过渡金属修饰的磷钨酸盐催化剂在Friedel-Crafts乙酰化反应中的应用

制备了过渡金属修饰的磷钨酸盐(M_xH_(3-2x)PW_(12)O_(40),M=Co,Cu,Zn,Ni)催化剂,用BET,ICP,XRD,FTIR,NH_3-TPD等技术对其性能进行了表征,并考察了该系列催化剂在芳香类化合物的Friedel-Crafts乙酰化反应中的活性。实验结果表明,多孔性M_xH_(3-2x)PW_(12)O_(40)保持了磷钨酸的Keggin结构和酸强度,酸量明显大于磷钨酸。在茴香醚乙酰化反应中,M_xH_(3-2x)PW_(12)O_(40)(除Co_(1.5)PW_(12)O_(40)外)的催化活性和选择性明显高于磷钨酸和Cs_(2.5)H_(0.5)PW_(12)O_(40),其中Co_(0.5)H_2PW_(12)O_(40)的催化活性最高。以Co_(0.5)H_2PW_(12)O_(40)为催化剂合成对甲氧基苯乙酮(p-MOPA)时,P-MOPA收率和选择性分别达到84.36%和96.78%。Co_(0.5)H_2PW_(12)O_(40)用于苯衍生物、噻吩及其衍生物的乙酰化反应时电呈现较好的催化活性和选择性,其中,2-乙酰噻吩的收率和选择性分别达到86.93%和99%以上。

Application of Transition Metal-Modified Phosphotungstate Catalysts in Friedel-Crafts Acet3rlation

A series of transition metal-modified phosphotungstate catalysts(M_xH_(3-2x)PW_(12)O_(40),M= Co,Cu,Zn,Ni)were prepared and characterized by means of BET,ICP,XRD,FTIR and NH_3-TPD. Activities of the M_xH_(3_2x)PW_(12)O_(40)catalysts in Friedel-Crafts acetylations of aromatic compounds were investigated.The experimental results showed that the porous M_xH_(3-2x)PW_(12)O_(40)catalysts kept the primary Keggin structure and the acid strength of phosphotungstic acid H_3PW_(12)O_(40),but their acid amounts were more than that of H_3PW_(12)O_(40).Compared with H_3PW_(12)O_(40)and Cs_(2.5)H_(0.5)PW_(12)O_(40) catalysts,both activities and selectivities of the M_xH_(3-2x)PW_(12)O_(40)catalysts(except Co_(1.5)PW_(12)O_(40))in acetylation of anisole were high,in which Co_(0.5)H_2PW_(12)O_(40)catalyst was best,and yield and selectivity of product p-methoxyacetophenone(p-MOPA)could be 84.36% and 96.78%,respectively.Both activity and selectivity of the Co_(0.5)H_2PW_(12)O_(40)catalyst were high when it was used in acetylations of benzene derivatives,thiophene and its derivatives.For example,yield and selectivity of 2-acetyl thiophene could reach 86.93% and more than 99%,respectively.