AICHE JOURNAL
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2018
·Vol. 65
·期 2
·675-683
·
IF 3.326
Hao Qin,Zhen Song,Qian Zeng,Hongye Cheng,Lifang Chen,Zhiwen Qi
The traditional production of long-chain organic esters like isobutyl isobutyrate (BIBE) suffers from severe problems due to the homogenous catalyst in process and complex system thermodynamics. In this work, an innovative bifunctional deep eutectic solvent (DES) is introduced, playing as both reaction catalyst and extraction solvent, to intensify the esterification process. The DES was formed by imidazole (Im) and p -toluenesulfonic acid (PTSA), which was for the first time found acid–base tunable, represented by weak basic DES [3Im:PTSA] and strong acidic DES [Im:2PTSA]. The formation mechanisms of [3Im:PTSA] and [Im:2PTSA] were illustrated by Fourier-transform infrared spectroscopy (FTIR) and COnductor-like Screening MOdel for Real Solvent (COSMO-RS) combined with the Im-PTSA phase diagram. The dual functions of the acidic [Im:2PTSA] in reactive extraction were evaluated by σ -potential analysis and esterification experiments. The high conversion, easy product separation, and good solvent reusability confirm the excellent catalytic and solvent effect of [Im:2PTSA]. © 2018 American Institute of Chemical Engineers AIChE J , 65: 675–683, 2019
研究领域:
化学工程
·
有机合成
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DOI
高影响因子
Sustainable Energy & Fuels
·
2020
·Vol. 4
·期 4
·2018-2025
·
IF 5.503
Songyan Jia,Jiao Ma,Dongping Wang,Kangjun Wang,Qiang Zheng,Chunshan Song,Xinwen Guo
Levulinic acid (LA) is a promising renewable platform compound derived from biomass for the manufacture of various valuable chemicals, among which levulinate esters have been demonstrated to be good fuel additives. Many previous studies have focused on the production of short-chain levulinates for biofuels such as methyl and ethyl levulinates, but these esters suffer from some essential issues including a high oxygen content, low energy density (or heating value) and water solubility. Long-chain levulinate esters have similar structures to biodiesel. The long carbon chain may provide a higher carbon content and strong hydrophobicity, therefore improving the energy density and water insolubility. In this work, the synthesis of a long-chain levulinate ester, n-hexyl levulinate (HL), has been fast and efficiently achieved by the catalytic esterification of LA and 1-hexanol at low temperature. Tungsten hexachloride (WCl6) showed the most superior activity among the tested metal salt catalysts under mild conditions. A HL yield of ∼85% with almost complete LA conversion could be obtained at 50 °C after only 30 min. Other hexanols that have larger steric hindrances, such as 2-ethyl-1-butanol, 2-hexanol, 3-hexanol and cyclohexanol, could also promote efficient esterification with LA over the WCl6 catalyst, resulting in excellent product yields of ∼82–91%. The strategy applies to the efficient synthesis of longer chain levulinate esters such as n-octyl levulinate (OL) as well. The WCl6 catalyst was reusable several times in a consecutive batch reaction mode. The method reported herein offers a strategy for the efficient production of liquid fuels from LA, potentially bridging raw biomass feedstocks and terminal utilization of biobased products.
研究领域:
化学工程
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2020
·
IF 2.627
Yishan Zhou,Hao Qin,Hongye Cheng,Lifang Chen,Bingjian Zhang,Zhiwen Qi
Butyl hexanoate (BuHE) is an important long-chain ester that is widely used in the food, beverage and cosmetic industries. In this work, reactive extraction concept was proposed to intensify the BuHE formation in a biphasic system, in which deep eutectic solvent (DES) comprising 2-methylimidazole (2-MIm) and p -toluenesulfonic acid (PTSA) was used as dual solvent-catalyst. First, the effect of 2-MIm to PTSA molar ratio on esterification was investigated to determine the optimum DES of [2-MIm:2PTSA], which was characterized by FT-IR and TGA. Then, the liquid–liquid equilibrium (LLE) and esterification experiments were carried out to confirm the extraction and catalytic effect of [2-MIm:2PTSA], respectively. Afterwards, the pseudo-homogeneous kinetic model was employed to describe the esterification kinetics. Finally, the intensification mechanism of reactive extraction for BuHE formation was proposed according to the experiments and interaction effect analysis.
研究领域:
化学工程
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
PHARMACEUTICAL RESEARCH
·
2014
·Vol. 31
·期 8
·1907-1918
·
IF 3.952
Chen Yang,Cun Dongmei,Quan Peng,Liu Xiaochang,Guo Wenjia,Peng Lihua,Fang Liang
Purpose Saturated long-chain esters of isopulegol were synthesized and their activities as permeation enhancers for transdermal delivery of amlodipine and flurbiprofen were investigated, in contrast to the saturated fatty acids and isopulegol, as well as their physical mixtures. Methods
In vitro permeation experiments, confocal laser scanning microscopy (CLSM) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were introduced to investigate the regulation of enhancers in the skin permeability and biophysical properties. With in vitro cytotoxicity test and in vivo erythema model, the skin irritation of enhancers was evaluated. Results The esters significantly increased the permeation of amlodipine and flurbiprofen, whereas saturated fatty acids and isopulegol had no such effect and even decreased the drug permeation when they were used alone or in combination. These results were supported by CLSM and ATR-FTIR studies, which revealed that only the esters could decrease the order of the alkyl chains in the skin lipids. Additionally, almost no skin irritation and cytotoxicity were observed for these esters. Conclusions Saturated long-chain esters of isopulegol are shown to be suitable permeation enhancers for transdermal drug delivery. Covalent attachment of isopulegol and saturated fatty acids might represent a promising strategy to design novel and potent permeation enhancers.
研究领域:
药剂学
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生物医学工程
✓ 已验证
DOI
PubMed
高影响因子
Food Chemistry-X
·
2024
·
IF 6.5
Qiao Huang,Ying Liu,Lei Tian,Fuqiang Xiong,Zongjun He,Yanhui Zhao,Shuangquan Xiang,Xianping Qiu,Jianshen Yu,Tongwei Guan
By examining and analyzing bran-free fermented Baijiu (BFB) with varying storage periods (0–20 years), it was observed that the overall concentration of volatile compounds initially increases and subsequently decreases over time. Furthermore, BFB exhibited more kinds of long chain esters, higher concentration of acetals, and reduced furfural content. The process of cellaring can enhance the aged, sweet, and fruity aroma of BFB. 16 flavor compounds, including 1,1-diethoxyethane, ethyl dodecanoate, and ethyl hexadecanoate, can be used as markers for vintage BFB, and electronic sensory technology was capable of discerning BFB in different years. The results of redundancy analysis (RDA) showed a positive correlation between metals and aldehydes, esters, and ketones, while indicating a negative correlation with acids and alcohols. Al, Fe, and Ca underwent the most significant changes during storage period, and they were positively correlated with differential substances, such as benzaldehyde, vanillin, ethyl isovalerate, and ethyl palmitate ( P < 0.01).
研究领域:
食品科学
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化学工程
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分析化学
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感官科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）