The carbonylation of phenyl bromide catalyzed by Co（OAc）_2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive.With strong base CH_3ONa,PhCOOCH_3 is produced in 70...The carbonylation of phenyl bromide catalyzed by Co（OAc）_2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive.With strong base CH_3ONa,PhCOOCH_3 is produced in 70%yield with 100%selectivity,the similar results are also obtained with a stronger base（CH_3）_3CONa.However,with another strong base NaOH,the yield of the ester is only 40%.On the other hand,with weak base NaOAc or（n-C_4H_9）_3N,phenyl bromide cannot be carbonylated.The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o,m,p-BrC_6H_4CH_3 are similar to phenyl bromide, while the activities of o,m,p-BrC_6H_4Cl are higher with the high yields（≥93%） of the corresponding chloro-esters.In addition,the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation.展开更多
Transition metal M(M=Mn,Fe,Co,Ni,Cu,and Zn)doped mesoporous titania with a crystalline framework was employed as catalysts for the oxidation of p-bromotoluene(PBT)to p-bromobenzaldehyde(BBD)in acetic acid using aqueou...Transition metal M(M=Mn,Fe,Co,Ni,Cu,and Zn)doped mesoporous titania with a crystalline framework was employed as catalysts for the oxidation of p-bromotoluene(PBT)to p-bromobenzaldehyde(BBD)in acetic acid using aqueous hydrogen peroxide as oxidant.It was found that mesoporous TiO_(2) doped with those metals(Fe,Co and Ni)whose atomic radii are relatively smaller exhibited higher conversion rate of PBT.Among these catalysts,the Co/meso-TiO_(2) exhibited high substrate conversion and good product(p-bromobenzaldehyde)selectivity plus it can be reused once with almost the same activity.The effect of different Ti/Co(molar)ratio on the activities of Co/meso-TiO_(2) was also investigated.展开更多
综合分析沙坦联苯的各种合成工艺的利弊之后,确定以对溴甲苯和邻氯苯甲腈为原料一步催化合成。并对该工艺的反应配比、催化剂配比、反应温度、滴加速度进行了深入细致的研究,确定摩尔比邻氯苯甲腈:对溴甲苯:N iC l2.6H2O:PPh3:Zn=0.3:0....综合分析沙坦联苯的各种合成工艺的利弊之后,确定以对溴甲苯和邻氯苯甲腈为原料一步催化合成。并对该工艺的反应配比、催化剂配比、反应温度、滴加速度进行了深入细致的研究,确定摩尔比邻氯苯甲腈:对溴甲苯:N iC l2.6H2O:PPh3:Zn=0.3:0.25:0.125:0.5:0.275可得到收率85%、含量99.0%以上产品。展开更多
文摘The carbonylation of phenyl bromide catalyzed by Co（OAc）_2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive.With strong base CH_3ONa,PhCOOCH_3 is produced in 70%yield with 100%selectivity,the similar results are also obtained with a stronger base（CH_3）_3CONa.However,with another strong base NaOH,the yield of the ester is only 40%.On the other hand,with weak base NaOAc or（n-C_4H_9）_3N,phenyl bromide cannot be carbonylated.The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o,m,p-BrC_6H_4CH_3 are similar to phenyl bromide, while the activities of o,m,p-BrC_6H_4Cl are higher with the high yields（≥93%） of the corresponding chloro-esters.In addition,the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation.
基金the National Natural Science Foundation of China(Grants Nos.20463003,20567004)Natural Science Foundation of Yunnan Province(Project 2007B018M)for financial support.
文摘Transition metal M(M=Mn,Fe,Co,Ni,Cu,and Zn)doped mesoporous titania with a crystalline framework was employed as catalysts for the oxidation of p-bromotoluene(PBT)to p-bromobenzaldehyde(BBD)in acetic acid using aqueous hydrogen peroxide as oxidant.It was found that mesoporous TiO_(2) doped with those metals(Fe,Co and Ni)whose atomic radii are relatively smaller exhibited higher conversion rate of PBT.Among these catalysts,the Co/meso-TiO_(2) exhibited high substrate conversion and good product(p-bromobenzaldehyde)selectivity plus it can be reused once with almost the same activity.The effect of different Ti/Co(molar)ratio on the activities of Co/meso-TiO_(2) was also investigated.
文摘综合分析沙坦联苯的各种合成工艺的利弊之后,确定以对溴甲苯和邻氯苯甲腈为原料一步催化合成。并对该工艺的反应配比、催化剂配比、反应温度、滴加速度进行了深入细致的研究,确定摩尔比邻氯苯甲腈:对溴甲苯:N iC l2.6H2O:PPh3:Zn=0.3:0.25:0.125:0.5:0.275可得到收率85%、含量99.0%以上产品。
