Preparation Of Ordered Titanium Silicalite-1Film AndApplication For Catalyzing The Reaction Of Cyclohexanone Ammoximation

Titanium silicalite-1(TS-1) is an environmentally benigned catalyst with goodcatalytic performances. The reaction systems catalyzed by TS-1have mild reactioncondition, good reaction efficiency and low environment pollution, which attractedresearchers’ much attention.TS-1zeolite film not only inherited the excellent catalyticproperties of TS-1crystals, but also was suitable to fixed bed reactor by immobilizedthe catalyst crystals. Its potential perspective would be wide in microreactor.In this paper, hydrothermal crystallizationand seeded growth methods were usedto synthesize TS-1zeolite film on glass substrate. The prepared zeolite film was thenapplied in the self-made microreactor to evaluate the cyclohexanone ammoximationreaction.In the hydrothermal crystallization method, a highly b-oriented TS-1zeolite filmwas obtained when polyvinyl acetate (PVAc) as an interlayer modified the glasssubstrate. The effect of coating quantity of the PVAc, the precursor volume and otherfactors on the orientation and morphology of TS-1were investigated. The polar groupof C=O on PVAc changed the hydrophilicity of the substrate surface, and benefited toattract the precursor of TS-1by favorable interactions of van der Waals and interfacialtension, and then prompted the precursor distribution, nucleation and growth to form ahighly b-oriented and fully covered TS-1film.Meanwhile, the TS-1film obtained by seeded growth method has goodb-orientation and high survival ability on substrates. The crystallization time andprecursor composition etc. had great influences on molecular sieve membranemorphology.The substrate surfaces were characterized by Fourier transform infraredspectroscopy (FT-IR), Microscopic Raman Spectrometer (Raman) and a contact-angleinstrument. Combined with the obtained experimental results, we proposed afabricating scheme of b-oriented TS-1film. We believed that changing thehydrophilicity of the substrate surface would attract the nutrients to substrate, and theexistence of the polar groups such as C=O, Si-OH would affect the nutrientsdistribution, nucleation and growth to form a highly b-oriented TS-1film.Finally, solvent evaporation deposition method was used to prepare TS-1film, and the as obtained films were applied in the self-made micro-reactor to evaluate thecyclohexanone ammoximation reaction. The results showed that, b-oriented TS-1zeolite films shortened the diffusion distance of the reactants and increased theutilization of the zeolite channel. Compared with the random-oriented TS-1films, theconversion rate of cyclohexanone and cyclohexanone oxime selectivity wereincreased by15%and16%. When the space velocity was10h-1, the suitable catalystload was0.16g, both the conversion and yield were more than95%, which fullymeeted the outcomes of powder catalyst in slurry bed reactor.