Research Of Composite Molecular Sieve Catalysis Over Phenol And Isopropanol Alkylation

Alkyl-phenols are the most important fine chemical intermediate. The mainproduct alkylation of phenol and isopropanol is isopropenylphenol, the ortho and paraisomers has a relatively wide range application of used in the chemical industrialproduction. For example, p-isopropylphenol (p-IPP) has been extensively used for cablepackage coatings, machinery cleaner, synthetic resin, interfacial agent, cementingsubstance, medicine intermediate, preservative, fuel dope and so on; o-isopropylphenol(o-IPP) is not only for the above purposes but also as a pesticide intermediates. Atpresent, Isopropylphenol was mainly produced by batch autoclave reaction process,however this process usually gives rise to many problems, such as separation difficulty,erosion, pollution. Zeolite and solid acid as catalyst, using the fixed-bed reactortechnology not only can overcome both separation difficulty, equipment corrosion andpollution problem in the process, but aslo can achieve continuous production.In this paper, we prepared some composite molecular sieves: β-MCM-41,ZSM-5/MCM-41-3d, H-ZSM-5-silicalite-1, at the same time, compare one-componentof Beta zeolite, H-ZSM-5zeolite and mechanical mixing zeolites mixtureBeta-MCM-41, mixture Z-5-MCM-41with composite molecular sieves. The above ofmolecular sieves are selected as novel catalysts for alkylation of phenol withisopropanol. Combined with various characterization means for physical and chemicalproperties of the catalyst is analyzed, the method of experimental study is gas-solidfixed bed reaction. Under different reaction conditions, the catalytic performance ofcatalysts are investigated. The main experimental results and conclusions are list below:1. Synthetic composite molecular sieve samples were characterized by XRD,NH3-TPD, SEM, N2adsorption–desorption. The results showed that synthetic samplesβ-MCM-41, ZSM-5/MCM-41-3d and H-ZSM-5-silicalite-1had several acidic centersand dual structures.2. Using composite molecular sieve β-MCM-41as catalyst for alkylation of phenolwith isopropanol, under the optimal reaction conditions（T=300℃, n(IPA)/n(Phenol)=0.8, LHSV=3h-1, Catalyst Loading=0.3g）, the selective of o-isopropylphenol is22.94%, the selective of p-isopropylphenol is44.44%, the conversion of phenol is79.54%, thetotal yield of the product is53.58%(Yo-IPP%=18.24%，YP-IPP%=35.34%). To compareβ-MCM-41with mechanical mixing zeolites and one-component of Beta zeolites, at thesame reaction conditions, microporous-mesoporous composite zeolite β-MCM-41hasgood structural superiority, more stronger acidity and more amount of acid. β-MCM-41not only shows a higher the conversion of phenol (increased respectively by about26%and11%), and the total product yield has been improved (increased respectively byabout20.17%and12.19%).3. Under optimized reaction conditions: T=300℃, LHSV=3h-1, n(IPA)/n(Phenol)=0.8, Catalyst Loading=0.3g. Using composite molecular sieve ZSM-5/MCM-41-3d ascatalyst for alkylation of phenol with isopropanol, the conversion of phenol is75.16%,the selective of o-isopropylphenol is18.19%, the selective of p-isopropylphenol is60.72%, and the total yield of the product is59.85%(YO-IPP%=14.21%，YP-IPP%=45.64%). Microporous-mesoporous composite zeolite ZSM-5/MCM-41-3d hassuitable acid sites and more amount of acid, in addition, ZSM-5/MCM-41-3d hasabsolute advantage on the structure, so the catalytic properties of composite molecularsieve are much better that compare it with H-ZSM-5zeolite and mixture Z-5-MCM-41.ZSM-5/MCM-41-3d not only shows a higher the conversion of phenol (increasedrespectively by about37%and27%), and the total product yield has been improved(increased respectively by about24.5%å'Œ29.23%).4. The catalyst alkylation of phenol and isopropanol is H-ZSM-5-silicalite-1, theoptimal conditions of reaction is T=300℃, Catalyst Loading=0.3g,n(IPA)/n(Phenol)=0.8, LHSV=3h-1. At above of these conditions, the conversion ofphenol is67.48%, the selective of o-isopropylphenol is7.03%, the selective ofp-isopropylphenol is71.72%, and the total yield of the product is53.13%(YO-IPP%=4.74%，YP-IPP%=48.39%). The experimental results of H-ZSM-5-silicalite-1contrastwith H-ZSM-5zeolite under the above reaction conditions, composite molecular sieveH-ZSM-5-silicalite-1has a good advantage of core-shell structure, suitable acid sitesand more amount of acid, H-ZSM-5-silicalite-1will enhance the conversion ofphenol29.14%and the total product yield about18%.