CAJ | 학술논문

以室温沉淀法制备了一系列铵取代磷钨杂多酸盐催化剂（ NH4） x H3－x PW12 O40（ x ＝0．5，1．0，1．5，2．0，2．5，3．0），用X-射线衍射（XRD）、傅里叶-红外光谱（FT-IR）、固体紫外-可见漫反射光谱（DR UV-Vis）、扫描电镜（ SEM）、氮气吸附-脱附（ N2 adsorption-desorption ）等手段对其进行了表征，并考察了它们在H2 O2氧化苯甲醛制苯甲酸反应中的催化活性．结果表明，NH4＋取代H＋后形成的杂多酸盐仍很好地保持了Keggin结构；随着NH4＋取代度的增大，（ NH4） x H3－x PW12 O40的颗粒逐渐均匀，晶格常数逐渐减小，而比表面积和总孔容呈先增大后减小的趋势；在相同实验条件下，所制（NH4）xH3－xPW12O40的催化活性均优于H3PW12O4（71％），其中在（NH4）2．5H0．5PW12O40催化作用下，苯甲酸收率达到最高（76％）．
이실온침정법제비료일계렬안취대린오잡다산염최화제（ NH4） x H3－x PW12 O40（ x ＝0．5，1．0，1．5，2．0，2．5，3．0），용X-사선연사（XRD）、부리협-홍외광보（FT-IR）、고체자외-가견만반사광보（DR UV-Vis）、소묘전경（ SEM）、담기흡부-탈부（ N2 adsorption-desorption ）등수단대기진행료표정，병고찰료타문재H2 O2양화분갑철제분갑산반응중적최화활성．결과표명，NH4＋취대H＋후형성적잡다산염잉흔호지보지료Keggin결구；수착NH4＋취대도적증대，（ NH4） x H3－x PW12 O40적과립축점균균，정격상수축점감소，이비표면적화총공용정선증대후감소적추세；재상동실험조건하，소제（NH4）xH3－xPW12O40적최화활성균우우H3PW12O4（71％），기중재（NH4）2．5H0．5PW12O40최화작용하，분갑산수솔체도최고（76％）．
A series of ammonium salts of 12-tungstophosphoric acid ((NH4)xH3-xPW12O40, x =0.5, 1.0, 1.5, 2.0, 2.5, 3.0) were synthesized by the precipitation method at room temperature .The resulting materials were characterized by XRD, FT-IR, DR UV-Vis, SEM, and N2 adsorption-desorption.Their catalytic activities in the green synthesis of benzoic acid were evaluated under organic solvent-free conditions .The results suggested that the substitu-tion of H +by NH4 +did not change the Keggin structure of H 3 PW12 O40 .On the other hand , the particles became more uniform and the lattice constant decreased with the increase of x in (NH4)xH3-xPW12O40.Meanwhile, the specific surface area and pore volume increased to some extent and ( NH4 )2.5 H0.5 PW12 O40 exhibited the maximum values .It was interesting that ( NH4 ) x H3-x PW12 O40 showed higher catalytic activities than that of bulk H 3 PW12 O40 (71%) , and the yield of benzoic acid may reach up to 76%over (NH4)2.5H0.5PW12O40.