MOLECULAR CRYSTALS AND LIQUID CRYSTALS
·
2020
·
IF 0.512
Gege Jin,Yongmin Guo,Limin Wu,Yi Li,Baozong Li,Yonggang Yang
Three series of meta-perfluoroalkylphenol esters are synthesized. Both SmA and SmC phases are identified. Their clearing points increase with increasing the perfluorocarbon chain length, while decrease with increasing the alkoxy chain length. Comparison of the 3-tridecafluorohexylbenzoates and 3-tridecafluorohexylphenol esters, the 3-tridecafluorohexylbenzoates show higher clearing points, indicating that the direction of the ester bond plays an important role in the thermostability of the liquid crystalline phases. Moreover, it was proposed that the compounds with short and long alkoxy chains packed into different structures.
研究领域:
材料化学
·
分子结构研究
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2021
·
IF 3.512
Yongdong Liu,Yonghong Wu,Jianqi Yao,Jiajie Yin,Jing Lu,Jie Mao,Min Yao,Faliang Luo
To explore the effects of end groups on the confined crystallization of an alkyl chain, 3-pentadecylphenol (PDP) was infiltrated into the anodic aluminum oxide template (AAO) to investigate the melting and crystallization behaviors of PDP in a nanoconfined environment. Wide-angle X-ray diffraction (WAXD) found that the solid–solid phase transition of PDP occurred under confined conditions, and the absence of the (00L) reflections indicated that the stacking of the end groups of the alkyl chain layered structure was seriously disturbed. Thermal analysis (TG) showed that the thermal stability of the confined samples decreased due to the confinement effect, and the introduction of end groups made the confinement effect more obvious. Differential scanning calorimeter (DSC) results well reflected the space–time equivalence in the PDP crystallization processes, i.e., the solid–solid phase transition can be achieved by reducing the cooling rate or confining PDP in the nanometer space. Compared with C15, the introduction of the end groups with a phenol ring led to the disappearance of the solid–solid phase transition of an alkyl chain at high cooling rates. In the confined environment, the introduction of the end groups with a phenol ring caused the melting double peaks of the alkyl chain to become a single melting peak, and it also caused the disappearance of the surface freezing monolayer for alkyl chains. Through the analysis of crystallinity, it was found that AAO-PDP was more sensitive to AAO pore size changes than AAO-C15, the Xc of AAO-PDP had a good linear relationship with the pore size d, but the Xc of the AAO-C15 had a nonlinear relationship with the pore size d. Attenuated total reflection (ATR)-IR proved that in the confined environment, the order of the alkyl chain decreased and the degree of chain distortion increased.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Daoming Chen,Han Xu,Lifeng Li,Tao Ruan,Xinping Ouyang,Xueqing Qiu
The hydrodemethoxylation (HDMO) of lignin-derived monophenolics to alkylphenols is a crucial step for the conversion of lignin bio-oil into chemicals. A new FeNi 3 alloy catalyst was firstly prepared by being reduced in-suit from Fe, Ni oxides precursor. The FeNi 3 /FeNi 8 O 9.25 catalyst prepared using optimal 12:88 of molar ratio of iron nitrate to nickel nitrate showed good catalytic activity and selectivity to HDMO of lignin-derived monophenolics. In the HDMO process of lignin-derived 4-propylguaiacol, FeNi 3 /FeNi 8 O 9.25 contributed to a 94.53 % of conversion and a 90.67 % of demethoxylation selectivity under 0.4 MPa H 2 at 280 °C for 2 h. Compared with the Ni/Ni 1 O catalyst, the FeNi 3 /FeNi 8 O 9.25 catalyst increased by 6.19 times and 2.35 times of the specific surface area and total acid amount, respectively. FeNi 3 (111) possessed lower adsorption energy to substrate and changed adsorption configuration of the benzene ring in tilted mode. Consequently, prepared catalyst facilitated the removal of methoxy group, as well as suppressing hydrogenation saturation of the benzene ring. Moreover, FeNi 3 /FeNi 8 O 9.25 catalyst exhibited versatile capacity of HDMO to different lignin-derived monophenolics and high stability. This work offers a new strategy for constructing non-noble metallic alloy catalyst for highly selective HDMO reactions.
研究领域:
催化化学
·
生物质转化
·
绿色化学
·
能源化工
·
有机反应工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2015
·Vol. 6
·期 21
·3926-3933
·
IF 5.52
Shanshan Liu,Qibin Chen,Yujie Sheng,Jincheng Shen,Changjun Peng,Honglai Liu
Developing supramolecular helical assemblies with a controlled helix sense and revealing the forming mechanism of hierarchical helices for mimicking biological self-organization and physiological processes remain major challenges. In this work, a bottlebrush-like supramolecular polymer is prepared through the formation of a hydrogen bond between the keto group of polyvinylpyrrolidone (PVP) and the phenolic hydroxyl group of p-dodecylphenol (PDP), characterized by 1H NMR and FT-IR spectroscopy. CD spectra show an unsplit Cotton effect, suggesting the emergence of a helical structure in this supramolecular polymer brush (PVP–PDP). In particular, straightforward experimental evidence for the formation of hierarchical helices is obtained via TEM and AFM methods. We propose a detailed structural transition of the hierarchical helix or superhelix of PVP–PDP from primary to secondary, tertiary and even quaternary structures, resulting from the incorporation of bulky pendant PDP into the PVP backbone and the binding site of the hydrogen bond at ortho-position.
研究领域:
超分子化学
·
高分子科学
·
材料科学
·
纳米技术
·
生物物理学
✓ 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）