DALTON TRANSACTIONS
·
2024
·
IF 3.5
Peiyao Liu,Zhengzeng Yang,Mengyuan Zhang,Yufeng Liu,Dandan Han,Dan Wu,Charles Chunbao Xu,Jianshe Wang
C-H carboxylation of furoic acid (FA) with CO2 is an atom-efficient strategy to produce 2,5-furandicarboxylic acid (2,5-FDCA) from lignocellulose. The existing carbonate-promoted CO2 carboxylation processes rely on the use of large amounts of expensive Cs2CO3 as deprotonating reagent and molten salt. Substitution of Cs with other cheap and abundant alkali ions (such as K and Na) can reduce the use of Cs, but faces the problem of low yield of 2,5-FDCA. This study found that the addition of catalytic amounts of ZnCl2 as a Lewis acid can increase the yield of 2,5-FDCA in the CO2 carboxylation reaction of Na/K-FA in a molten salt reaction system. 1H NMR analysis and DFT calculations confirmed that ZnCl2 coordinates with the furan ring through electron transfer from the conjugated furan ring to Zn2+, thereby activating the H at the C5 position of Na/K-FA. This coordination lengthened the C5-H bond and lowered its heterolytic dissociation energy, making it more susceptible to being deprotonated by CO32- and subsequently carboxylated by CO2. The developed Lewis acid coordination strategy provides a new idea for the efficient construction of C-C bonds between CO2 and aromatics through carbonate-promoted C-H carboxylation.
研究领域:
化学工程
·
可再生资源转化
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
mBio
·
2024
·
IF 5.1
Jiejie Shen,Wenping Wu,Kangle Wang,Jingyi Wu,Bing Liu,Chunyang Li,Zijun Gong,Xin Hong,Han Fang,Xingwei Zhang,Xiaoling Xu
Acetyl-CoA carboxylases (ACCs) convert acetyl-CoA to malonyl-CoA, a key step in fatty acid biosynthesis and autotrophic carbon fixation pathways. Three functionally distinct components, biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and carboxyltransferase (CT), are either separated or partially fused in different combinations, forming heteromeric ACCs. However, an ACC with fused BC-BCCP and separate CT has not been identified, leaving its catalytic mechanism unclear. Here, we identify two BC isoforms (BC1 and BC2) from Chloroflexus aurantiacus, a filamentous anoxygenic phototroph that employs 3-hydroxypropionate (3-HP) bi-cycle rather than Calvin cycle for autotrophic carbon fixation. We reveal that BC1 possesses fused BC and BCCP domains, where BCCP could be biotinylated by E. coli or C. aurantiacus BirA on Lys553 residue. Crystal structures of BC1 and BC2 at 3.2 Å and 3.0 Å resolutions, respectively, further reveal a tetramer of two BC1-BC homodimers, and a BC2 homodimer, all exhibiting similar BC architectures. The two BC1-BC homodimers are connected by an eight-stranded β-barrel of the partially resolved BCCP domain. Disruption of β-barrel results in dissociation of the tetramer into dimers in solution and decreased biotin carboxylase activity. Biotinylation of the BCCP domain further promotes BC1 and CTβ-CTα interactions to form an enzymatically active ACC, which converts acetyl-CoA to malonyl-CoA in vitro and produces 3-HP via co-expression with a recombinant malonyl-CoA reductase in E. coli cells. This study revealed a heteromeric ACC that evolves fused BC-BCCP but separate CTα and CTβ to complete ACC activity.
研究领域:
生物化学
·
分子生物学
·
结构生物学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 15
·50190
·
IF 2.52
Haonan Cheng,Yunjie Yin,Bo Wang,Junrong Zhu,Chaoxia Wang
Fabrication of highly conductive poly(styrene)/poly(aniline) (PS/PANI) microspheres has been considerably explored. Improving the adsorption efficiency of aniline on the PS microspheres is still a challenge by facile methods. To overcome this problem, poly(styrene-co-methacylic acid) (poly(St-co-MAA)) is firstly synthesized for capturing anilinium ions, and then the in-situ polymerization of aniline is implemented to obtain highly conductive poly(St-co-MAA)/PANI microspheres. The prepared poly(St-co-MAA) microspheres bearing an average particle size of 238 nm possess a low polymer dispersity index (PDI, 0.082) and high zeta-potential, which guarantee no agglomeration and deposition of microspheres latex after 30 days at room temperature. After the in-situ polymerization of aniline, the conductive disc based on poly(St-co-MAA)/PANI microspheres presents a superior electrical conductivity of 14.6 S m −1 at an inferior PANI loading of 5.74 vol% and a relatively low electrical percolation threshold (EPT < 0.16 vol%). The results indicate that the carboxylic microspheres for preparing high polymer/PANI microspheres is effective. Meanwhile, poly(St-co-MAA)/PANI microspheres show a great potential in manufacture of conductive composites due to their excellent electrical conductivity.
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
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
·
2014
·
IF 3.679
Tie Jun Lin,Xuan Meng,Li Shi
A non-petroleum route to produce acrylic acid was investigated through hydrocarboxylation of acetylene with CO and water in the presence of Ni 2 O 3 and cupric bromide as combined catalysts. The activity of Ni 2 O 3 was compared with various homogeneous catalysts; the effect of initial total pressure, reaction temperature, molar ratio of CO/C 2 H 2 , the volume ratio of solvent/water, the catalyst amount and the role of promoters have been studied in detail. It was found that the acrylic acid space-time-yield as high as 764.6 mol AA/(mol Ni h) was obtained under the optimal experimental conditions. The Ni 2 O 3 catalyst could be reused at least five times without obvious loss of activity. The characterization of recovered catalysts by XRD, XPS, SEM and TG–DTG revealed that the state of nickel remains unchanged during the reaction, and there are three types of soft coke deposited on the surface of the catalyst. The catalysts can be regenerated through calcination within 400 °C according to TG curve.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2025
·
IF 7.9
Huiying Cheng,Jingchang Sun,Siwen Liu,Furong Cao,Liuting Shan,Zijiang Yang,Xiaofan Cui,Jiaxu Zhao,Zhen Qiao,Qiuju Feng
Low-grade heat (<100 °C) is abundant and ubiquitous in the environment, and the recovery of low-grade heat energy will be of great significance for the energy supply and the improvement of the environment. Low-cost and effective technologies for transforming low-grade heat into electricity are urgently needed. Thermocell (TEC) based on REDOX couples has become a promising technology for low-grade heat harvesting due to its advantages of low cost, scalability, and intrinsic high thermopower. To enhance its performance, different types of TECs need to incorporate various additives into the REDOX couples. However, there is currently no identical additive that effectively enhances the performance of both P-type and N-type TECs. In this paper, carboxylated chitosan is used as an identical additive, resulting in an increase in the Seebeck coefficient of P-type and N-type TECs by 115.33 % and 53.25 %, respectively. Furthermore, we introduce a novel sandwich-structured packing technique featuring a configuration of Metal/PET film/Carbon felt (MPC) for TEC. This approach effectively reduces both the cost and weight of the TEC, while the MPC structure further enhances their performance. The TEC can be scaled up to power electrical devices. Our achievement provides an effective strategy for harvesting low-grade heat energy.
研究领域:
能源材料
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
PLANT PHYSIOLOGY AND BIOCHEMISTRY
·
2025
·
IF 5.7
Minghao Jiang,Xin Chen,Tianqiao He,Wei Hu,Ning Zhao,Min Liao,Haiqun Cao
Chinese sprangletop ( Leptochloa chinensis (L.) Nees) is among the most economically damaging and disruptive weeds found in rice fields across China, and it exhibits a high degree of cyhalofop-butyl resistance for the past few years. Here, a suspected cyhalofop-butyl-resistant population HFCH5 (R) was collected from a rice field and analyzed to explore the mechanistic basis for its resistance activity. Compared with the susceptible HFLY1 (S) population, this R population exhibited differing levels of resistance to four ACCase-inhibiting herbicides (cyhalofop-butyl (RI = 11.52), fenoxaprop- P -ethyl (RI = 11.05), metamifop (RI = 6.61), and clethodim (RI = 4.06)), although it did exhibit susceptibility to florpyrauxifen-benzyl, tripyrasulfone, pyraclonil, and anilofos. This cyhalofop-butyl resistance in R plants was not effectively mitigated by pre-treatment with the cytochrome P450 inhibitor piperonyl butoxide or the glutathione S-transferase inhibitor 4-chloro-7-nitrobenzoxadiazole. Further analyses of these R plants revealed the substitution of Trp-1999 (TGG) for a Gly residue (GGG) within the ACCase carboxyltransferase domain. When the wild-type and mutated forms of this ACCase protein were subjected to structural modeling while complexed with a range of herbicides with ACCase-inhibiting activity, this Trp-1999-Gly substitution was found to be associated with a slight decrease in the affinity of this protein for a series of ACCase-inhibiting herbicides. A dCAPS marker was developed to aid in the rapid detection of this Trp (TGG)-1999-Gly (GGG) mutation within L. chinensis . Notably, before or after four ACCase-inhibiting herbicides (cyhalofop-butyl, fenoxaprop- P -ethyl, metamifop and clethodim) treatment, ACCase gene expression level of the R plants was not significantly higher (fold change <2, P > 0.05) than that of the S plants. This study is the first report that in grass species, the newly identified ACCase Trp-1999-Gly mutation is associated with ACCase-inhibiting herbicide resistance.
研究领域:
植物学
·
遗传学
·
农业科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of the American Chemical Society
·
2024
·
IF 14.4
Fei Fang,Xiao Sun,Yuanxu Liu,Weixin Huang
Methane (CH4) carboxylation with carbon dioxide (CO2) into acetic acid (CH3COOH) is an ideal chemical reaction to utilize both greenhouse gases with 100% atom efficiency but remains a great challenge under mild conditions. Herein, we introduce a concept of water (H2O) radiocatalysis for efficient and selective aqueous-phase CH4 carboxylation with CO2 into CH3COOH at room temperature. H2O radiolysis occurs under γ-ray radiation to produce ·OH radicals and hydrated electrons that efficiently react with CH4 and CO2, respectively, to produce ·CH3 radicals and ·CO2– species facilely coupling to produce CH3COOH. CH3COOH selectivity as high as 96.9 and 96.6% calculated respectively from CH4 and CO2 and a CH3COOH production rate of as high as 121.9 μmol·h–1 are acquired. The water radiocatalysis driven by γ-rays is also applicable to selectively produce organic acids from other hydrocarbons and CO2.
研究领域:
化学
·
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Yongjun Sun,Wenquan Sun,Kinjal J. Shah,Pen-Chi Chiang,Huaili Zheng
In this work, carboxylated chitosan modified flocculant (CC-g-PCD) was prepared by graft copolymerization technique to enhance the charge-attracting and adhesion of bridges and net-sweeping capacity of flocculants. The dimethyldiallylammonium chloride (DMDAAC), carboxylated chitosan (CMCS), and 3-chloro-2-chloropropyltrimethylammonium chloride (CTA) were utilized for synthesis of CC-g-PCD via photopolymerization techniques. The synthesized CC-g-PCD was characterized by 1 H NMR, SEM, XRD, and FTIR, and the characteristic groups on the main chain and surface morphological structure of CC-g-PCD were investigated. The obtained results indicated that CTA and DMDAAC were successfully grafted into the CPCTS. In ordered to evaluate the flocculation performance of CC-g-PCD at various dosages, stirring intensity (G value), and pH value by detecting Chl a, COD, and turbidity, the actual lake water that contains algae was used for flocculation assessment tests. The experimental results of the water sample with flocculation showed that the maximum flocculation efficiency of turbidity (91.1%), Chl a (97.2%), and COD (97.0%) can be achieved by CC-g-PCD at pH 7, G value 200 s −1 , and 4.0 mg/L. The comparison results demonstrated that CC-g-PCD had better flocculation efficiency than commercial flocculants. Finally, based on the analysis of algae removal in combination with Zeta potential measurements, the flocculation mechanisms in actual lake water at various dosages and pH values were adsorption bridging and electrical neutralization.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Fanqin Ji,Lina You,Lei Wang,Zhikai Liu,Yajun Zhang,Shanshan Lv
A “post-infiltration and subsequent photo-cross-linking layer-by-layer assembly” strategy was, for the first time, introduced to fabricate carboxylated chitosan (CCS) based antibacterial multilayer films with improved stability under alkaline conditions. Precursory polyelectrolyte multilayers were assembled from CCS and poly(allylamine hydrochloride) (PAH). 4,4′-Diazostilbene-2,2′-disulfonic acid disodium salt was then infiltrated to cross-link the multilayers under UV irradiation. Analysis by UV–vis spectra showed that absorbance at characteristic wavelengths of the multilayers increased almost linearly with number of CCS/PAH bilayers. AFM images indicated that surfaces of the cross-linked multilayers were rather uniform and stable against basic treatments. Surface wettability of the multilayers was determined by water contact angle measurements. The multilayers exhibited reasonable antibacterial properties against Gram-negative E. coli, demonstrating that the multilayers were active in preventing bacterial growth and represented a novel type of antibacterial films with improved stability under alkaline conditions. These results open new possibilities for building functionalized architectures onto polyelectrolyte multilayer films.
研究领域:
生物材料学
·
表面科学
·
微生物学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 10
·1550
·
IF 3.164
Zhen Li,Shunqi Mei,Yajie Dong,Fenghua She,Lingxue Kong
While electrospinning has been widely employed to spin nanofibers, its low production rate has limited its potential for industrial applications. Comparing with electrospinning, centrifugal spinning technology is a prospective method to fabricate nanofibers with high productivity. In the current study, key parameters of the centrifugal spinning system, including concentration, rotational speed, nozzle diameter and nozzle length, were studied to control fiber diameter. An empirical model was established to determine the final diameters of nanofibers via controlling various parameters of the centrifugal spinning process. The empirical model was validated via fabrication of carboxylated chitosan (CCS) and polyethylene oxide (PEO) composite nanofibers. DSC and TGA illustrated that the thermal properties of CCS/PEO nanofibers were stable, while FTIR-ATR indicated that the chemical structures of CCS and PEO were unchanged during composite fabrication. The empirical model could provide an insight into the fabrication of nanofibers with desired uniform diameters as potential biomedical materials. This study demonstrated that centrifugal spinning could be an alternative method for the fabrication of uniform nanofibers with high yield.Keywords:carboxylated chitosan;centrifugal spinning;nanofiber diameter;empirical model
研究领域:
生物材料学
·
医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Lunqiang Jin,Haifeng Ji,Yusha Gao,Tao Xu,Shengde Xu,Xiang Zhang,Xiaoling Liu,Feng Liang,Weifeng Zhao,Changsheng Zhao
Developing high-efficiency adsorbents by facile approaches for sewage treatment is high demand but challenging, numerous scientists have made great efforts to fabricate such adsorbents by controlling the structures and functional groups. However, simultaneously improving the adsorption amounts and rates for the microcontaminants seems to be incompatible, which has been puzzling researchers for a long time. To face this challenge, herein, we provided a solution from a strategic perspective instead of only developing a material. We conceived that the key to realize this target was achieving instantaneous diffusion of microcontaminants, and then used regenerative carboxylated sponge ( RCS ) to verify our supposition. As a result, just by simply swelling and squeezing, the sponge could instantaneously clean the positively-charged microcontaminants at a high concentration (1000 μmol/L) and high clearance ratios (the ratios for methylene blue, methyl violet, Cu 2+ , Cr 3+ and Co 2+ were 99.2%, 99.1%, 92.1%, 68.4% and 60.2%, respectively), what’s more, only in one second. Additionally, the sponge could also fulfill large-scaled water purification via suction filtration, and a fast flux of up to 45,000 L/m 3 ·h with ultrahigh clearance ratios (as for positively-charged dyes, the clearance ratios were more than 99%; as for heavy metal ions, the clearance ratios were more than 90%) could be achieved. Additionally, with the advantages of the high adsorption capacity and excellent recyclability, the sponge exhibited long-term purification ability, which might be promising for both small and large-scaled sewage treatment. More importantly, we believed that this strategy might not only be applied in the field of sewage treatment, but also be referenced in the field of bacterial eradication and blood purification, etc.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2024
·Vol. 39
·期 6
·1348-1357
·
IF 1.3
Zhang Xiaoli,Li Tingxue,Wang Qinghua,Yang Yan,Zhang Chenyu,Liu Yaning,Wang Yifeng
On the basis of coordinated electrodeposition of carboxylated chitosan (CCS), we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films. The method shows a range of benefits, such as the convenient and eco-friendly process, mild conditions, and simple post-treatment. The experimental results reveal that a homogeneous deposited film (Cu NCs/CCS nanocomposite film) is generated on the Cu plate (the anode) after electrodeposition, which exhibits an obvious red florescence. The results from TEM observation suggest there are nanoparticles (with the average particle size of 2.3 nm) in the deposited film. Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film. Moreover, the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS, which enables promising application in the electrochemical sensing. By means of fluorescence properties of Cu NCs, the Cu NCs/CCS film also owns the potential in fluorescence detection. Therefore, this work builds a novel method for the green synthesis of Cu NCs, meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.
研究领域:
材料科学
·
生物医学工程
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）