氧化鉻觸媒之ESR光譜及其對丙烯聚合之活性

ESR Spectrum of Chromium Oxide Catalysts and its Activity on Propylene Polymerization

施鑑洲(Chieh-Chou Shin)

《化學》 55年2期 (1966/06) Pp. 61-67

https://doi.org/10.6623/chem.1966010

摘要

將鉻含量，焙燒溫度，組成以及擔體各異之氧化鉻觸媒，以電子自轉共鳴(electron spin resonance，以下簡稱ESR)光譜吸收及化學分析等方法，分別測定其五價鉻(Cr^(5+))之ESR信號強度(signal strength)與六價鉻(Cr^(6+))之含量，並於低壓氣相下進行丙烯聚合，以探求初期聚合時之活性與活化過程中五價鉻強度與六價鉻含量間之相互關係。用同一擔體與相異之鉻含量觸媒進行聚合時，其活性與五價鉻之ESR信號強度間有相互關係，但如用不同之擔體則兩者之間並無關聯。在各種氧化鉻觸媒中六價鉻之含量與活性之間存有相當比例關係，故丙烯在低壓氣相聚合時，六價鉻較五價鉻更具影響，同時六價鉻之含量與活性亦對之有密切關係。

並列摘要

The ESR signal strength of Cr^(5+) and the content of Cr^(6+) for various chromium oxide catalysts, such as those containing different chromium content, calcined at different temperature and supported on various carriers, were determined by ESR measurements and chemical analysis methods, respectively. Low pressure vapor-phase polymerization of propylene over various chromium oxide catalysts was undertaken to investigate, under activation process, the correlations among Cr^(5+) signal strength, Cr^(6+) content, and activity in the initial polymerization. There is a correlation between the catalytic activity and the ESR signal strength of Cr^(5+) for chromium oxide catalysts supported on the same carrier, but no correlation on the different carriers. A nearly linear relation was found between the activity and the content of Cr^(6+) in various chromium oxide catalysts. Cr^(6+) is, therefore, more effective than Cr^(6+) for the polymerization of propylene at low pressure and in the gas phase, and, furthermore, the activity of the catalyst has close relation to the content of Cr^(6+).