Preparation of biodiesel from waste oils containing 72% of free fatty acids catalyzed by a novel Br?nsted acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate([BHSO_3MIM][HSO_4]) was systematically invest...Preparation of biodiesel from waste oils containing 72% of free fatty acids catalyzed by a novel Br?nsted acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate([BHSO_3MIM][HSO_4]) was systematically investigated.The optimum molar ratio of methanol to waste oils,catalyst amount,reaction temperature and reaction time were 8/1,10%(based on the mass of waste oils),140°C and 6 h,respectively,under which the obtained yield of biodiesel reached 94.9%.Also,[BHSO_3MIM][HSO_4] as a catalyst still retained around 97% of its original catalytic activity after successive re-use of 5 batches(6 h per batch),showing the excellent operational stability.Moreover,the acidic IL [BHSO_3MIM][HSO_4] was able to ef ficiently catalyze conversions of waste oils with different amounts of FFAs(free fatty acids) into biodiesel,and showed tremendous application potential.Therefore,an ef ficient and environmentally friendly catalyst is provided for the synthesis of biodiesel from waste oils with high acid value.展开更多
To determine the structure of o-methylisourea for instructing its application and factory production, crystalline o-methylisourea hydrosulfate was synthesized in this paper by methylation of urea with dimethylsulfate,...To determine the structure of o-methylisourea for instructing its application and factory production, crystalline o-methylisourea hydrosulfate was synthesized in this paper by methylation of urea with dimethylsulfate, followed by acidification in 53% yield. Its single crystal prepared from 95% ethanol is determined by X-ray diffraction analysis. The crystal is of monoclinic, space group P21/c with a = 8.5330（10）, b = 7.0548（9）, c = 11.6764（14） A°, β = 95.429（2）°, Mr = 172.16, V= 699.75（15）A°^3, Dc = 1.634 g/cm^3, Z = 4, F（000） = 360 andμ（MoKα） = 0.435 mm^-1. Of 1511 unique reflections, 1294 is gotten （I 〉 2σ（I））. The structure was solved by Fourier method and refined to R = 0.0438 and wR = 0.1209. The crystal structure shows that o-methylisourea combines with bisulfate via the intramolecular hydrogen bond between N（2）-H（4） of o-methylisourea and O（2） of bisulfate. As a result, the molecular structure is [H2NC（OCH3）NH2]HSO4 and the formula is C2H8N2O5S or C2H7N2O·HSO4 but not H2NC（OCH3）NH-HSO4 or H2NC（OCH3）NH·0.5H2SO4.展开更多
基金Supported by the National Natural Science Foundation of China(21676104,21336002,21376096)the Open Funding Project of the State Key Laboratory of Bioreactor Engineeringthe Program of State Key Laboratory of Pulp and Paper Engineering(2017ZD05)
文摘Preparation of biodiesel from waste oils containing 72% of free fatty acids catalyzed by a novel Br?nsted acidic ionic liquid 1-sulfobutyl-3-methylimidazolium hydrosulfate([BHSO_3MIM][HSO_4]) was systematically investigated.The optimum molar ratio of methanol to waste oils,catalyst amount,reaction temperature and reaction time were 8/1,10%(based on the mass of waste oils),140°C and 6 h,respectively,under which the obtained yield of biodiesel reached 94.9%.Also,[BHSO_3MIM][HSO_4] as a catalyst still retained around 97% of its original catalytic activity after successive re-use of 5 batches(6 h per batch),showing the excellent operational stability.Moreover,the acidic IL [BHSO_3MIM][HSO_4] was able to ef ficiently catalyze conversions of waste oils with different amounts of FFAs(free fatty acids) into biodiesel,and showed tremendous application potential.Therefore,an ef ficient and environmentally friendly catalyst is provided for the synthesis of biodiesel from waste oils with high acid value.
基金This work was supported by the National Natural Science Foundation of China (Nos. 30171070 and 30371632)
文摘To determine the structure of o-methylisourea for instructing its application and factory production, crystalline o-methylisourea hydrosulfate was synthesized in this paper by methylation of urea with dimethylsulfate, followed by acidification in 53% yield. Its single crystal prepared from 95% ethanol is determined by X-ray diffraction analysis. The crystal is of monoclinic, space group P21/c with a = 8.5330（10）, b = 7.0548（9）, c = 11.6764（14） A°, β = 95.429（2）°, Mr = 172.16, V= 699.75（15）A°^3, Dc = 1.634 g/cm^3, Z = 4, F（000） = 360 andμ（MoKα） = 0.435 mm^-1. Of 1511 unique reflections, 1294 is gotten （I 〉 2σ（I））. The structure was solved by Fourier method and refined to R = 0.0438 and wR = 0.1209. The crystal structure shows that o-methylisourea combines with bisulfate via the intramolecular hydrogen bond between N（2）-H（4） of o-methylisourea and O（2） of bisulfate. As a result, the molecular structure is [H2NC（OCH3）NH2]HSO4 and the formula is C2H8N2O5S or C2H7N2O·HSO4 but not H2NC（OCH3）NH-HSO4 or H2NC（OCH3）NH·0.5H2SO4.
