Catalysys and Surface Science

Heinz Heinemann, Gabor A. Somorjai

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9781351462259
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

The most comprehensive and up-to-date survey of five industrially important areas ofcatalysis, Catalysis and Surface Science focuses on chemicals from methanol ... hydrotreatingof hydrocarbons . . . catalyst preparation ... monomers and polymers ... andphotocatalysis and photovoltaics.In each of these significant topics, this useful collection of articles traces state-of-the-artdevelopments in fundamental science ... in current exploratory and applied research ...and in current technology. It outlines future trends in catalytic research and technology,and gathers together and synthesizes-into one, single, handy reference-the informationcontained in voluminous, widely scattered articles, books, and patents. As added referencefeatures, this authoritative source provides a wealth of illustrations, including photographs,charts, tables, and line drawings .. . plus useful, detailed bibliographies for further research.Written by 32 leading authorities on all aspects of catalysis, Catalysis and Surface Scienceis essential reading for chemical, industrial process, petrochemical, and electronicengineers, as well as industrial, polymer, and materials chemists. It is also a useful text forgraduate students in chemistry and chemical engineering.

Monomers and Polymers

Studies with High Activity Catalysts for Olefin Polymerization

FREDERICK J. KAROL

UNIPOL Systems Department Union Carbide Corporation Bound Brook, New Jersey

I.	INTRODUCTION
II.	TYPES OF HIGH ACTIVITY CATALYSTS
III.	PREPARATIVE METHODS TO HIGH ACTIVITY CATALYSTS
	A.	Chemical Anchoring to Surface of Substrate
	B.	Formation of Bimetallic Complexes
	C.	Insertion into Defects of Substrate
	D.	Formation of High Surface Area Sponges
	E.	Formation of Solid Solutions by Cocrystallization
IV.	ACTIVE SITE CONCENTRATIONS
V.	LIGAND EFFECTS ON CATALYTIC BEHAVIOR
VI.	FACTORS IN CONTROL OF MOLECULAR WEIGHT DISTRIBUTION
VII.	STEREOREGULARITY AND PROPYLENE POLYMERIZATION CATALYSTS
VIII.	CATALYST CHARACTERIZATION STUDIES
IX.	EFFECTS OF CATALYST MORPHOLOGY ON POLYMER MORPHOLOGY
X.	MECHANISM OF OLEFIN POLYMERIZATION
XI.	CATALYSIS AND THE POLYETHYLENE REVOLUTION
XII.	CONCLUDING REMARKS REFERENCES

I. INTRODUCTION

Catalysis continues to play a vital role in polymerization of such olefins as ethylene and propylene. A voluminous patent and scientific literature describing transition metal catalysts for olefin polymerization has emerged since the original discoveries by Ziegler, Natta, and other workers [1, 2, 3, 4, 5, 6], Significant progress in polymerization catalysis has been made in the last 15 years, particularly with the development of methods to increase the efficiency of transition metal catalysts in olefin polymerization. Success in this area has provided the basis of simplified, less costly plant operations which do not require removal of residual catalyst from the polymer [3, 4, 5, 6, 7, 8, 9].

Although much attention has been directed toward improvements in catalyst productivity, there has been and continues to be much active research on other important features of olefin polymerization. The specific nature of the catalyst has an important effect on polymer molecular weight, polymer molecular weight distribution, copolymerization kinetics, and degree of stereoregularity. Moreover, the size, shape, and porosity (morphology) of the catalyst particle play an important role in regulating the morphology of the resultant polymer [6, 7, 8, 9]. Many modern day industrial catalysts show attractive behavior in most or all of the areas described above.

While significant technological advances based on new and improved catalysts have been made since the original discoveries, there is still a widely held view that understanding of these catalysts is meager and empirical. It is true that olefin catalytic processes are not generally understood in a detailed mechanistic sense. One cannot predict a priori the behavior of a particular catalyst composition or the specific characteristics of the polymer produced by the catalyst. Nevertheless, significant progress has been made through studies with a wide variety of high activity catalysts. Certain general requirements have been identified to be critical in polymerization. This paper reviews segments of current catalyst research activities in olefin polymerization and discusses some current perspectives in these research areas.

II. TYPES OF HIGH ACTIVITY CATALYSTS

Developments toward higher activity (≥200 kg polymer/g Ti versus 1-5 kg polymer/g Ti) Ziegler-Natta catalysts have been based in large part on reactions of specific magnesium, titanium, and aluminum compounds [2, 3, 6, 10]. Some of the early impetus in this area was provided by catalysts, chemically anchored on Mg(OH)Cl supports [11]. Other studies concentrated on the use of MgCl₂ as a substrate [12, 13, 14]. Grinding of MgCl₂, and treatment with TiCl₄, provided one route to a higher surface area substrate of magnesium and titanium. Some developments focused on reaction products of magnesium alkyls and titanium compounds [15]. Other workers described the advantages of preparing trimetallic sponges by the addition of certain aluminum compounds to a magnesium substrate which had been treated with a titanium compound [16]. Catalysts based on reaction of magnesium alkoxides with transition metal compounds have also received attention [17]. Chemical complexes consisting of magnesium and titanium compounds with electron donors also serve to catalyze olefin polymerization [18].

Attractive, high activity catalysts for propylene polymerization have been described. Patents to Montedison/Mitsui discuss catalysts comprising an aluminum alkyl compound with an electron donor such as ethylbenzoate, and a solid matrix containing the reaction products of halogenated magnesium comp...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Contributors
• CHEMICALS FROM METHANOL
• HYDROTREATING OF HYDROCARBONS
• CATALYST PREPARATION
• MONOMERS AND POLYMERS
• PHOTOCATALYSIS AND PHOTOVOLTAICS
• Index