Abstract
Because H2O decreases the acidity of sulfonic acid-based catalysts and initiates catalytic side reactions, the catalytic activity and selectivity of these catalysts are often unsatisfactory in many reactions that generate H2O as a byproduct. Herein, for the first time, hydrophobic acid-functionalized biochar is prepared by a new route based on a two-step diazo grafting method using 4-aminobenzenesulfonic acid as the sulfonated agent and 4-tert-butylaniline as the hydrophobic agent. The acid density and hydrophobicity can be easily regulated by the amounts of benzenesulfonic acid and tert-butylbenzene groups, respectively. The resulting catalysts have a large specific surface area of 400-700 m2/g, high acid density of greater than 2.0 mmol/g, and strong hydrophobicity with an H2O contact angle of up to 136°. Compared with Amberlyst-15 and H2SO4-sulfonated biochar, the hydrophobic acidic biochar exhibits higher activity and selectivity in the alkylation of 4-ethylphenol with phenylmethanol and of 2-methylfuran with cyclic ketones (cyclopentanone and cyclohexanone) for the production of high-density biofuels. The successful preparation of the hydrophobic acidic biochar not only results in an efficient catalyst for reaction systems in which H2O has a deleterious effect but also paves a way for the functional modification of carbonaceous materials.
Original language | English (US) |
---|---|
Pages (from-to) | 14973-14981 |
Number of pages | 9 |
Journal | ACS Sustainable Chemistry and Engineering |
Volume | 7 |
Issue number | 17 |
DOIs | |
State | Published - Sep 3 2019 |
Keywords
- alkylation
- diazo method
- high-density biofuel
- hydrophobicity
- sulfonic acid-functionalized biochar
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Renewable Energy, Sustainability and the Environment