Microwave assisted catalytic hydrolysis of fibrous cellulose over framework catalysts: effects of acidity and pore struc
- PDF / 1,939,956 Bytes
- 11 Pages / 547.087 x 737.008 pts Page_size
- 10 Downloads / 195 Views
(0123456789().,-volV) ( 01234567 89().,-volV)
ORIGINAL RESEARCH
Microwave assisted catalytic hydrolysis of fibrous cellulose over framework catalysts: effects of acidity and pore structure Songshan Jiang
. Wei Xiong . Bai He . Min Li
Received: 16 July 2020 / Accepted: 1 October 2020 Ó Springer Nature B.V. 2020
Abstract Catalytic hydrolysis of fibrous cellulose (CHFC) over framework catalysts (HY zeolites, SBA15 zeolites and MCM-41) was studied under the microwave (MW) irradiation (MW density of 5 kW/ L) at 200 °C. Results showed that CHFC processes were enhanced by the mesoporous catalysts (cellulose conversion of * 40%, mcatalyst/mcellulose = 1/1) which is 225% higher than the conversion of catalyst-free system. Pore size and structure of the materials play a dominant role on the catalytic hydrolysis of polymer products and acidity plays a secondary role which will further decompose the secondary products, e.g. decomposing glucose and xylose into 5-HMF, furfural and low molecular acids. The catalyst kept high activity after used three times. The MW assisted CHFC mechanism is accounting for the first step decomposition of cellulose over MW system and then further transformation of short-chain cellulose molecules in the mesopores of the catalysts. Keywords Microwave Fibrous cellulose Hydrolysis Framework catalysts
S. Jiang (&) W. Xiong B. He M. Li School of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, China e-mail: [email protected]
Introduction Cellulose and hemicellulose as kinds of biomass are both biopolymers that account for 70–90% of the total mass (Dee and Bell 2011). Cellulose can be mainly decomposed into hexoses which can be used for food or dehydrated into furan-type platform chemicals, HMF (Iris and Tsang 2017) in particular, which is an important precursor to the production of high value polymers such as polyurethanes and polyamides, as well as for biofuels (Roma´n-Leshkov et al. 2007). HMF has retained all six carbon atoms that were present in the hexoses and high selectivity for its preparation from fructose, which compares favourably with other platform chemicals, such as levulinic acid or bioethanol (Van Putten et al. 2013). Technologies for depolymerisation of biomass to chemicals and transportation fuels are intensely investigated (Hassanzadeh et al. 2014; Zhou et al. 2011). Hydrolysis is a useful technology which can transform the cellulose into glucose by breaking the b-1,4 glycosidic bonds under the proton acids or thermal condition in aqueous system (Levi et al. 2016). Literatures reported that H2SO4 (Lin et al. 1992; Liu et al. 2018), HCl (Suzuki et al. 2018), carboxylic acids and p-toluenesulfonic acid (Rinaldi et al. 2008) can be used as catalysts for the hydrolysis of cellulose. Catalytic hydrolysis of cellulose by acids is accounting for the protonic direct attacking b-1,4 glycosidic bonds process which is a two-phase reaction and proton can easily diffuse into
123
Cellulose
macroscopic cellulose. However
Data Loading...
