酸)∶n(乙酰乙酸乙酯)=0.05的优化条件下,苹果酯-B的收率可达91.2%。     

浅析硅胶在Unipol气相法聚乙烯工艺中的作用

分析了在Unipol气相法聚乙烯工艺中,由钛系M催化剂向铬系F、S催化剂切换时系统中产生的催化剂毒物以及毒物的消除原理、毒物吸附剂的选择,同时阐述了工业装置切换过程中硅胶注入量的确定方法。     

一种用于正戊烷异构化的超强酸催化剂的合成与表征

以水合无机硝酸锆为锆源、水合氯化铬为铬源,采用直接合成法制备含铬介孔氧化锆分子筛,并分别将纯相介孔氧化锆和掺铬介孔氧化锆经硫酸溶液浸渍制备相应的固体超强酸;采用X射线衍射、氨程序升温脱附等方法对所制分子筛及超强酸的物相及表面酸性进行表征,考察铬的掺入量及三乙醇胺的加入对合成产物的物相及性能的影响,并对超强酸催化正戊烷异构化反应活性进行评价。结果表明：铬的掺入使得氧化锆的四方相稳定存在,减少了向单斜相转化的可能性,增加了介孔氧化锆的热稳定性;三乙醇胺的加入使得含铬介孔材料的有序度增加,并有利于铬的均匀分散;在介孔氧化锆中掺铬后增加了固体超强酸的催化活性,不论是正戊烷转化率还是异戊烷选择性及收率都非常稳定,产物异戊烷的选择性在40 %左右、收率在10 %左右。     

微波辐射壳聚糖硫酸盐催化合成乙酸正丁酯

采用微波辐射技术,以壳聚糖硫酸盐为酯化反应催化剂合成乙酸正丁酯。利用正交实验设计和单因素实验考察了微波辐射功率、微波辐射时间、催化剂用量、反应物配比等因素对酯化反应的影响。实验结果表明,壳聚糖硫酸盐催化剂在乙酸正丁酯的合成中显示出较好的催化效果,而且该法具有操作简便、反应速率快、节约能源等优点,在冰醋酸用量4.17mL、微波输出功率260W、辐射时间15min、催化剂质量分数1.0%、n(正丁醇)∶n(乙酸)=3∶2的优化条件下,酯化率可达96.1%。     

整体式甲烷燃烧催化剂的活性研究

研究了以Co、Cr、Mn、Fe和Ni的单一或混合氧化物为活性组分的整体式催化剂在甲烷燃烧反应中的活性。整体式催化剂直径为 10mm ,长 15mm ,测试温度范围为 30 0 - 70 0℃。结果显示 ,单一氧化物中Co、Cr和Mn的活性较好 ,Fe和Ni的活性较差 ;混合氧化物催化剂均表现出较高的活性 ,但以含Co、Cr、Mn的 3组分混合氧化物催化剂为更佳。同时考察了空速、烷氧比、稀释气、温度等因素对甲烷燃烧反应的影响。在烷氧比为 1:4,稀释气含量约为 6 0 % ,反应温度 6 5 0℃ ,大空速下甲烷转化率较高。     

气相法聚乙烯催化剂QCP-02的反应行为及反应动力学

采用微机控制的气相搅拌床反应器对实验室自制的还原型铬催化剂ＱＣＰ－０２进行了聚合反应行为和动力学研究。讨论了还原剂种类以及聚合反应的温度和压力对催化剂的活性和所生成产品性能的影响。当反应压力为０９～１６ＭＰａ时,最大聚合反应速率与乙烯压力呈一级动力学关系,并据此求出反应温度为８０～９５℃时ＱＣＰ－０２催化剂上乙烯均聚反应的表观活化能。