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本文研究了H_3PW_(12)O_(40)及其Na~+、Al~(3+)、Cd~(2+)、La~(3+)盐对乙苯氧化脱氢反应的催化活性。发现活性与酸强度和酸量之间没有直接的关系。杂多酸及其盐类在反应开始阶段均存在一段活性增长期,简称为“增活期”。增活期内催化剂表面的积炭量逐渐增加,积炭物的H/C比逐渐减小。用质谱法、薄板层析法检知了积炭物中有醌类物质存在,提出了积炭物中的醌类基团是氧化肥氢的活性中心的观点。
In this paper, the catalytic activities of H_3PW_ (12) O_ (40) and its Na ~ +, Al ~ (3 +), Cd ~ (2+) and La ~ (3 +) salts for the oxidative dehydrogenation of ethylbenzene were studied. There is no direct relationship between activity and acid strength and acidity. Heteropoly acid and its salts in the initial stage of the reaction there is a period of activity of growth, referred to as the “active phase.” The amount of coke deposited on the catalyst surface increased gradually during the active period, and the H / C ratio of the coke decreased gradually. Mass spectrometry and thin-layer chromatography were used to detect the presence of quinone in the coke, suggesting that the quinone groups in the coke were the active centers of the hydrogen fertilizers.