Fabrication of Microspheres by Nano-TS-1 Crystals via a Spray-Forming Process: From Screening to Scale-up

Abstract

The spray-forming process of the nano-titanium silicalite (TS-1) zeolite was investigated and optimized in the lab in order to obtain materials with microsphere morphology and superior catalytic activity in cyclohexanone ammoximation on the industrial scale. The effects of spray-forming parameters, such as the state of the TS-1 raw material, load ratio, solid content, binder content, and calcination temperature, on the physicochemical and catalytic properties of TS-1 microspheres were investigated in detail. It was interesting to find that the shape of the spray-forming sample formed by wet powders was more intact than the sample formed by dried powders. Furthermore, the spray-forming process was successfully scaled up to a large spray device (LGZ-1000) according to the similarity principle of load ratio, and the shape of the TS-1 microspheres was as perfect as the spray-forming samples in the lab. The similarity principle of the load ratio for the spray-forming of titanium silicate was established and verified for the first time. The spray-forming TS-1 microspheres produced in the industry were used in cyclohexanone ammoximation, and ketone conversion and oxime selectivity were as high as 99.9 and 99.4%, respectively.

Hybrid chemoenzymatic heterogeneous catalyst prepared in one step from zeolite nanocrystals and enzyme–polyelectrolyte complexes

“…[39][40][41][42][43][44][45][46][47] In fact, aerosol methods were already demonstrated to be successful and scalable to form TS-1 microspheres with a hierarchical porosity. 48 On the second hand, spray drying is also widely used to dry proteins for food and pharmaceutical applications. [49][50][51][52] However, in the case of enzymes, spray drying oen leads to denaturation, due to the relatively harsh conditions applied during drying (high temperature, liquid/air interfacial stress, shear stress).…”

Hollow zeolite microspheres as a nest for enzymes: a new route to hybrid heterogeneous catalysts

“…The presented aerosol method allows preparing hierarchical hollow zeolite structures using an easy, continuous, and scalable aerosol process. 53 The spheres can be loaded with the enzymes which are then crosslinked 54,55 to secure their entrapment and avoid their subsequent leaching. 56,57 Thus, the hollow microspheres are used both as epoxidation catalysts and as vessels for the enzyme.…”

Synthesis of Low Cost Titanium Silicalite-1 Zeolite for Highly Efficient Propylene Epoxidation

“…Since the titanium silicalite-1 (TS-1) zeolite reported by Taramasso et al (1983) , it has been widely used in many green oxidation reactions with hydrogen peroxide as oxidant owing to its unique catalytic performance in alcohol and alkane oxidation ( Huybrechts et al, 1990 ; Fan et al, 2008 ; Liu et al, 2017 ), aromatic hydroxylation ( Han et al, 2018 ), ketone ammoximation ( Hu et al, 2018 ; Wang et al, 2018 ; Niu et al, 2019 ), oxidative desulfurization ( Bai et al, 2018 ; Du et al, 2019 ) and alkene epoxidation ( Feng et al, 2018 ; Harris et al, 2018 ; Zhang et al, 2018 ; Yuan et al, 2020 ). Generally, nanosized TS-1 zeolites (100–200 nm) are prepared using an organic silicon source (tetraethyl orthosilicalite), organometallic titanium source (tetraethyl orthotitanate), and a large amount of a template material (tetrapropylammonium hydroxide, TPAOH) ( Carati et al, 1999 ).…”