JOURNAL OF ORGANIC CHEMISTRY
·
2023
·
IF 3.6
Fenfen Xie,Fen Han,Yunying Yan,Haiqiong Li,Jianjun Hao,Linhai Jing,Pan Han
It is significant to develop novel difluoromethylation methods because of the important roles of difluoromethyl groups in the medicinal chemistry and material industries. Here, we developed a novel difluoromethylation–carboxylation and difluoromethylation–deuteration method triggered by a difluoromethyl radical generated by electroreduction of stable and easily available difluoromethyltriphenylphosphonium bromide. Various molecules containing difluoromethyl and carboxyl or deuterium groups can be synthesized through this method. The establishment of this method will provide an alternative to radical difluoromethylation reactions.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Yangqin Liu,Lei Chen,Lin Liu,Pengfei Shi,Junhui Sun,Yang Wang,Linmao Qian
Reducing wear and even achieving superlubrication in industrial applications using simple yet effective methodologies has been a longstanding research objective. In this study, we propose a convenient approach by employing a combination of carboxylated graphene (Gr-COOH) coating with glycerol as lubricants. Compared to the non-lubricated state, this strategy enabled the achievement of superlubrication with an exceptionally low friction coefficient of 0.002, while simultaneously reducing wear volume of substrate by 4 orders of magnitude, and the wear of the counterpart balls are nearly zero. The transfer of Gr-COOH to the ball surface led to the formation of a low shear resistance interface with the Gr-COOH present on the substrate. Nanoscopic experiments with atomic force microscopy revealed that the substrate surface lubricated by this method exhibited more hydrophilic properties. The formation of a featured hydrophilic interface enables the persistence of glycerol molecules in the contact region for an extended duration, thereby facilitating continuous elastohydrodynamic lubrication. This proposed lubrication methodology holds broad utilization potential as a wear-reduction strategy across various industrial fields.
研究领域:
材料科学
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Zhenchao Gu,Yu Sun,Li Zhang,Mengyang Lv,Lirong Chen
Carboxylated dyes are regarded as the most effective sensitizers for TiO 2 owing to their propensity to establish more stable ester bonds with the TiO 2 surface. Despite this advantage, the prevailing sensitization protocols lack well-defined guidelines, leading to suboptimal photocatalytic performance. As typical carboxylated dyes, tetracarboxyphenyl porphyrin and tetracarboxyzinc phthalocyanine were synthesized and anchored on TiO 2 under different conditions to investigate the regularities in the sensitization conditions of carboxylated dye-sensitized TiO 2 . Significant differences in the morphology of these catalysts can be observed under different sensitization conditions. Solvents with high dye solubility, low viscosity, and high polarity are deemed more suitable for the dye-sensitized systems. The dye ratio and the duration dictate the amount of anchored dye. Agglomeration of dyes caused by high temperatures or excess dye may seriously damage the performance of the photocatalysts. In summary, among commonly used solvents such as dichloromethane, methanol, ethanol, and DMF, DMF was identified as the optimal solvent for sensitizing TiO 2 with carboxylated dyes. A dye dosage of 1 × 10 -5 mol per gram of TiO 2 was found to be sufficient to achieve uniform surface coverage without causing multilayer adsorption or aggregation. Finally, this study investigated the mechanism of how dye sensitization conditions influence the process, and the principles for selecting sensitization conditions in the future were summarized.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Tian Huang,Yue Ma,Huangjingyi Chen,Meijuan Chen,Ruoxian Jia,Lin Lin,Yimin Fan
In this study, a maleic acid (MA) hydrolysis one-pot method is proposed to prepare carboxylated silk nanofibers (MA-SNFs). The MA concentration, hydrolysis temperature, and processing time were optimized. Combined with high-pressure homogenization, MA-SNFs with a carboxyl content of 0.617±0.019 mmol/g and length of 333±116 nm were obtained with a yield of 54.90±1.98 % at the optimal conditions: 50 wt% of MA concentration, 110 °C of hydrolysis temperature and 120 min of processing time. The morphology, chemical structure, and crystal structure of raw silk fibroin (SF), acid-hydrolyzed silk fibroin and nanofibers were studied. Furthermore, MA was reused several times with a recovery rate of >94 % and maintained almost the same treatment effect. Finally, due to the presence of carboxyl groups, MA-SNF hydrogels were successfully prepared by an acetic coagulation vapor bath which exhibited excellent self-supporting ability and mechanical properties as well as a more sensitive pH response compared with regenerated silk fibroin solution and other non-carboxylated silk nanofibers. The MA-SNF aerogels had the characteristics of light weight, high strength and porous with cross-linked nanostructures.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 137
·期 3
·48301
·
IF 2.188
Xin Li,Zhuang Liu,LunYu Zhu,ShanShan Miao,Zheng Fang,LiHuan Zhao,Kai Guo
Welan gum has disadvantages such as poor solubility, low viscosity, and poor crosslinking property, when it is applied in petroleum industry, comparing to guar gum. Two methods for the carboxylic modification of welan gum were developed, carboxyethyl modification and citric acid modification, to improve the solubility in water, viscosity, and crosslinking ability of welan gum in the borax crosslinking system. The solubility time of carboxyethyl modified and citric acid modified welan gum were shortened to 30 and 90 min, respectively. The highest viscosity of citric acid modified product was 49.4 mPa s, the viscosity after crosslinking was raised at least 1.2 times to the highest four times than that before crosslinking. The results indicated three factors affecting the properties of modified products: (1) how many function groups in the modifying agent; (2) the way to connect the function group; and (3) the whole structure of the modifying agent. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48301.
研究领域:
材料科学
·
石油工程
·
应用化学
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2012
·
IF 3.628
Su Yixue,Chu Bin,Gao Yuan,Wu Chaoxi,Zhang Lingmin,Chen Peng,Wang Xiaoying,Tang Shunqing
In order to improve bioactivity of agarose, we modified agarose by carboxylation and grafting dopamine. Under alkaline condition, carboxylated agarose was prepared using 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation system by oxidizing C 6 hydroxyl on d -galactose ring into carboxyl group, and the maximum value of the degree of carboxylation reached 30%. With the increase of the amount of oxidant, the molecular weight of the carboxylated agarose decreased to 4 kDa by gel permeation chromatography (GPC) measure. Carboxylated agarose reacted with dopamine through EDC condensation reaction to obtain agarose grafting dopamine (Ag-g-DA), and the grafting rate of dopamine was determined to be 9.3% by UV spectroscopy at 280 nm. The structures of these modified agaroses were determined by FT-IR and 13 C NMR. Both carboxylated agarose and Ag-g-DA showed no cytotoxicity and promoted cell-adhesiveness.
研究领域:
生物材料学
·
细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Omega
·
2024
·
IF 3.7
Jin Long Zhang,Xiao Wei Zhang,Bing Yuan,Heng Zhang,Xing Zhi Wang,Hao Wang,Hong Wei Zhao
Advances in chemotherapeutic strategies are urgently required to improve antitumor efficiency. Herein, a carboxylated pillar[6]arene (CP6A) was employed to load chemotherapy medication, nitrogen mustard (NM), via forming a direct host–guest complex, as this helps to decrease the cytotoxicity of NM on normal mammary epithelial cells. Attributed to the stronger complexation ability of CP6A for endogenous spermine (SPM) than for NM, the complexed NM could be competitively released from the CP6A cavity via replacement with SPM. This chemotherapy strategy performed well in vitro and in vivo for SPM-overexpressed cancers. In comparison with free NM, antitumor efficiency of NM/CP6A was significantly enhanced, which originated from the synergistic effect of competitive release of NM and simultaneous trapping of SPM. This strategy might guide expansion to other first-line antitumor agents to improve therapeutic efficacy and decrease side effects, thereby replenishing the possibilities of supramolecular chemotherapy.
研究领域:
药学
·
肿瘤学
·
超分子化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Zuoyu Jia,Fengkai Liang,Xinze Xu,Haifeng Zhou,Yaqing Zhang,Peng Liang
The removal of multiple heavy metal pollutants remains a challenge. Amination and carboxylation modified lignins (NCLs) prepared by one-pot hydrothermal method were used as adsorbents for Cr(VI) and Cd(II) removal. The oxygenous groups content in adsorbents was quantitatively analyzed by Boehm titration in which NCL10 (the mass ratio of citric acid: triethylene diamine = 10) possessed a maximum carboxyl group content of 1.22 mmol/g. The Langmuir adsorption isotherm model was the most suitable, with the highest theoretical adsorption capacity of Cr(VI) and Cd(II) of 1298.6 and 103.1 mg/g, respectively. Meanwhile, FT-IR and XPS exhibited that NCL5 surface contained many functional groups beneficial to the removal of Cr(VI) and Cd(II). The contribution of carboxyl and hydroxyl groups to the removal of Cr(VI) and Cd(II) was quantitatively analyzed. After the blocking of carboxyl and hydroxyl groups, the adsorption rate of Cr(VI) and Cd(II) decreased by 26.4 %, 67.7 % and 7.2 %, 43.3 %, respectively. This study provides effective strategies to overcome the limitations of lignin adsorbents for wastewaters containing a wide range of heavy metal pollutants.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Xiao-lei Wang,Wei Qin,Li-xin Wang,Kong-yin Zhao,Hui-cai Wang,Hong-yu Liu,Jun-fu Wei
In order to recover dyes from textile wastewater, a self-supported carboxylated titanium dioxide/calcium alginate (TiO 2 -COOH/CaAlg) hydrogel nanofiltration membrane was prepared using TiO 2 -COOH as the reinforcing agent. The Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) mapping scanning spectra were employed to characterize the distribution of TiO 2 -COOH nanoparticles on the membrane surface. The pore size distribution, zeta potential and mechanical performance of the membrane were evaluated. The rejections for single dye solutions, salt solutions and dye/salt mixture solutions were also examined. The results indicate that the TiO 2 -COOH nanoparticles are dispersed uniformly on the membrane surface. Compared to CaAlg membrane, the tensile strength of 20 wt% TiO 2 -COOH/CaAlg membrane is enhanced by 328%. At the operating pressure of 0.1 MPa, the rejection ratios of 20 wt% TiO 2 -COOH/CaAlg membrane for 100 mg/L Brilliant blue G250, Direct black 38 and Congo red are 98.4%, 96.8% and 95.9% respectively, and the permeate flux is about 14.1 L·m −2 ·h −1 . Meanwhile, this membrane possesses the low rejection ratios for inorganic salts (16.1%, 15.6%, 12.3% and 9.0% for MgSO 4 , Na 2 SO 4 , MgCl 2 and NaCl, respectively), excellent dye anti-fouling property and good stability in the long-term filtration for dye/salt mixture solution.
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2019
·
IF 0
Arun Saini,Chandravati Yadav,Bai-Liang Xue,Nan Wang,Lei Dai,Xinping Li
In this study, a mixed-acid-assisted system utilizing a combination of a weak acid (citric acid, CA) and strong acid (H2SO4, SA) under hydrothermal reaction conditions was proposed for simultaneous preparation and modification (carboxylation) of cellulose nanocrystals (CNCs). Bleached bamboo pulp was used as the cellulose source, and the optimized reaction conditions were further used to produce carboxylated CNCs (cCNCs) from microcrystalline cellulose and Whatman 1 filter paper. Different concentrations of CA and SA (namely, 40 wt % CA (optimized concentration) and 5, 10, 20, and 30 wt % SA) were used for the hydrolytic processing of raw cellulosic material under hydrothermal conditions. The effect of various concentrations of CA and SA on the yield, carboxylate content, microstructure, crystallinity, thermal, and rheological characteristics of cCNCs were methodically investigated and contrasted. The optimized hydrothermal reaction conditions performed for 4 h at 100 °C using a mixture of 40 wt % CA and only 20 wt % SA yielded needle-shaped cCNCs with a yield higher than 70%. The carboxyl functionalization of CNCs was affirmed through Fourier transform infrared spectroscopy and conductometric titrimetric method. The results revealed the carboxylate content of 1.18 mmol/g corresponding to an average degree of oxidation of ∼0.20. The length of nanocrystals lies in the range of 280–420 nm with diameter ranging from 10 to 20 nm, as was perceived through microstructural analytical tools like field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Dynamic light scattering analysis gives an average size of ∼200 nm. The visual inspection revealed high colloidal stability of cCNCs dispersions, which was further supported through its appreciable Zeta potential value of ca. −49.5 mV. Further, the rheological characterizations revealed typical features reminiscent of critical gels showing elastic behavior of cCNCs. Nanocomposite films of hydroxypropyl methylcellulose (HPMC) with different loadings of cCNCs were fabricated using a simple solvent casting method. The incorporation of very small amounts of cCNCs (0.1 wt %) in HPMC resulted in ∼58% increment in tensile strength, ∼10% increment in modulus, and ∼82% increment in elongation. Moreover, the composite films exhibited high transparency and appreciable water barrier properties that allow their potential application as barrier and transparent films for various applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
CARBOHYDRATE POLYMERS
·
2025
·
IF 12.5
Junbo Chen,Yuanpeng Xie,Maosong Tian,Jingfu Tian,Zhihao Liang,Haibo Xie,Menglan Lv
Cellulose has drawn much attention in the field of interfacial solar steam generation (ISSG) due to its advantages of renewability, abundant availability, and hydrophilicity. However, the hydroxyl groups of cellulose form weak hydrogen bond interaction with water, resulting in high evaporation enthalpy and thereby low evaporation rate. Herein, carboxylic acid groups possess of strong interaction with water were introduced into cellulose hydrogel to fabricate efficient ISSG. The carboxylated cellulose hydrogels feature excellent hydrophilicity and water supply capacity because of its rich hydroxyl groups, carboxyl groups, and pore structure. More importantly, the carboxyl groups can effectively weaken the hydrogen bond interactions between water molecules, resulting in larger intermediate water contents that reduced water vaporization enthalpy as small as 1198 J g −1 . Consequently, the evaporator shows a remarkable evaporation rate of 3.68 kg m −2 h −1 under one sun irradiation when using bamboo carbon black as the photothermal material. Moreover, the evaporator exhibits superior seawater and sewage purification capabilities, along with outstanding salt resistance. This work presents an advisable strategy of cellulose structure design for interfacial solar evaporation.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Huaichang Wang,Xiaobo Wang,Mengran Yu,Jianing Li,Juming Liu
As a classical photocatalyst, nano-TiO2 has been widely investigated globally. However, achieving its photocatalytic activity within the spectral range of 400 to 740 nm through a facile approach remains a challenge. Herein, carboxylated carbon species sensitized nano-TiO2 was successfully synthesized by a low-temperature (300 °C) carbonization method using ethanol as carbon source and modifier and commercially available nano-TiO2 as titanium source. The obtained sensitized TiO2 nanoparticles exhibited excellent full visible-light-driven photocatalytic degradation performance. The synthesized TiO2 samples were comprehensively analyzed using a range of characterization techniques. The results indicate that the sensitization of carboxylated carbon species endows the nano-TiO2 with full-visible light spectral response properties and facilitates the separation of photogenerated electron–hole pairs, which leads to excellent full visible-light-driven photocatalytic degradation performance. This study presents a novel strategy for broadening the spectral response and facilitating the industrial scale-up of commercially available nano-TiO2.
研究领域:
材料科学
·
环境科学
✓ 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）