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1.
将四元催化剂体系(乙酰丙酮铬-膦胺型配体-助催化剂甲基铝氧烷-促进剂六氯乙烷)用于乙烯齐聚制1-辛烯反应,考察了促进剂、助催化剂、Al/Cr摩尔比、反应温度和反应压力等对催化剂的活性和1-辛烯的选择性的影响.结果表明,该四元催化剂体系比三元催化剂体系(铬化合物-膦胺型配体-甲基铝氧烷)对乙烯齐聚反应具有更高的1-辛烯选择性.产物除有1-辛烯外,还有较大量的1-己烯、甲基环戊烷和亚甲基环戊烷.甲基铝氧烷是高选择性生成1-辛烯必不可少的助催化剂.作为促进剂的六氯乙烷可以使乙酰丙酮铬更有利于催化乙烯齐聚反应生成1-辛烯.  相似文献   

2.
在小型固定流化床(FFB)装置上考察了Y与ZSM-5分子筛催化剂以及Y分子筛催化剂上温度、剂油比对全氢菲裂化环烷环开环反应的影响。结果表明,全氢菲在分子筛催化剂上通过环烷环开环反应生成环己烷、十氢萘等单环或双环环烷烃;单环或双环环烷烃进一步侧链断裂生成2-甲基戊烷、甲基己烷等异构烷烃等,异构化生成二甲基环戊烷、甲乙基环戊烷等烷基环戊烷,氢转移生成苯、甲苯、二甲苯等烷基苯,进行深度氢转移反应生成萘、烷基萘等双环芳烃;另外,全氢菲也会通过脱氢缩合生成菲、芘等三环以上芳烃甚至焦炭等。由于扩散和吸附性能的影响,其裂化开环反应的选择性在Y分子筛催化剂上比在ZSM-5分子筛催化剂上高。因此,全氢菲环烷环开环与脱氢缩合反应的相对比例(s(NRO)/s(DHC))在Y分子筛催化剂上较高;在Y分子筛催化剂上,温度为475~550 ℃、剂油比为3.0~9.0,反应温度升高或者剂油比增加,双分子氢转移以及脱氢缩合反应增强,导致环烷环开环反应产物选择性降低。  相似文献   

3.
以5-氨基邻甲酚与二苯基氯化膦为原料,通过取代反应合成了一种含有PNP和P—O结构的膦配体并确定了其结构.通过与Cr(acac)_3原位生成以及与Cr Cl3(THF)_3预制的方法制成配合物作为主催化剂,以甲基铝氧烷(MAO)为助催化剂,形成催化体系用于催化乙烯齐聚反应,考察了溶剂种类、反应温度、反应压力及Al/Cr摩尔比对该催化剂的活性和选择性的影响,并与原位生成的邻位和对位氨基酚类膦配体催化体系催化乙烯齐聚反应效果进行了对比.试验结果表明,以环己烷为溶剂,MAO为助催化剂,当反应温度为50℃、反应压力为2.5 MPa、Al/Cr摩尔比为700的条件下,该催化剂的活性最高达5.91×10~6 g/(mol·Cr·h),液相产物中1-辛烯选择性高达72.94%,1-己烯和1-辛烯总的选择性为82.11%.  相似文献   

4.
用HCl或HF对Re/H-ZSM-5催化剂进行了后处理,并在50~400 ℃用连续流动反应器研究了催化剂对环己烯加氢转化反应的影响. 与HCl处理相比, HF处理显著提高了催化剂上环己烯加氢生成环己烷以及甲基环戊烯加氢生成甲基环戊烷的催化活性,这主要是因为HF处理催化剂具有较高的铼分散度、酸中心数及酸强度. Re/H-ZSM-5(HF)催化剂上最高的酸中心强度使其具有最高的加氢裂化活性及最低的环己烯脱氢生成环己二烯活性. 在未处理的Re/H-ZSM -5催化剂上,沉积在分子筛载体孔道和空穴中非骨架Al和Si的量最少,因而对生成芳烃的脱氢反应具有最高活性. 卤化氢处理催化剂上二甲苯异构体的相对产量表明: HF处理催化剂上 ,对二甲苯产量高于间二甲苯;HCl处理催化剂上,间二甲苯和对二甲苯产量基本相?在未处理的催化剂上,间二甲苯量产量比对二甲苯高. 此外,上述所有催化剂上的邻二甲苯产量均约等于对二甲苯与间二甲苯之和.  相似文献   

5.
合成了3种新型的N取代基中含有O/N杂原子的1,3,5-三氮杂环己烷[NNN]型配体,利用氢核磁共振谱(1H NMR)、碳核磁共振谱(13C NMR)及电子轰击质谱(EI-MS)等方法对其进行表征.将[NNN]型配体与Cr(Ⅲ)络合制备相应的均相铬催化剂,采用电喷雾质谱(ESI-MS)及元素分析分别对其进行表征.以甲基烷氧铝(MAO)为助催化剂,考察了反应温度、反应压力及铝铬摩尔比等因素对催化乙烯齐聚催化性能的影响.研究结果表明,在以甲苯为溶剂,反应温度50℃,反应压力0.8 MPa,铝铬摩尔比为500∶1,Cr浓度为2.0×10-4mol/L的反应条件下,取代基为3-二甲氨基丙基的均相铬催化剂的催化活性能够达到15.71×105g/(mol Cr·h),对1-己烯和1-辛烯的选择性达到91.02%,而取代基为3-乙氧基丙基的均相铬催化剂的催化活性比较低,为11.54×105g/(mol Cr·h),但对1-己烯和1-辛烯的选择性较高,达到93.05%.  相似文献   

6.
研究发现Cp~2ZrL~2(L=Cl,Me,OC~6H~4-p-Me)/EAO(乙基铝氧烷)可同步催化乙烯齐聚-环化反应,不仅给出链状烯烃,而且生成环状剂聚物--亚甲基环戊烷。环状齐聚物的选择性取决于主催化剂的结构和浓度,反应介质,预反应温度和反应温度,反应时间,Al/Zr比及烷基铝水解程度等因素,加入碱性第三组分对催化活性和选择性亦有一定影响。在优化反应条件下,亚甲基环戊烷的选择性达到37%。  相似文献   

7.
王梅  李锐  钱明星  沈玉梅  王辉  何仁 《化学学报》2000,58(6):666-669
研究发现Cp~2ZrL~2(L=Cl,Me,OC~6H~4-p-Me)/EAO(乙基铝氧烷)可同步催化乙烯齐聚-环化反应,不仅给出链状烯烃,而且生成环状剂聚物--亚甲基环戊烷。环状齐聚物的选择性取决于主催化剂的结构和浓度,反应介质,预反应温度和反应温度,反应时间,Al/Zr比及烷基铝水解程度等因素,加入碱性第三组分对催化活性和选择性亦有一定影响。在优化反应条件下,亚甲基环戊烷的选择性达到37%。  相似文献   

8.
在小型固定流化床(FFB)装置中研究了Y分子筛与ZSM-5分子筛催化剂上的十氢萘裂化开环反应性能,考察了温度和剂油比对Y分子筛开环反应催化性能的影响。结果表明,十氢萘在分子筛催化剂上通过环烷环开环反应生成丙烷、丙烯、丁烷、丁烯、甲基戊烷和环戊烷、环己烷等非芳烃以及苯、C1~4烷基取代苯等单环芳烃,并通过脱氢缩合反应生成四氢萘、萘、甲基萘和菲、芘等多环芳烃甚至焦炭等。由于扩散和吸附性能的影响,ZSM-5分子筛催化剂的裂化开环反应选择性比Y分子筛催化剂的高,因此,十氢萘环烷环开环与脱氢缩合反应的相对比例(NRO/DHC)在ZSM-5分子筛催化剂上较高。在Y分子筛催化剂上,温度为450~550 ℃、剂油比为3~9,反应温度升高或者剂油比增加,双分子氢转移以及脱氢缩合反应增强,从而导致环烷环开环产物选择性降低。  相似文献   

9.
以1.0代聚酰胺-胺(PAMAM)为配体骨架,氯代二苯基膦为原料,通过取代反应合成了1种含有较大空间位阻的新型树枝状PNP配体,再以Cr Cl3(THF)3为络合试剂,通过络合反应合成树枝状PNP铬催化剂.采用傅里叶变换红外光谱(FTIR)、紫外-可见分光光度计(UV-Vis)、核磁共振波谱(NMR)、电喷雾电离质谱(ESI-MS)和元素分析等手段证实合成的新型树枝状PNP配体及其铬催化剂的结构与理论设计的结构一致.以甲基铝氧烷(MAO)为助催化剂,对乙烯齐聚反应进行了研究,考察了溶剂种类、反应温度、反应压力及Al/Cr摩尔比对该催化剂活性和选择性的影响.结果表明,以甲苯为溶剂,MAO为助催化剂,当反应温度为25℃,反应压力为0.9 MPa,Al/Cr摩尔比为500时,该催化剂的活性高达2.15×105g/(mol Cr·h),催化剂对乙烯三聚、四聚反应的选择性共达到36.76%.  相似文献   

10.
本文研究在氧化铝表面上,高分散度多金属值化剂金属相互作用和反应性能的关系。以正庚烷和甲基环戊烷为原料,模拟重整的芳构化和加氢裂解反应。发现在铂值化剂中加入金时甲基环戊烷氢解活性下降,芳构化选择性提高。在铱催化剂中加入金时,则氢解括性明显地提高,脱氢环化选择性下降。而铂、铱、金三元催化剂在芳构化选择性和稳定性方面都优于双组份或单组份催化剂。上述结果表明,各种金属的相互影响所产生的复杂效果对多金属催化剂选择性和稳定性的改变起重要作用。  相似文献   

11.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

12.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

13.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

14.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

15.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

16.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

17.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

18.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

19.
20.
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide.  相似文献   

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