乙酸溶剂中空心钛硅分子筛催化甲苯氧化制甲基苯酚研究
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摘要
以钛硅分子筛(TS-1)经重排扩孔得到的空心钛硅分子筛(HTS)为催化剂、乙酸[36%(w),下同]为溶剂,考察了不同因素对甲苯与双氧水氧化反应制甲基苯酚(甲酚)的影响。结果表明:乙酸对该反应具有明显的促进作用;初期反应主要发生在分子筛的外表面;随着反应的进行,分子筛孔道中反应增加;在优化的反应条件下,甲苯转化率达15.1%,甲酚选择性超过95.0%,对位/邻位产物收率比约为1.28。
Cresol is an important chemical intermediate which is mainly produced through complicated and pollutant traditional methods. While titanium silicalite(TS-1) catalyzed toluene oxidation using hydrogen peroxide as oxidant is a clean route for cresol synthesis. This study investigated the effects of different factors on toluene and hydrogen peroxide reaction,using HTS as catalyst which is recrystalized from TS-1 zeolite and acetic acid[36%(w)]as solvent. The results showed that acetic acid[36%(w)] was effective for promoting the reaction. The oxidation occurred mainly at the outside of the zeolite in early reaction stage,while more reaction was taken place inside the channels of the zeolite as the reaction proceeds. Under optimized conditions,the toluene conversion rate,the selectivity of cresol and the molar ratio of para-cresol/ortho-cresol of cresol product reached to 15.1%,95.0%,1.28,respectively.
Cresol is an important chemical intermediate which is mainly produced through complicated and pollutant traditional methods. While titanium silicalite(TS-1) catalyzed toluene oxidation using hydrogen peroxide as oxidant is a clean route for cresol synthesis. This study investigated the effects of different factors on toluene and hydrogen peroxide reaction,using HTS as catalyst which is recrystalized from TS-1 zeolite and acetic acid[36%(w)]as solvent. The results showed that acetic acid[36%(w)] was effective for promoting the reaction. The oxidation occurred mainly at the outside of the zeolite in early reaction stage,while more reaction was taken place inside the channels of the zeolite as the reaction proceeds. Under optimized conditions,the toluene conversion rate,the selectivity of cresol and the molar ratio of para-cresol/ortho-cresol of cresol product reached to 15.1%,95.0%,1.28,respectively.
引文
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[3] Shinohara Y,Isaka T.Process for preparation of cresol and acetone from cymene hydroperoxide:The United States,US 3720716[P].1973-03-13
[4] Weber M,Weber M.Phenolic Resins:A Century of Progress[M].Heidelberg:Springer-Verlag Berlin Heidelberg,2010:9-23
[5] Taramasso M,Perego G,Notari B.Preparation of porous crystalline synthetic material comprised of silicon and titanium oxides:The United States,US 4410501[P].1983-10-18
[6] Esposito A,Taramasso M,Neri C.Hydroxylating aromatic hydrocarbons:The United States,US 4396783[P].1983-08-02
[7] Mukherjee P,Bhaumik A,Kumar R.Eco-friendly,selective hydroxylation of C7 aromatic compounds catalyzed by TS-1/H2O2 system under solvent-free solid-liquid-liquid-type triphase conditions[J].Industrial & Engineering Chemistry Research,2007,46(25):8657-8664
[8] Sakullimcharoen S,Manit P,Mongkhonsi T.Catalytic activity of TS-1 on the hydroxylation of benzene and toluene with hydrogen peroxide in a bubble reactor[J].Chiang Mai Journal of Science,2008,35(1):163-170
[9] Boccuti M R,Rao K M,Zecchina A,et al.Spectroscopic characterization of silicalite and titanium-silicalite[J].Studies in Surface Science and Catalysis,1989,48:133-144
[10] Bordiga S,Boscherini F,Coluccia S,et al.EXAFS study of Ti-Silicalite:Structure of framework Ti (Ⅳ) in presence and in absence of reactive molecules (H2O,NH3)[J].Catalysis Letters,1994,26(1/2):195-208
[11] Zecchina A,Bordiga S,Lamberti C,et al.Structural characterization of Ti centres in Ti-silicalite and reaction mechanisms in cyclohexanone ammoximation[J].Catalysis Today,1996,32(1):97-106
[12] Clerici M G,Ingallina P.Epoxidation of lower olefins with hydrogen peroxide and titanium silicalite[J].Journal of Catalysis,1993,140(1):71-83
[13] Kumar R,Mukherjee P,Bhaumik A.Enhancement in the reaction rates in the hydroxylation of aromatics over TS-1/H2O2 under solvent-free triphase conditions[J].Catalysis Today,1999,49(1/2/3):185-191
[2] Weissermel K,Arpe H J.Industrial Organic Chemistry[M].4th Ed.Weinheim:Wiley-VCH Verlag Gmb H & Co.,2003:362-363
[3] Shinohara Y,Isaka T.Process for preparation of cresol and acetone from cymene hydroperoxide:The United States,US 3720716[P].1973-03-13
[4] Weber M,Weber M.Phenolic Resins:A Century of Progress[M].Heidelberg:Springer-Verlag Berlin Heidelberg,2010:9-23
[5] Taramasso M,Perego G,Notari B.Preparation of porous crystalline synthetic material comprised of silicon and titanium oxides:The United States,US 4410501[P].1983-10-18
[6] Esposito A,Taramasso M,Neri C.Hydroxylating aromatic hydrocarbons:The United States,US 4396783[P].1983-08-02
[7] Mukherjee P,Bhaumik A,Kumar R.Eco-friendly,selective hydroxylation of C7 aromatic compounds catalyzed by TS-1/H2O2 system under solvent-free solid-liquid-liquid-type triphase conditions[J].Industrial & Engineering Chemistry Research,2007,46(25):8657-8664
[8] Sakullimcharoen S,Manit P,Mongkhonsi T.Catalytic activity of TS-1 on the hydroxylation of benzene and toluene with hydrogen peroxide in a bubble reactor[J].Chiang Mai Journal of Science,2008,35(1):163-170
[9] Boccuti M R,Rao K M,Zecchina A,et al.Spectroscopic characterization of silicalite and titanium-silicalite[J].Studies in Surface Science and Catalysis,1989,48:133-144
[10] Bordiga S,Boscherini F,Coluccia S,et al.EXAFS study of Ti-Silicalite:Structure of framework Ti (Ⅳ) in presence and in absence of reactive molecules (H2O,NH3)[J].Catalysis Letters,1994,26(1/2):195-208
[11] Zecchina A,Bordiga S,Lamberti C,et al.Structural characterization of Ti centres in Ti-silicalite and reaction mechanisms in cyclohexanone ammoximation[J].Catalysis Today,1996,32(1):97-106
[12] Clerici M G,Ingallina P.Epoxidation of lower olefins with hydrogen peroxide and titanium silicalite[J].Journal of Catalysis,1993,140(1):71-83
[13] Kumar R,Mukherjee P,Bhaumik A.Enhancement in the reaction rates in the hydroxylation of aromatics over TS-1/H2O2 under solvent-free triphase conditions[J].Catalysis Today,1999,49(1/2/3):185-191