Cycling of waste fusel alcohols from sugar cane industries using supercritical carbon dioxide

Abstract

The present study describes the clean synthesis of non-phosgene organic carbonates (NPOCs) from a selective multicomponent reaction with two important by-products from sugar and alcohol industries, namely, fusel alcohols and carbon dioxide, in the presence of 1,8-diazabicycloundecene (DBU), 1,5-diazabicyclo[4.3.0]-non-5-ene (DBN) or 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]-pyrimidine (TBD) and an alkylating agent. The bases were used for the nucleophilic activation of the alcohols. The synthesis of carbonates was carried out without solvent and confirmed by GC-MS with EI ionization mode, 1 H-and 13 C-NMR and FT-IR analysis. The carbonates were obtained in excellent yields. Crude fusel alcohol can be converted to alkylcarbonates. The proposed methodology can also be employed to convert other hydroxylated compounds into carbonates.

One‐Pot Synthesis of Organic Carbonate from Alcohol and Alkyl Bromide under Low CO2 Pressure

“…Plausible reaction mechanism . According to the previous reports, [35–38] as well as the experimental results obtained in this study, a plausible reaction mechanism has been proposed (Scheme 4). DBU can produce an unstable amidinium alkyl carbonate intermediate I [DBUH] + [R 1 OCOO] − by reacting with CO 2 and alcohol [29,41–43] .…”

“…In the 1990s, McGhee et al [35,36] developed organic superbases-promoted synthesis of organic carbamate or carbonate from CO 2 and amine or alcohol. Pereira et al [37] reported the synthesis of organic carbonates from fusel alcohols and CO 2 in the presence of DBU and an alkylating agent. Shang et al [38] reported the guanidine-promoted direct synthesis of open-chained carbonates.…”

“…developed organic superbases‐promoted synthesis of organic carbamate or carbonate from CO 2 and amine or alcohol. Pereira et al [37] . reported the synthesis of organic carbonates from fusel alcohols and CO 2 in the presence of DBU and an alkylating agent.…”

Solubility of hydrocarbon oils in alcohols (≤C6) and synthesis of difusel carbonate for degreasing

“…[35][36][37] Carbonate esters of isoamyl alcohol have been previously prepared such as its reaction in supercritical carbon dioxide with n-butyl bromide and 1,8-diazabicycloundecene as base to form isoamyl n-butyl carbonate. 38 However, dimethyl carbonate (DMC) has become a widely available solvent/reagent that can serve as a synthetic equivalent of carbon dioxide. 39,40 The mixed isoamyl methyl carbonate, for nail polish removal, 41 was made by potassium carbonate catalyzed reaction of isoamyl alcohol with excess DMC.…”

Circular economy design considerations for research and process development in the chemical sciences

“…Particularly appealing is the use of carbon dioxide and its sequestering into the chemical structure of recirculated products. 183 The use of wastes and recycled materials might be an uncomfortable concept for research chemists who deal with pure, refined chemical intermediates, but this position is being eroded away with time as innovative examples begin to appear in the literature, 184 especially in materials science. 185 The opinion of industry is quite different, with companies increasingly looking to supplement the revenue from their traditional (and sometimes declining) business by valorising their waste stream.…”