CAJ | 학술논문

采用等体积浸渍法制备了不同K2 O、Li2 O 含量的 Pd﹣Au∕Al2 O3催化剂，采用低温氮吸附法、吡啶吸附红外光谱、程序升温还原（H2﹣TPR）等方法进行了表征研究。吡啶吸附红外光谱表征结果表明，催化剂表面只有L酸，无B酸，K2 O改性比Li2 O改性催化剂的表面酸性弱。H2﹣TPR表征结果表明，催化剂表面形成了Pd﹣Au二元合金，加入碱金属改性后，催化剂的还原峰向高温方向移动。以异戊二烯的模型化合物为原料评价了自制的改性Pd﹣Au∕Al2 O3催化剂的选择加氢性能，结果表明：催化剂经过Li2 O 改性后，异戊二烯的转化率和单烯烃选择性提高，而用K2 O改性时，异戊二烯的转化率降低，单烯烃选择性提高；采用K2 O质量分数为1．2％的催化剂，在反应温度为70℃时异戊二烯的转化率为90．0％，单烯烃的选择性为86．0％。
채용등체적침지법제비료불동K2 O、Li2 O 함량적 Pd﹣Au∕Al2 O3최화제，채용저온담흡부법、필정흡부홍외광보、정서승온환원（H2﹣TPR）등방법진행료표정연구。필정흡부홍외광보표정결과표명，최화제표면지유L산，무B산，K2 O개성비Li2 O개성최화제적표면산성약。H2﹣TPR표정결과표명，최화제표면형성료Pd﹣Au이원합금，가입감금속개성후，최화제적환원봉향고온방향이동。이이무이희적모형화합물위원료평개료자제적개성Pd﹣Au∕Al2 O3최화제적선택가경성능，결과표명：최화제경과Li2 O 개성후，이무이희적전화솔화단희경선택성제고，이용K2 O개성시，이무이희적전화솔강저，단희경선택성제고；채용K2 O질량분수위1．2％적최화제，재반응온도위70℃시이무이희적전화솔위90．0％，단희경적선택성위86．0％。
A series of Pd﹣Au∕Al2 O3 catalysts modified by different amount of alkali metal K or Li were prepared by incipient wetness impregnation and characterized by low temperature nitrogen adsorp﹣tion,FT﹣IR and H2﹣TPR techniques. The isoprene was used to evaluate the selective hydrogenation performance of the modified catalysts. The FT﹣IR results show that only Lewis acid sites exist on the catalysts,no Bronsted acid is found. The acid strength of K﹣modified catalyst is weaker than Li﹣modi﹣fied catalyst. The H2﹣TPR results indicate that Pd﹣Au binary alloy is formed,the reduction peaks of catalysts shift to higher temperature after modified by alkali metals. The reaction results of isoprene se﹣lective hydrogenation on the modified Pd﹣Au∕Al2 O3 catalysts show that the isoprene conversion and iso﹣pentenes selectivity increase when addition of K2 O. The LiO modification reduces the conversion of iso﹣prene but isopentenes selectivity increases. At 70 ℃,isoprene conversion reaches 90. 0%,isopentenes selectivity is 86. 0% on the catalyst Pd﹣Au∕Al2 O3 with 1. 2% K2 O.