INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Bo Wang,Senlin Deng,Yuhang Bian,Guoliang Zhang,Chunshan Li
The aldol condensation of methyl propionate (MP) and formaldehyde (FA) is an environmentally friendly and sustainable route to produce methyl methacrylate (MMA). However, the side reaction is a huge barrier to achieving high selectivity to the target product. To strengthen the regulation of selectivity for the main reaction, a reaction network was established based on the validation and analysis of side reactions in the system through a combination of experimental and computational methods. The thermodynamics was analyzed through the Gibbs free energy (ΔrGTθ) of reactions. On the basis of a rigorous material balance of all components, the sources and reaction equations of 15 products were identified. The multivariate nonlinear model between the yield of different products and reaction conditions was established to predict the yield of each product. The mean relative error of the actual yield and predicted yield was less than 5%. The key influencing condition for the synthesis of MMA was the liquid hourly space velocity (LHSV).
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL PAPERS
·
2023
·Vol. 77
·期 7
·3713-3726
·
IF 2.2
Xue Tao,Wei Yan,Yu Caili,Zhou Zhongqun,Zhang Faai
A series of mesoporous silica (MS) materials, including rod-like and spherical SBA-15, spherical MCM-41, and MCM-48, was successfully synthesized and modified by silane coupling agent γ-aminopropyltriethoxysilane. The modified MS was utilized as a microreactor for solution reversible addition–fragmentation transfer (RAFT) polymerization of methyl methacrylate (MMA) using xanthate as a chain transfer agent and azodiisobutyronitrile as an initiator. Notably, modified MS had a low specific surface area and pore volume while maintaining the original morphological structure. Given to the confinement effects, poly(methyl methacrylate) (PMMA) prepared from internal mesoporous channels had higher molecular weight and initial thermal decomposition temperature than those from conventional RAFT polymerization. Moreover, PMMA obtained from spherical SBA-15 and modified MCM-48 exhibited the highest molecular weight ( M n = 8.78 × 10 4 and M n = 7.43 × 10 4 , respectively). This work provided a novel approach in designing a polymer microstructure for a more comprehensive application, such as in drug release. Graphical abstract
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER SCIENCE SERIES B
·
2023
·Vol. 65
·期 4
·409-418
·
IF 1.2
Shoucun Zhang,Wang Shengyan,Bian Yujing,Fang Guoli
Abstract Carbon dioxide is a well-known green solvent, and can be used instead of some organic solvent to prepare the polymer products. On the basis of its poor solubility, dispersion polymerization can be adopted to produce the polymer products in industry. Thus, low price, easily available stabilizers with good stabilization effect will be a must. In this paper, we are committed to designing and synthesizing stabilizers with these characteristics. Firstly, thiol ethanol is used as the chain-transfer agent to control the copolymerization of vinyl acetate/vinyl propionate, and the homopolymers or copolymers with the hydroxyl group at the chain terminal are obtained. These homopolymers or copolymers are then functionalized to prepare the stabilizers with methacrylate groups. The results indicate that these stabilizers can effectively control the dispersion polymerization of methyl methacrylate in supercritical carbon dioxide. The proportion of structural units in the copolymer and the concentration of stabilizer or initiator obviously affect the conversion percentage of methyl methacrylate and the molecular weight of polymers. The maximum conversion percentage of methyl methacrylate and the molecular weight of poly(methyl methacrylate) can reach 93%, and 56000 Da, respectively. SEM images show that most of the samples are free-flowing powders with a spherical structure.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2023
·
IF 5.1
Leipeng Liu,Haochen Yun,Jie Xiong,Jiangtao Wang,Zhicheng Zhang
Polymer dielectrics with good energy storage properties are need for advanced electric devices. Herein, a new class of all organic dielectric cross-linkable polymers, poly(methyl methacrylate-glycidyl methacrylate) (P(MMA-GMA)) prepared by radical polymerization , is reported. A comprehensive investigation was conducted to examine the impact of the cross-linked monomer GMA content on the energy storage properties. The crosslinking significantly enhances the breakdown strength and suppresses the leakage currents . Consequently, the copolymer P(MMA-GMA) containing 7 mol% GMA exhibits a high discharge energy density of 16.5 J/cm 3 at 750 MV/m, coupled with a high discharge efficiency of 82%. Even at an elevated temperature of 100 °C, it still possesses a good energy performance of a discharge energy density of 12.1 J/cm 3 and a relatively high efficiency of 80.1% at 650 MV/m. This study offers a simple and effective approach to fabricating all-organic polymer dielectrics with good energy storage properties.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 133
·期 35
·
IF 1.866
Jin Liu,Xiaohui Tian,Jinyu Sun,Yizhong Yuan
Poly(methyl methacrylate- co -butyl methacrylate) [P(MMA- co -BMA)] nanoparticles were synthesized via emulsion polymerization, and incorporated into natural rubber (NR) by latex compounding. Monodispersed, core-shell P(MMA- co -BMA)/casein nanoparticles (abbreviated as PMBMA-CA) were produced with casein (CA) as surfactant. The chemical structure of P(MMA- co -BMA) copolymers were confirmed by 1 H-NMR and FTIR analyses. Transmission electron microscopy demonstrated the core–shell structure of PMBMA-CA, and PMBMA-CA homogenously distributed around NR particles, indicating the interaction between PMBMA-CA and NR. As a result, the tensile strength and modulus of NR/PMBMA-CA films were significantly enhanced. The tensile strength was increased by 100% with 10% copolymer addition, when the molar ratio of MMA:BMA was 8:2. In addition, scanning electron microscopy and atomic force microscopy results presented that the NR/PMBMA-CA films exhibited smooth surfaces with low roughness, and PMBMA-CA was compatible with NR. FTIR-ATR analyses also suggested fewer PMBMA-CA nanoparticles migrated out of NR. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43843.
研究领域:
材料科学
·
高分子化学
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Jun Ren,Xianfeng Wang,Dongfeng Li,Ningxu Han,Biqin Dong,Feng Xing
The brittleness of microcapsule shell greatly restricts its self-healing performance since it is easily ruptured during the mixing process. Based on the heat releasing nature during cement hydration , a novel concept of temperature-adaptive microcapsule (TAM) was proposed, which can exhibit a switchable mechanical property with temperature. In this paper, a series of TAM with polymethylmethacrylate-methacrylate shell and magnesium oxide core was prepared with four designed transition temperature, and were characterised by Fourier transform infrared spectroscopy, nano-indentation tests, scanning electron microscopy, thermalgravity analysis and particle size analysis , which confirmed the success in preparing the TAM. Moreover, the performance of proposed microcapsules in cement was investigated by determining the breakage rate of microcapsule and recovery rate of cement paste under different mixing temperature. The results illustrated that compared to lower mixing temperature, a 75% reduction in breakage rate and a 5% increment in recovery rate was observed in TAM embedded cementitious paste at an elevated mixing temperature. This work should provide a promising approach to improve the performance of microcapsules for self-healing cementitious materials .
研究领域:
材料科学
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
CHIRALITY
·
2024
·Vol. 36
·期 2
·e23643
·
IF 2.8
Xiaojun Li,Qi Li,Liying Yang,Liqin Huang,Chenchen Peng,Jianyong Zheng
In this study, lipase-catalyzed resolution of N-acetyl-DL-methionine methyl ester (N-Ac-DL-MetOMe) was evaluated. A lipase from Brucella thiophenivorans was prone to exhibit high activity and excellent enantioselectivity toward N-Ac-DL-MetOMe to produce the key chiral intermediate N-acetyl-L-methionine methyl ester (N-Ac-L-MetOMe). The results showed that the enzymatic reaction was carried out in 100 g/L racemic substrate for 2 h, the conversion reached 51.3%, the enantiomeric excess value N-Ac-L-MetOMe exceeded 99%, and the enantiomeric ratio value >200. Therefore, the lipase from B. thiophenivorans has potential prospects for the resolution of N-Ac-DL-MetOMe to produce the important intermediate N-Ac-L-MetOMe.
研究领域:
生物催化
·
酶工程
·
有机化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2015
·Vol. 132
·期 32
·
IF 1.768
Li-chao Liu,Mang Lu,Zhao-Hui Hou,Guo-Xiang Wang,Chang-An Yang,En-Xiang Liang,Hu Wu,Xian-Lei Li,Yi-Xue Xu
Photo-induced atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was achieved in poly(ethylene glycol)-400 with nanosized α-Fe 2 O 3 as photoinitiator. Well-defined poly(methyl methacrylate) (PMMA) was synthesized in conjunction with ethyl 2-bromoisobutyrate (EBiB) as ATRP initiator and FeCl 3 ·6H 2 O/Triphenylphosphine (PPh 3 ) as complex catalyst. The photo-induced polymerization of MMA proceeded in a controlled/living fashion. The polymerization followed first-order kinetics. The obtained PMMA had moderately controlled number-average molecular weights in accordance with the theoretical number-average molecular weights, as well as narrow molecular weight distributions ( M w / M n ). In addition, the polymerization could be well controlled by periodic light-on–off processes. The resulting PMMA was characterized by 1 H nuclear magnetic resonance and gel permeation chromatography. The brominated PMMA was used further as macroinitiator in the chain-extension with MMA to verify the living nature of photo-induced ATRP of MMA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42389.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Eco-Environment & Health
·
2025
·Vol. 4
·期 2
·100139
·
IF 17.6
Minghao Zhang,Yijin Lu,Zhuo Wang,Xiong Gao,Xuanhang Luo,Xin Shen,Weixiang Wu,Qingqing Mei
Ionic liquid-catalyzed methanolysis emerges as an efficient technique for transforming PET into premium-grade dimethyl terephthalate (DMT). However, incomplete depolymerization remains a major obstacle to the further industrial application of IL-catalyzed PET methanolysis. The proposed method utilized dimethyl carbonate (DMC) as the solvent for the complete methanolysis of waste PET under mild conditions, resulting in pure DMT and ethylene carbonate (EC) within 2.5 h. The use of 1-ethyl-3-methylimidazolium acetate ([EMIm][OAc]) as the IL catalyst significantly enhanced the reaction efficiency. Spectroscopic analyses using 1 H NMR and FT-IR confirmed the pivotal role of [EMIm][OAc] in establishing multiple hydrogen bonds with the reactants (PET, DMC, and MeOH) and the intermediate [ethylene glycol (EG)] during the catalytic process. This catalytic system exhibited remarkable performance, achieving complete conversion of PET, which resulted in the production of DMT and EC with yields of 99% and 91%, respectively. Moreover, this versatile approach is applicable to the upcycling of a wide variety of commercial polyesters and polycarbonates, underscoring its potential as a comprehensive solution for plastic waste management.
研究领域:
应用化学
·
高分子科学
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2013
·Vol. 20
·期 7
·1-11
·
IF 2.019
Cheng Chuanjie,Bai Xiongxiong,Liu Shaojin,Huang Qinghua,Tu Yuanming,Wu Haiming,Wang Xiaoji
A cardanol-derived reversible addition-fragmentation chain transfer (RAFT) agent was synthesized in 57 % total yield, and a cardanol-based anionic surfactant was also facilely prepared. Emulsion polymerization of methyl methacrylate (MMA) was realized to form a cardanol-terminated PMMA polymer by using the novel RAFT agent as well as the cardanol-based anionic surfactant. To improve the properties of cardanol-terminated PMMA as a material, UV-curing was performed. According to the comprehensive behavior of the UV-cured resins, optimal irradiation time was 20 min.
研究领域:
材料科学
·
高分子化学
·
可持续化学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2020
·Vol. 22
·期 22
·7913-7923
·
IF 9.48
Gang Wang,Zengxi Li,Chunshan Li,Suojiang Zhang
The direct synthesis of methyl acrylate (MA) from methyl acetate and trioxane at 350–380 °C is regarded as a supplementary route for the industrial propylene oxidation process; however, it suffers from rapid catalyst deactivation. Herein, a novel ionic liquid catalyzed mild liquid-phase system was developed for the direct synthesis of MA from methyl acetate and trioxane, where N,O-bis(trimethylsilyl)acetamide (BSA) was used as a probase for α-deprotonation and enol silyl etherification of methyl acetate. The trioxane decomposition to formaldehyde and methyl acetate enolization to 1-methoxy-1-trimethylsilyloxyethene proceeded with the catalysis of [Cation]Cl/MClx (M = Cu+, Fe3+, Zn2+ and Al3+) and [Cation]F, respectively. The cations and anions were observed to have significant effects on the yield and selectivity of MA, owing to the steric hindrance, acid site category and strength confirmed by pyridine probing FT-IR characterization. As a result, up to 60.2% yield with 94.6% selectivity of MA could be achieved when [N3,3,3,3]F and [N3,3,3,3]Cl/AlCl3 with 67 mol% AlCl3 were used in the presence of BSA at 25 °C. Kinetic studies indicated that the trioxane decomposition with the activation barrier of 41.2 ± 0.3 kJ mol−1 was the rate-determining step.
研究领域:
化学工程
·
催化
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DRUG DELIVERY SCIENCE AND TECHNOLOGY
·
2023
·
IF 5
Siyuan Yu,Jinfeng Xing
Erythromycin (EM) was encapsulated into poly(methyl methacrylate) (PMMA) and poly(methyl methacrylate- co - N -vinylcaprolactam) (P(MMA-NVCL)) microspheres in situ by oil-in-water emulsion photopolymerization under green LED irradiation. The physicochemical properties of PMMA-EM and P(MMA-NVCL)-EM microspheres were characterized by SEM, FTIR, TG-DSC and DLS. P(MMA-NVCL)-EM microspheres showed temperature sensitivity, and the EM loading content of PMMA-EM and P(MMA-NVCL)-EM microspheres reached 9.7% and 15.6%, respectively. In vitro release of EM from microspheres presented good controlled release behavior in 12 h. Further release kinetic and thermodynamic investigation revealed that the release process was mainly dominated by EM concentration, accompanied by microspheres relaxation and rupture of hydrogen bonds .
研究领域:
材料科学
·
药学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）