GB992548A - Process for carrying out chemical reactions by means of a ziegler catalyst - Google Patents

Abstract

In a process for carrying out a chemical reaction such as the polymerization of ethylene in which a Ziegler catalyst is passed into a reaction zone, the concentration of unpaired electrons in the liquid containing the catalyst and/or in the reaction vessel is measured by passing the material through the resonance cavity of an electron spin resonance apparatus. The process may be monitored periodically or continuously and the measuring apparatus output signal may be used to control the process to obtain a desired end product. A warning device may be operated. Zeigler catalyst is defined in relation to the Periodic Tables and the following process examples with electron measurements are given:- 1. A solution of TiCl4 in heptane and a solution of diethyl aluminium chloride in heptane are passed into a glass vessel under nitrogen, and ethylene is added after 1 hour. 2. A process as in (1) using wet nitrogen. 3. A process as in (1) in which a solution of ethanol in heptane is added to the catalyst solution. 4. A process as in (1) in which a solution of carbon tetrabromide in heptane is added to the catalyst solution. 5. A process as in (1) in which part of the nitrogen is replaced by dry air. Other catalyst components which may be used and provide indications of unpaired electron concentrations are :-di - isobutyl aluminium chloride, di-isobutyl aluminium hydride, methyl aluminium dichloride, dimethyl aluminium chloride, cyclo-pentadienyl titanium dichloride.