CATALYSIS LETTERS
·
2024
·
IF 2.3
Shao Yulin,Xie Ping,Han Yuning,Zhong Tianhao,Li Tao,Yu Yingmin,Zhao Qingshan,Li Zhongtao
In response to the problem that the conventional concentrated sulfuric acid catalyst for esterification reactions are prone to corrosion and generate large amounts of acid-containing wastewater, highly efficient gel resin-loaded ionic liquid solid acid (SA-ILs) catalysts were prepared by a one-pot method of loading ionic liquids onto gel resins. It is shown that the gel resin carrier has a strong water-absorbing structure, and the ionic liquids are covalently loaded on the gel resin carrier through chemical bonding, leading to SA-ILs catalysts with excellent acidity and good structural stability. With an optimal ionic liquid loading of 11% and acid density of 3.25 mmol·g −1 ,the synthesized SA-ILs catalysts showed good catalytic performance in the transesterification reaction between acetic acid and ethanol at 80 °C for 1.5 h. The catalyst dosage was 10 wt% of the total mass of acetic acid and ethanol, and the ethanol to acetic acid addition was at a molar ratio of 1.5:1. Ethyl acetate yields of up to 81% were achieved after the reaction. The catalyst also showed slightly decrease of the catalytic performance after reused for five cycles. The lower activation energy of the catalyst is proved to be the key to facilitate the catalytic transesterification reaction. Graphical Abstract
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Kun Li,Baoshan Tang,Wenwen Zhang,Zhengjun Shi,Xinghao Tu,Kai Li,Juan Xu,Jinju Ma,Lanxiang Liu,Hong Zhang
Bleached shellac, a widely used material in food processing and products, was deeply affected in terms of structures and properties by the bleaching method. In the present study, a marked difference was observed between the damage performances of sodium hypochlorite-bleached shellac (SHBS) and hydrogen peroxide-bleached shellac (HPBS). The main bleaching damage reactions of sodium hypochlorite were the addition of double bonds to generate chlorine and the oxidation of hydroxyl to form aldehydes or ketones. In the case of hydrogen peroxide, degradation of shellac resin was caused by the hydrolysis of ester bonds and the oxidation of hydroxyl groups to form aldehydes and ketones, as well as carboxylic acids with deep oxidation. Based on the structural characterization of shellac resin, the bleaching damages were affected by the bleaching agent via the oxidizable groups, such as the unsaturated double bonds, hydroxyl and aldehyde groups in cyclic terpenes, and fatty acid chains. The differences could be attributed to the action of sodium hypochlorite on the hydroxyl group of aldehyde or ketone. Conversely, hydrogen peroxide bleaching oxidized the hydroxyl group and aldehyde group to carboxylic acid and initiated the hydrolysis reaction of the ester bond of the shellac resin, leading to the degradation of the resin. Thus, understanding the mechanism underlying the bleaching damage could provide a scientific basis for the subsequent targeted regulation of bleaching damage.
研究领域:
化学
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材料科学
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DOI
PubMed
高影响因子
Gels
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2025
·Vol. 11
·期 5
·310
·
IF 5.3
Tao Wang,Weian Huang,Jinzhi Zhu,Chengli Li,Guochuan Qin,Haiying Lu
Lost circulation has become one of the important problems restricting the speed and efficiency of oil and gas drilling and production. To address severe drilling fluid losses in high-temperature fractured formations during deep/ultra-deep well drilling, this study developed a high-temperature and high-strength gelled resin gel plugging system through optimized resin matrix selection, latent curing agent, flow regulator, filling material, etc. Comparative analysis of five thermosetting resins revealed urea-formaldehyde resin as the optimal matrix, demonstrating complete curing at 100–140 °C with a compressive strength of 9.3 MPa. An organosilicon crosslsinker-enabled water-soluble urea-formaldehyde resin achieved controlled solubility and flow–cure balance under elevated temperatures. Orthogonal experiments identified that a 10% latent curing agent increased compressive strength to 6.26 MPa while precisely regulating curing time to 2–2.5 h. Incorporating 0.5% rheological modifier imparted shear-thinning and static-thickening behaviors, synergizing pumpability with formation retention. The optimal formula (25% urea-formaldehyde resin, 10% latent curing agent, 10% high-fluid-loss filler, 0.5% rheological modifier) exhibited superior thermal stability (initial decomposition temperature 241 °C) and mechanical integrity (bearing pressure 13.95 MPa in 7 mm wedge-shaped fractures at 140 °C). Microstructural characterization confirmed interlocking crystalline layers through ether-bond crosslinking, providing critical insights for high-temperature wellbore stabilization.
研究领域:
石油工程
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材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2020
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IF 3.209
Xinhui Wang,Rui Li,Xiangyue Liu,Shan Huang,Bin Li,Honglei Wang,Xin Chai,Yuefei Wang
Garcinia kola seeds play an important role in African traditional medicine, which are widely used to treat stomachache, gastritis, malaria, venereal diseases and laryngitis. The habitats, specification, different parts of seeds and slicing process are important factors that affect the quality of Garcinia kola seeds. Interestingly, brownish yellow or brownish red spots were derived from gum resin exuded during slicing, whose chemical constituents have not been elucidated. A rapid high performance liquid chromatography method was established for quantitative study of four main biflavanones (GB-2, GB-1, kolaflavanone and GB-1a) in Garcinia kola seeds. We found that the content of the tested biflavanones was slightly different in Garcinia kola seeds from different habitats, while the seeds weight showed no obvious influence on the biflavanones content from the same habitat. With the aid of “spider-web” mode, we unveiled that the accumulation of biflavanones mainly occurred in seed kernels. Furthermore, slices thickness (1–2 mm) was optimized by comprehensive evaluation of biflavanones’ content, moisture, cutting-time and drying-time to efficiently dry the slices. By employing of ultra-high performance liquid chromatography coupled with electrospray ionization quadrupole Orbitrap high resolution mass spectrometry (UHPLC/ESI Q-Orbitrap MS), garcinoic acid and its derivatives were successfully identified in gum resin, conducing to the interesting finding about the distribution of biflavanones and derivatives of garcinoic acid in Garcinia kola seeds. Generally, our findings in this research could contribute to standardizing the process of harvesting, processing and quality control for Garcinia kola seeds, and help better development and utilization of this important medicinal plant.
研究领域:
药用植物学
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分析化学
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传统医学
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植物科学
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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）