ENERGY & FUELS
·
2020
·
IF 3.421
Yangyang Xin,Yufeng Hu,Mengchen Li,Kebin Chi,Shang Zhang,Fei Gao,Siqi Jiang,Yichuan Wang,Chunxiao Ren,Guohua Li
Alkylation catalyzed by concentrated sulfuric acid (H2SO4) is an important process for industrial production of excellent high octane gasoline blending components. This process has some vital drawbacks such as extensive side reactions and high consumption of H2SO4 due to the presence of the most notorious impurities including H2O, acid soluble oil (ASO), and esters. In this study, isobutane alkylation was studied with H2SO4 (275 mL) in a batch reactor at −10 to 0 °C and 0.45 MPa, with the corresponding stirrer speed, feed rate, acid/hydrocarbon volume ratio, and isobutane/isobutylene volume ratio being 3000 rpm, 5.0 mL/min, 1.2, and 14.3, respectively. The effects of the acid strength and composition of acid on the alkylate quality were investigated. The composition of used acid was analyzed. The results show that used acid is mainly composed of roughly 89% free H2SO4, 6% H2O, 2% esters, and 3% ASO. The compounds existing in the ASO extracted from used acid were identified, and their concentrations were quantitatively determined. The results show that the most abundant ASO molecules are five-membered or six-membered cyclic homoannular conjugated olefins such as cyclopentadiene (15.67%) and cyclohexadiene (14.12%). The effects of acid strength, H2O, ASO, and esters on alkylation depend strongly on the concentrations of H2SO4 and these impurities. Therefore, their optimal concentrations were determined to achieve advantageous effects on the alkylation. The results are about 93–95% for H2SO4, 2–4% for H2O, 1.5–2.5% for ASO, and 0.4–1% for esters, beyond which an adverse effect will appear. Under the optimal concentrations, the value of the research octane number, the trimethylpentane (TMP)/dimethylhexane ratio, and the contents of C8 and TMP remained steady at high levels of about 92–93, 5.8–6.3, 68–70, and 58–60%, respectively.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2014
·
IF 3.32
Qian Han,Xingquan Xiong,Sizhong Li
An efficient, green and scale-up synthesis of amides from esters and amines has been developed using Ru-MACHO as a readily available catalyst. A diverse range of amides were obtained in moderate to excellent yields (55–98%). Furthermore, when the scale of the amidation reaction was increased to 240.0 mmol, the desired amide still could be obtained in high yield (48.2 g of N -benzylbenzamide, 95%).
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
Food Bioscience
·
2020
·
IF 3.067
Liang Gao,Xinyi Cheng,Xuwei Yu,Xiaosan Wang,Qingzhe Jin,Xingguo Wang
1-Oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) is a critical structured lipid in human milk fat and it plays an important role in infants' health. The development of an efficient method for such compound preparation is necessary. In this study, one- and two-step methods for OPL production by enzymatic acidolysis of fractionated palm stearin with mixed acids were compared in solvent-free and solvent systems. The results demonstrated that in the solvent system, the OPL contents by the one- and two-step methods were 45.8% and 56.7%, respectively. In the solvent-free system, the one- and two-step methods resulted in the formation of 43.7% and 54.8% OPL, respectively. Subsequently, acidolysis conditions of the two-step method were optimized. Under the optimum conditions, the content of OPL was 57.7%, and 83.2% of palmitic acid was at the sn-2 position . The prepared OPL has potential to be applied in infant formulas.
研究领域:
食品科学
·
生物化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 130
·107413-107420
·
IF 3.84
Qiwen Yong,Fuwei Nian,Bing Liao,Liping Huang,Lu Wang,Hao Pang
Simultaneously using sulfonic and carboxylic acid as hydrophilic chain-extending agents, a new type of solvent-free and chemical matt waterborne polyurethane resin was prepared and investigated. The chemical structure containing urethane and urea groups in this novel carboxylate/sulfonate type of waterborne polyurethane (CSWPU) resin was confirmed by FTIR, 1H and 13C NMR spectra. An obvious advantage for the environment is that, unlike the traditional synthetic method for waterborne polyurethane, the reactive system doesn't need any organic solvent to reduce the viscosity of the prepolymer in the process of prepolymerization. In addition, the gloss extinction was generated by the drying process of the resin itself, without the requirement of any matting agents. 3D-AFM images indicate that the surface of the matt CSWPU films was extremely rough and was comprised of many spherical particles with diameters in the range of 0.8–3.0 μm arranged on the films' surface. The matt CSWPU resin tended to have a relatively higher molecular weight and lower swelling ratio. Moreover, an increase of sulfonic hydrophilic chain-extending agent content or the initial molecular weight of the soft segment facilitated the improvement of thermal stability.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2017
·Vol. 74
·期 9
·3907-3922
·
IF 1.43
Wei Yanyan,Du Xiucai,Ma Xiaoyue,Zhao Kaifeng,Zhang Shiyu,Bai Yapeng
Highly cross-linked polyurethanes based on Diels–Alder (DA) reaction have high hardness but poor toughness. A modified polyurethane with three-furyl diol (TF) was synthesized innovatively to improve its mechanical properties. Three-furyl diol (TF) and hydroxyl terminated polyurethane IDI-TF were synthesized first. Then the reaction of IDI-TF with xylene bismaleimide (BMI) generates cross-linked polyurethane ITB-PU (its soft segment content is 11.5%). Finally, the properties of the polyurethane ITB-PU were characterized by a series of methods. It can be observed that the DA reaction occurred at 50.33 °C, the r-DA reaction at 69.55 °C. When heated at 80 °C for 6 h, the self-healing efficiency of the ITB-PU was 43.91% known from the tensile test, and cracks on it virtually disappeared seen from polarizing microscope (POM). When heat was preserved for 12 h, the self-healing efficiency can reach 80.02%.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2018
·
IF 2.631
Ting Zheng,Jiaojiao Fang,Qinglong Xie,Zhenyu Wu,Meizhen Lu,Fan Xia,Dongshun Deng,Yong Nie,Jianbing Ji
Fatty acid 2-ethylhexyl esters are used for the eco-friendly production of biolubricant. There are several reports on their synthesis, but thermodynamics and transport data of these compounds are lacking. Herein, density and viscosity of palmitic acid 2-ethylhexyl ester, stearic acid 2-ethylhexyl ester and soya oil 2-ethylhexyl esters in the temperature range of T = (298.18–368.15) K at atmospheric pressure were measured and the vapor pressure in the temperature range of T = (476.95–500.85, 477.05–498.05, 477.75–500.05) K was determined. The obtained experimental data were correlated using temperature-dependence correlation equations, and the correlation coefficients of all the equations were over 0.999. In order to examine the reliability of the data, the GCVOL group method was used to evaluate densities for these fatty acid 2-ethylhexyl esters with the maximum relative deviation of −1.34%. The experimental viscosity data of synthesized 2-ethylhexyl esters were compared with those of lauric acid 2-ethylhexyl ester, palmitic acid n-octyl ester and oleic acid 2-ethylhexyl ester from previous studies. In addition, the molar enthalpy of vaporization at the mean temperature of the experimental range was calculated for the first time using the Clausius-Clapeyron equation.
研究领域:
物理化学
·
热力学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Yan-Peng Ni,Qi-Tian Li,Lin Chen,Wan-Shou Wu,Zi-Hao Qin,Yi Zhang,Li Chen,Xiu-Li Wang,Yu-Zhong Wang
Currently, it is still a huge challenge to prepare flame-retardant polymeric materials with excellent fire safety, high strength, good durability and processability. We here propose a H-bonding cross-linking strategy that can simultaneously endow polymers with excellent flame retardancy, non-dripping behavior and enhanced strength. In this work, a novel benzimidazole monomer, 2-(4-methoxycarbonyl-phenyl)-1H-benzimidazole-5-carboxylic acid methyl ester (PBM) has been designed as a H-bonding cross-linking monomer to prepare poly(ethylene terephthalate)-based copolyesters (PET- co -PBMs). Interestingly, along with the hydrogen bonding, the π-π stacking interactions from the benzimidazole groups also exist. Due to the formation of physical crosslinking network via hydrogen bonding and π-π stacking, the melt strength of copolyesters are greatly improved. Combining with char forming ability of benzimidazole, PET- co -PBMs display excellent fire safety. Moreover, PET- co -PBMs also exhibit higher glass transition temperature, higher mechanical strength and good processability. This work provides a promising strategy to design polymers with high strength, good processability, excellent flame retardance and anti-dripping performance.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
Polymers
·
2018
·Vol. 10
·期 4
·378
·
IF 2.935
Xiaomin Luo,Wenjie Hu,Min Cao,Huijun Ren,Jianyan Feng,Mengyuan Wei
A large amount of research has been devoted to developing novel superhydrophobic coatings. However, it is still a great challenge to pursuean environmentally friendly method that leads to superhydrophobic coatings. Herein, we demonstrate for the first time, an environmentally friendly method for the preparation of conductive superhydrophobic coatings with sandwich-like structures by using aminoethylaminopropyl polydimethylsiloxane modified waterborne polyurethane (SiWPU) andN-octadecylamine functionalized multi-wall carbon nanotubes. These environmentally friendly coatings with the sheet resistance of 1.1 ± 0.1 kΩ/sq exhibit a high apparent contact angle of 158.1° ± 2° and a low sliding angle below 1°. The influence of the surface texture before and after heat treatment on the wetting properties is discussed. In addition, the coatings can be electrically heated by 3~113 °C with a voltage of 12~72 V, and thus, can be used for deicing. Furthermore, the resulting coatings demonstrate good performance of wear resistance and ultraviolet resistance, which will have broad application potential in harsh environments.Keywords:environmentally friendly;conductivity;polyurethane
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
PubMed
高影响因子
E-POLYMERS
·
2021
·Vol. 21
·期 1
·336-345
·
IF 2.025
Wen-Bo Neng,Wen-Guang Xie,Bo Lu,Zhi-Chao Zhen,Jun-Long Zhao,Ge-Xia Wang,Jun-Hui Ji
A series of novel biodegradable copolyesters named poly(butylene 3-methyl adipate co -terephthalate) (PBA m T) were synthesized from the monomers of 3-methyl adipic acid (AA m ), 1,4-butanediol (BDO), and terephthalic acid (TPA) through a process of esterification and polycondensation. 1 H NMR analysis shows that they are random copolymers whose composition can be well controlled by the feed ratio of monomers. From the results of DSC and XRD, the introduction of methyl group successfully destroys the crystallizability of the PBA m chains, thus making it become a relative soft segment compared to PBA, while these random PBA m T copolymers constructed by soft segment PBA m and rigid segment PBT change from semi-crystalline polymers to nearly amorphous polymers as the feed ratio of A m increases. Especially, mechanical tests reveal that the copolymers show outstanding elasticity and rebound resilience with excellent strength. These thermoplastic copolyester elastomers with good performance by simply introduction of branched methyl group on polybutylene adipate terephthalate (PBAT) copolymer chains may well explore the potential application of biodegradable PBAT-based material.
Graphical abstract
Methyl branched PBA m T possesses excellent elasticity and shows certain degradation performance.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
APPLIED ENERGY
·
2017
·
IF 7.182
Yi-Tong Wang,Zhen Fang,Xing-Xia Yang
Biodiesel production was catalyzed by a novel magnetic carbonaceous acid (Zr-CMC-SO 3 H@3Fe-C 400 ) with both Brønsted and Lewis sites synthesized by a four-step method: (i) metal (Fe) ion chelation, (ii) calcination, (iii) metal (Zr) ion chelation and embedding, and (iv) sulfonation. It catalyzed the esterification of oleic acid with 97% biodiesel yield, transesterification of high acid value (AV) soybean oil with 95% biodiesel yield, and pretreatment of Jatropha oil with AV reduced from 17.2 to 0.7 mg KOH/g. Biodiesel yields (>90%) at 90 °C for 4 h reaction time were obtained for ten cycles by easy magnetic separation which showed potential practical applications in the field of green production. The synthesized catalyst was characterized with elemental analysis, XRD, ICP-OES, FT-IR, BET, VSM, SEM-EDX, HRTEM, TG-DSC and Boehm titration.
研究领域:
化学工程
·
可再生能源
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Haoyu Wang,Jinghui Wang,Mei Cui,Rongxin Su,Renliang Huang
The oil-absorbent sponge is effective in the prevention and cleanup of offshore oil spills. However, biofouling in marine environments will significantly reduce its oil absorption capacity. Herein, a novel type of antifouling and superhydrophobic polyurethane (PU) sponge was successfully prepared via grafting Econea (antifouling agent) to diisocyanate monomer and hydrophobic modification of PDMS (Polydimethylsiloxane) and SiO 2 . The prepared PDMS-SiO 2 @PU-Econea sponge shows not only super-hydrophobicity with a WCA of 154.5° but also excellent antifouling properties with more than 99% of inhibition to Escherichia coli after immersed in artificial seawater (salinity ≈35‰) for 50 days. It can absorb 133.9 times of trichloromethane than its own weight and still maintain 98.5% of absorption after 50 cycles. In addition, the PDMS-SiO 2 @PU-Econea sponge exhibits excellent continuous oil–water separation performance. The separation fluxes of n-hexane and dichloromethane are 151.0 and 136.3 L·h −1 ·g −1 , respectively, and the oil–water separation efficiency is up to 99.9%, it can absorb 50 times of crude oil than its own weight in 75 s. Therefore, the antifouling and superhydrophobic PDMS-SiO 2 @PU-Econea sponge is a promising and applicable oil absorbent sponge for long-term oil/water separation and cleanup of oil spills in marine environment.
研究领域:
材料科学
·
环境科学
·
海洋学
✓ 已验证
DOI
高影响因子
JOURNAL OF BIOMATERIALS APPLICATIONS
·
2024
·
IF 2.3
Fuhua Sun,Lishi Yang,Yi Zuo
To fabricate electroactive fibrous membranes and provide simulated bioelectric micro-environment for bone regeneration mimicking nature periosteum, a series of electroactive polyurethanes (PUAT) were synthesized using amino-capped aniline trimers (AT) and lysine derivatives as chain extenders. These PUAT were fabricated into fibrous membranes as guided bone tissue regeneration membranes (GBRMs) via electrospinning. The ultraviolet-visible (UV-vis) absorption spectroscopy and cyclic voltammetry (CV) of PUAT copolymers showed that the electroactive PUAT fibrous membranes had good electroactivity. Besides, the introduction of AT significantly improved the hydrophobicity and thermal stability of PUAT fibrous membranes and decreased the degradation rate of PUAT fibers in vitro. With the increasing content of AT incorporated into copolymers, the tensile strength and Young’s modulus of PUAT fibrous membranes increased from 4 MPa (PUAT0) to 15 MPa (PUAT10) and from 2.1 MPa (PUAT0) to 18 MPa (PUAT10), respectively. The cell morphology and proliferation of rat mesenchymal stem cells (rMSCs) on PUAT fibers indicated that the incorporation of AT enhanced the cell attachment and proliferation. Moreover, the expression levels of OCN, CD31, and VEGF secreted by rMSCs on PUAT fibers increased with the increasing content of AT. In conclusion, an electroactive polyurethane fibrous membrane mimicking natural periosteum was prepared via electrospinning and showed good potential application in guiding bone tissue regeneration.
研究领域:
生物材料学
·
组织工程
·
再生医学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）