JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 128
·期 6
·3925-3932
·
IF 1.289
Shenghua Lv,Haobo Ju,Chaochao Qiu,Yujuan Ma,Qingfang Zhou
Preparation and characterization of polycarboxylate superplasticizers of IPCs ( copolymer of itaconic acid and allyl polyoxyethylene ether) and MPCs (copolymer of maleic anhydride and allyl polyoxyethylene ether) are shown. The difference between IPCs and MPCs is that half of the carboxyl groups of IPCs indirectly connect to the main chains through methylene. The effects of the carboxyl group-main chain connection mode on the properties of IPCs and MPCs were investigated by assessing the paste fluidity and the pore diameters and compressive strength. The interaction between IPCs (MPCs) and cement were revealed by zeta-potential and the adsorption amount. The results indicated that the indirect connection mode favorably improved paste fluidity, decreased pore diameters, and increased the compressive strength compared with the direct connection mode. This is likely because that when carboxyl groups are connected to the main chains indirectly, more moving space allows easier adsorption on cement particles. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2016
·
IF 2.421
Fan-rong Kong,Li-sha Pan,Chen-man Wang,De-la Zhang,Nai Xu
Effects of polycarboxylate (PCE) superplasticizers with different densities of carboxylate groups, functional group contents, molecular weight, and side chain polymerization degrees on the hydration behavior of Portland cement were investigated in this study. The experiments were conducted by using semi-adiabatic calorimeters equipped with a temperature measurement system. The water cement ratio (W/C) was 0.4, and the PCE dosage used was 0.3%. Besides, the Total Organic Carbon (TOC) experiments were taken to further study the delaying mechanism of different PCE on cement hydration. The ability to delay hydration increased in PCEs with high densities of carboxylate groups, short side chains, and high molecular weight and the copolymerization of methyl acrylate (MA) monomers decreased the heat flow peak. Nevertheless, the main hydration temperature peak and the maximum elevated temperature decreased when the density of the carboxylate groups increased. Moreover, PCEs with only a moderate molecular weight had the lowest hydration degree. The main hydration peak decreased but appeared in advance when the amount of MA monomers copolymerized with PCEs was increased; the hydration degree also decreased. PCEs only polymerized by methyl allyl polyethenoxy ether (TPEG400) macromonomer had a hydration degree of 69.46%. Absorption amount results indicate that PCEs affect the hydration of cement paste by absorbing PCEs on the surface of cement particles or encapsulating some cement particles to restrain cement hydration. PCEs grafted with MA hydrolyzed to carboxylic and hydroxyl groups, which can both restrain the hydration of cement paste.
研究领域:
建筑材料学
·
化学工程
✓ 已验证
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2021
·
IF 2.545
Xingliang Li,Juncai Lu,Wanjun Mu,Baihua Chen,Daibing Luo,Bijun Liu,Yanqiu Yang,Hongyuan Wei,Shuming Peng
Nitrilotri–3–propanoic Acid (NTPA) and Tris(2–carboxyethyl) phosphine (TCEP) possess similar skeleton. This pair of isostructural ligands is a perfect set to assess the differences of uranyl (UO 2 2+ ) complexes with N–tricarboxylate versus P–tricarboxylate. The protonation reactions of NTPA and TCEP were investigated by potentiometry and calorimetry. Complexation of uranyl with the both ligands was studied by potentiometry and structural analysis. The results indicate that central trialkylamine in NTPA has a higher affinity for the proton than trialkylphosphine in TCEP. Crystal structures and NMR analyses indicate that central amine of NTPA and central phosphine of TCEP are not involved in the bonding. NTPA/UO 2 2+ complex is more stable than TCEP/UO 2 2+ complex. This difference cannot be explained by electronic effect of central N and P atoms because of nonbonding interactions. The higher stability of UO 2 2+ /NTPA versus UO 2 2+ /TCEP may be due to the fact that the central N atom of NTPA has a lower steric hindrance than the central P atom of TCEP. Another possible reason is that UO 2 2+ /TCEP complexes have different coordination modes from UO 2 2+ /NTPA complexes.
研究领域:
化学
·
配位化学
·
核化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2023
·
IF 3.8
Xiao-Lan Tong,Qiao-Lin Luo,Jian-Hua Xin,Shu-Juan Liu,Fen Liu,Jian-Hua Ding,Chen Xiong,Min Li,Jian-Qiang Luo,Jian-Bo Xiong
One novel uranyl carboxylate complex [(UO 2 ) ( L) ·2H 2 O] ( 1 ) (H 2 L =4-carboxymethoxy-benzoic acid) was synthesized under hydrothermal conditions by the reaction of UO 2 (NO 3 ) 2 ·6H 2 O and H 2 L in aqueous system. X-ray analysis of single crystal structure determined that complex 1 exhibits one-dimensional ribbon structure, in which, the UO 2 2+ ions are bridged by L 2− . The one-dimensional chains are further connected into 3D supramolecular network by O H…O hydrogen bond interactions between the coordinated water molecule and the coordinated carboxylic oxygen. The π…π interactions between adjacent benzene rings also contribute the structure formation. Complex 1 exhibits emblematic charge-transfer green emission of uranyl-bearing complexes. The UV–vis absorption spectra reveal distinct light absorption both on the ultraviolet and visible regions for 1 . Photocatalytic degradation of rhodamine B (RhB) in aqueous solutions using Complex 1 was studied, 78.3% of the RhB was degraded in only 80 min. Our obtained uranyl coordination polymer represents effective RhB photocatalytic degradation materials in aqueous solution. Infrared spectroscopy, TGA and PXRD were also discussed.
研究领域:
无机化学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
·
2024
·Vol. 36
·期 9
·04024251
·
IF 3.1
Cuizhen Zhang,Xinde Tang,Xiaodong Chen,Haichao Guo,Xuefan Li,Laixue Pang,Yong Yang,Fuying Dong
Polycarboxylate superplasticizers (PCEs) have been extensively used in the areas of construction and building; however, the application limitation of PCEs has emerged owing to their sensitivity to clay. In this work, three anticlay PCEs were synthesized by introducing acrylamide (AM), methacryloxyethyltrimethyl ammonium chloride (DMC), or 3-[2-(methacryloyloxy) ethyl] dimethylammonio-propane-1-sulfonate (DMAPS) into the polycarboxylate copolymer of ethylene glycol monovinyl polyethylene glycol ether (EPEG) and acrylic acid (AA), denoted as A-PCE, D-PCE, and S-PCE, respectively. The structures of these superplasticizers were characterized by gel permeation chromatography (GPC) and Fourier-transform infrared spectroscopy (FTIR). Compared with the common polycarboxylate superplasticizers (O-PCEs), the resultant anticlay PCEs showed better dispersion as far as the fluidity of cement paste and mortar were concerned. With the content of 0.5% per weight sodium bentonite in place of cement, these anticlay PCEs exhibited better clay resistance than O-PCE. In addition, the compressive strengths of mortar and concrete by the addition of A-PCE, D-PCE, or S-PCE were slightly higher than those of O-PCE. Total organic carbon (TOC) revealed that the sensitivity of A-PCE, D-PCE, and S-PCE to clay was lower than that of O-PCE. X-ray diffraction (XRD) proved that the layer spacing of clay increased after treatment with superplasticizer. In combination of adsorption determination with XRD analysis, a possible mechanism was proposed. Unlike the PEG side chains inserting into the clay layers for O-PCE, the cations in functional groups entered the clay layers through cation exchange for anticlay PCEs preferentially.
研究领域:
建筑材料
·
化学工程
·
土木工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COORDINATION CHEMISTRY
·
2021
·
IF 1.751
Le Guo,Yan-Peng Gao,Yan-Hua Lv,Li Wang,Yu Han,Fei Chang
We report the synthesis, crystal structures, and magnetic properties of a series of two-dimensional (2-D) and three-dimensional (3-D) coordination polymers (CPs). A solvothermal reaction of manganese metal salts with 4,4′-oxydibenzoic acid (H2oba), 4,4′-methylenebis(oxy) dibenzoic acid (H2mba), 4,4′-(propane-1,3-diylbis (oxy))dibenzoic acid (H2pba) or 1,4-bis (1H-imidazol-1-yl)-butane (bib) gives five new non-interpenetrating CPs, [Mn2(oba)2(CH3OH)(H2O)] (1), [Mn6(oba)6(bib)(DMF)2(H2O)4] · (DMF)2(CH3OH) (2), [Mn4(mba)4(bib)(CH3OH)] (3), [Mn7(pba)7 (bib)(H2O)4] · (H2O)3(DMA)(CH3OH)0.5 (4), and [Mn7(pba)7(H2O)6](DMA)3 (5). The X-ray crystal structural analyses revealed that 1, 4, and 5 are 2-D layers, whereas 2 and 3 are 3-D frameworks with 1-D Mn-carboxylate chains. In 1, 2, 4, and 5, the 1-D Mn-carboxylate chains are formed by flexible carboxylate ligands and Mn ions; these were then linked by organic ligands in different directions, leading to the formation of 2-D and 3-D frameworks. Furthermore, IR, PXRD, elemental analysis, TGA, and magnetic properties have been investigated.
研究领域:
无机化学
·
材料科学
·
固体化学
✓ 已验证
DOI
高影响因子
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
·
2018
·Vol. 32
·期 17
·1521-1528
·
IF 1.97
Sheng-Kang Wang,Xian-Yong Wei,Sheng Li,Fang-Jing Liu,Yu-Gao Wang,Zhan-Ku Li,Chong Shi,Zheng Yang,Zhi-Min Zong
Rationale Coal oxidation produces carboxylic acids (CAs), including aliphatic acids, benzoic acids, and benzenepolycarboxylic acids, which are important fine chemicals which could be used to understand the structural features of coals. However, detecting CAs usually presents great challenges due to extremely troublesome pretreatments. Therefore, it is essential to develop an analytical method for the rapid detection of CAs from coal oxidation. Methods A series of model compounds (MCs) of oxidation products and two practical samples were investigated by direct analysis in real time time-of-flight mass spectrometry (DART-TOFMS) under three different analytical conditions (ionizing gas temperature, organic solvent, and MC concentration). Results Ionizing methyl benzoate, dimethyl phthalate, and dimethyl adipate produces typical ions of methyl esters, including [M − OCH 3 ] + , [M + H] + , and [M + NH 4 ] + . In contrast, the characteristic ions generated from CAs are polymer ions, such as [2 M + NH 4 ] + , [3 M + NH 4 ] + , [4 M + NH 4 ] + , and [5 M + NH 4 ] + , indicating the strong intermolecular hydrogen-bond interaction among CAs. Conclusions Results suggest that DART-TOFMS could rapidly analyze CAs or esters in coal oxidation products according to their typical ions to further gain deep insights into the coal structure.
研究领域:
分析化学
·
能源化学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2021
·
IF 4.311
Zifei Yan,Zeyu Ma,Jian Deng,Guangsheng Luo
The ring-opening reactions of epoxides with carboxylic acids have great applications in the coating and polymer industry. However, the systematical study on the structure-activity relation of catalysts is still scarce. In this work, the carboxylate catalysts were directly prepared rather than using the traditional catalysts like amines or quaternary ammonium salts, thus removing the induction period and making the kinetic results more accurate and rigorous. The reaction orders of reactants and catalyst were obtained by kinetic experiments, and based on that, the kinetic equation and mechanism were put forward. The influences of solvent environment, as well as the structure and properties of catalysts on their activity were further studied. It was found that the alkalinity of the carboxylate ions and the electrostatic interaction are the key factors to affect the nucleophilicity of catalysts. Generally, the nucleophilicity is enhanced with the increase of cation radius and anion branches.
研究领域:
有机化学
·
催化
·
高分子科学
·
材料科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 50
·期 3
·1060-1068
·
IF 4.174
Run-Ze Yuan,Peng-Fei Cui,Shu-Ting Guo,Guo-Xin Jin
Herein, we describe the synthesis of tetraphenylphosphonium o-carboranyl dithiocarboxylate (Ligand 1) and methyldithiocarboxyl-o-carborane (Ligand 2). The complexes [Cp*M(o-C2B10H11CS2)Cl] (M = Ir (3); Rh (4)) and [Cp*M(o-C2B10H11CS2)2] (M = Ir (5); Rh (6)) have been synthesized based on Ligand 1. The selective B–H bond activation of Ligand 2 has also been explored, leading to the synthesis of the B–H activated complex [Cp*Ir(o-C2B10H10CS2CH3)Cl] (7) and four of its substituted derivatives (8, 9, 10 and 11). All of these compounds have been characterised through single-crystal X-ray diffraction, NMR, IR spectroscopy and elemental analysis.
研究领域:
无机化学
·
配位化学
✓ 已验证
DOI
高影响因子
World Journal of Engineering
·
2014
·Vol. 11
·期 3
·271-278
·
IF 0
Leqin He,Jiquan Zhao,Shenjun Qin,Tao Chang,Yuecheng Zhang,Guangqing Zhang,Xiaorui Gao
Five halogen-free amphiphilic Brønsted acidic ionic liquids (ILs) based on 3-(N,N-dimethylalkylammonium)-propanesulphonate quaternary ammonium zwitterions andp-toluene sulphonic acid monohydrate were synthesized. The IL structures were characterized using1H NMR,13C NMR and (ESI)-MS. The IL thermal instability was characterized using TG-DSC. The ILs were used as dual-solvent catalysts for esterification of several carboxylic acids, with different alcohols under mild conditions to study relevant structure-activity relationships. Results showed that the miscibility of the acidic IL, which is affected by the length of the carbon chain in the cation, is an important factor influencing the activity of the catalyst for the esterification reaction. Post-processing steps were simple, and the catalyst could be reused easily.
研究领域:
化学
·
催化科学
✓ 已验证
DOI
PROGRESS IN ORGANIC COATINGS
·
2017
·
IF 2.858
Xian-Wei Cheng,Jin-Ping Guan,Xu-Hong Yang,Ren-Cheng Tang
This research work reported a novel approach to develop flame retardant silk fabric using naturally occurring phytic acid (PA) rich in phosphorus and TiO 2 nanoparticles through a pad-dry-cure technique. A polycarboxylic acid [1,2,3,4–butanetetracarboxylic acid (BTCA)] was employed to stabilize and improve the adhesion of TiO 2 on silk surface. The flame retardancy of the treated silk fabric was determined in terms of limiting oxygen index, vertical burning, and pyrolysis combustion flow calorimetry, and the durability of flame retardancy to washing was discussed. PA and TiO 2 were found to have a joint flame retardant effect. The combination of PA, TiO 2 and BTCA was able to endow silk fabric with excellent flame retardancy, and the good flame retardant ability was kept even after 25 times of washing. The reasons for the good washing durability of the treated silk fabric were discussed. Finally, a significant condensed-phase flame retardant mechanism of the silk fabric treated with the PA/TiO 2 /BTCA system was revealed by the analyses of thermogravimetry and pyrolysis combustion flow calorimetry.
研究领域:
纺织科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2022
·
IF 4.198
Tianhao Xu,Xingyu Zhou,Xiong Xiao,Yan Yuan,Long Liu,Tianzeng Huang,Chunya Li,Zhi Tang,Tieqiao Chen
A nickel-catalyzed decarbonylative thioetherification of carboxylic acids with thiols was developed. Under the reaction conditions, benzoic acids, cinnamic acids, and benzyl carboxylic acids coupled with various thiols including both aromatic and aliphatic ones produce the corresponding thioethers in up to 99% yields. Moreover, this reaction was applicable to the modification of bioactive molecules such as 3-methylflavone-8-carboxylic acid, probenecid, and flufenamic acid, and the synthesis of acaricide chlorbenside. These results well demonstrated the potential synthetic value of this new reaction in organic synthesis.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）