改性AlPO4分子筛的催化作用

0 引言 磷酸铝分子筛是一类具有潜在用途的新型分子筛。为探索其在催化领域中的应用,本文对水热晶化法合成出的AlPO_4-5分子筛经改性作为甲苯歧化反应催化剂,测定其催化活性。1 实验部分1.1 样品和试剂 将活性水合氧化铝(抚顺石油三厂生产)和磷酸,按一定比例与蒸馏水中经搅拌形成胶体。然后加入Et_3N,再搅拌均匀后     

中孔分子筛催化剂的研究进展

从4个方面回顾中孔分子筛催化剂的研究进展①代替传统酸催化剂催化大分子裂解,Friedel-Crafts的烷基化和酰基化反应;②向其骨架中引入Na+,Cs+等碱金属离子制得碱性催化剂催化Knoevenagel缩合反应;③引入Ti,Sn及Pt等过渡金属元素制得氧化还原催化剂以提高对大分子氧化反应的选择性;④负载其他活性物质.指出今后应在增加“中孔墙”的结晶度,增强酸性和增大孔径等方面做进一步的研究.     

PZSM-5分子筛催化剂用于烯烃催化裂解的研究

以固定流化床研究了不同磷含量改性的ZSM-5分子筛对混合₄烯烃催化裂解性能的影响,并以适当磷含量的催化剂进行了工艺条件试验。试验表明,磷与ZSM-5分子筛骨架中的羟基发生了化学作用,改善了催化剂的催化性能及水热稳定性;高负荷、高水比及适当增加磷的负载量,可以抑制烯烃裂解的氢转移反应,有利于提高丙烯选择性。     

新型含钛分子筛催化剂合成及应用评述

笔者通过对合成舍钛分子筛的影响因素如模板剂、钛源、硅源、碱源等系统分析，并对舍钛分子筛在选择氧化反应的催化性能方面加以评价，为乙苯氧化脱氢制苯乙烯催化荆设计及研制提出了新思路。     

催化新材料—钛硅分子筛的制备与应用

对具有独特氧化性能的含钛分子筛的制备和应用进行了述评,简述了ＴＳ－１,ＴＳ－２,Ｔｉ－ＭＣＭ－４,Ｔｉ－ＨＭＳ,Ｔｉ－β型等含钛分子筛的合成及合成中不同的硅源,钛源,模板剂,合成条件对结构性能的影响。介绍了含钛分子筛在苯与苯酚的羟基化,烯烃的环氧化,环己酮的肟化,妥和饱和烃的氧化等反应中的应用及催化的作用机理,并对钛硅分子筛研究中存在的问题和应用前景提出了看法。     

Fe-MEL分子筛催化剂的制备及其催化脱色

按摩尔比SiO2:TBAOH(四丁基氢氧化铵):H2O=1:0.35:53水热合成了MEL分子筛,并以机械研磨法制备了Fe-MEL分子筛催化剂,对其进行了表征,研究了其催化H2O2降解染料废水的性能,考察了染料废水初始浓度、pH值、催化剂投加量、H2O2用量、反应时间对降解效果的影响. 结果表明,在染料浓度30 mg/L及pH 6、催化剂投加量3.75 g/L和30%(w) H2O2加入量37.5 mL/L、反应时间2.5 h的优化条件下,染料废水脱色率达97.8%.     

烃类异构化分子筛催化剂的反应性能研究

合成了具有EUO拓扑结构的FZ-10分子筛,并对其进行改性研究,考察了催化剂酸强度分布和酸量对二甲苯异构反应性能的影响规律.结果表明:中等强度B酸中心数目较多的FCZ-102催化剂表现了更好的C8芳烃收率和乙苯转化率,当二甲苯异构体接近热力学平衡组成、乙苯转化率为27％时,C8芳烃收率达到98％以上.     

微细NaY分子筛的研究进展

介绍了近年来微细NaY分子筛的合成、表征、改性及其在催化等方面的进展，以期这种新型换代催化剂得到进一步的深入研究和广泛应用。     

稀土-Cu-K/Y分子筛催化剂的制备与性能研究

采用浸渍法制备了分别以Y型分子筛和γ-Al2O3为载体的几种含铈、镨、钕的氯化氢氧化催化剂.运用XRD、ESEM、BET等不同测试手段对两种催化剂进行了表征,测试了这两种催化剂对于氯化氢氧化反应的活性.XRD检测结果表明:以γ-Al2O3为载体的催化剂表面形成了明显的稀土氧化物及氯化钾晶相的特征衍射峰,且主要以CeO2相存在,而以Y型分子筛为载体的催化剂表面并没有检测到相关的物相;ESEM检测表明在Y型分子筛中引入铜、钾及稀土元素后并没有破坏Y型分子筛的结构.在氯化氢氧化反应中,稀土-Cu-K/Y显示了良好的催化活性,在648 K,V(HCl)/V(O2)＝1.5的条件下,氯化氢的转化率达到了85%.     

柠檬酸处理对β沸石结构、酸性和催化性能的影响

采用XRF、XRD、FT-IR、NH3-TPD等手段对柠檬酸处理后的β沸石进行表征，同时以苯和丙烯的烷基化反应为探针，考察了柠檬酸处理后的β沸石的催化性能。结果表明：柠檬酸处理对β沸石具有脱铝功能的同时，也具有补铝的功能；柠檬酸处理后的β沸石的总酸量和B酸量增加，酸强度增强；对苯和丙烯烷基化反应的催化活性提高。     

等离子体技术在分子筛催化中的应用

本文简单介绍了等离子体的特性,着重概述了等离子体技术在分子筛催化剂制备、再生、改性以及促进分子筛催化等方面的应用。     

橡胶油烃类结构组成对热熔压敏胶性能的影响

以环烷基基础油和链烷基基础油调合配制的不同烃类结构组成的橡胶油作热熔压敏胶（HMPSA）的增塑剂,研究橡胶油烃类结构组成对HMPSA持粘性和剥离强度的影响。结果表明：橡胶油中环烷烃含量越大,HMPSA的持粘性越好,180^°剥离强度越大。     

Direct Evidence for a Catalytically Active Role of the Hydrocarbon Pool Formed on Zeolite H-ZSM-5 During the Methanol-to-Olefin Conversion

The catalytic role of the hydrocarbon pool formed during the conversion of methanol on zeolite H-ZSM-5 was investigated by in situ MAS NMR spectroscopy under continuous-flow (CF) conditions and by changing of the methanol feed from ¹³CH₃OH to ¹²CH₃OH under steady state conditions. Utilizing this experimental approach, a decrease of the ¹³C CF MAS NMR signals of alkyl groups bound at the olefinic and aromatic skeleton atoms of the hydrocarbon pool by 40% was observed. Simultaneously performed ¹H CF MAS NMR measurements ensured that the total amount of carboneous compounds on the zeolite catalyst was constant during the experiments. The decrease of the number of ¹³C-isotopes of alkyl groups, observed after changing the ¹³C-enrichment of the methanol feed, is the first direct evidence for the side-chain methylation of olefinic and aromatic skeleton carbon atoms as an important pathway of the hydrocarbon pool mechanism for the methanol-to-olefin conversion on acidic zeolites.     

T型沸石的合成及其在催化方面的研究进展

T型沸石具有高的热稳定性,可用作催化和吸附材料,用于工业催化工业烃类生产、吸附领域。介绍了T型沸石合成过程中原料、组成、晶化温度和时间、模板剂等合成条件对合成产物性能的影响,介绍了表征T型沸石的方法和手段,对T型沸石在工业催化等领域的应用进行了总结,对T型沸石的工业前景进行了展望。     

Unifying Principles in Zeolite Chemistry and Catalysis

Abstract

In recent years molecular sieve catalysts have assumed an increasingly important role in industrial catalysis, Applications of zeolite catalysts are expanding from the traditional petroleum refining to new and improved fuel processing applications, and to new roles in both the petrochemical and chemical industries. Up to the present, all commercial applications of zeolite catalysts have been carried out with aciaic zeolites. Recent investigations of zeolite chemistry revealed several important features which appear common to both alkali and acidic zeolites. This new chemical evidence raises the possibility that the underlying physicochemical features of both types of zeolites play a role in catalysis.     

Unifying Principles in Zeolite Chemistry and Catalysis

In recent years molecular sieve catalysts have assumed an increasingly important role in industrial catalysis, Applications of zeolite catalysts are expanding from the traditional petroleum refining to new and improved fuel processing applications, and to new roles in both the petrochemical and chemical industries. Up to the present, all commercial applications of zeolite catalysts have been carried out with aciaic zeolites. Recent investigations of zeolite chemistry revealed several important features which appear common to both alkali and acidic zeolites. This new chemical evidence raises the possibility that the underlying physicochemical features of both types of zeolites play a role in catalysis.     

High Yield Conversion of Residual Pentoses into Furfural via Zeolite Catalysis and Catalytic Hydrogenation of Furfural to 2-Methylfuran

Xylose was dehydrated over (H⁺) mordenite, using a continuous two-liquid-phase (aqueous-toluene) plug-flow reactor at 260 °C and 55 atm, with 98% conversion rate, 98% furfural molar yield, and 98% furfural selectivity (results from the first pass). Furfural in toluene was hydrogenated over a Cu/Fe catalyst, at 252 °C (gas-phase), in a 99% conversion rate to give 2-methylfuran in a 98% yield (same activity maintained for a 20-h operation).     

One Pot Direct Catalytic Conversion of Cellulose to Hydrocarbon by Decarbonation Using Pt/H-beta Zeolite Catalyst at Low Temperature

We investigated one pot direct catalytic conversion of cellulose to light hydrocarbon selectively at low temperature in the presence of Pt and solid-acid zeolite catalysts. Results revealed that Pt/H-beta zeolite catalyst prepared by ion exchange enabled selective production of C₃ and C₄ hydrocarbons.     

Reaction Mechanisms of Lean-Burn Hydrocarbon SCR over Zeolite Catalysts

A large number of novel fatty compounds have been synthesized by catalytic C,C-bond forming addition reactions to the C,C-double bond of unsaturated fatty compounds. Radical reactions such as the solvent-free addition of α-halocarboxylic acid esters initiated by electron transfer, e.g., from copper to give fat-derived γ-lactones are described as well as Lewis acid–induced electrophilic addition reactions yielding new oleochemicals such as alkyl-substituted 4-chlorotetrahydropyrans, primary homoallylic alcohols, β-, γ-unsaturated ketocarboxylic acids and Diels–Alder addition products. New catalysts as, e.g., ligand-modified rhodium catalysts for the hydroformylation and heterogeneous boron-modified rhenium catalysts for the olefin metathesis have been developed. The addition of C-nucleophiles such as dimethylmalonate and nitromethane is possible by palladium-(0)catalyzed additions to unsaturated fatty compounds after conversion of the electron-rich to an electron-poor double bond. More than fifty literature articles are reviewed.