COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
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IF 2.76
Liya Zeng,Yalin Zhang
The principles of formation and stability of nano-emulsions have been extensively investigated in previous research. In this study, we focus on the impact of short-chain alcohols (C < 5) on the formation and stability of oil-in-water nano-emulsions prepared by the spontaneous emulsification method. Due to its smaller droplet size and excellent optical transparency, the nano-emulsion stabilized by Cremophor EL was selected for further study. Addition of alcohol facilitated the nano-emulsion formation, moreover, the droplet size decreased with increasing alcohol chain length (C > 2) and hydroxyl groups. Nevertheless, the droplet size then increased further with the addition of alcohols, which we ascribed to the effect of alcohols on droplet flocculation. An optimum Cremophor EL-to-1-butanol ratio of 2:1 was employed to construct the ternary phase diagram. It was found that the fine droplets (r < 100 nm, PDI < 0.2) were obtained only when converting the initial oil drops completely into the lamellar liquid crystalline phase and/or bicontinuous phase and then this phase became supersaturated in oil, so that the nucleation of oil drops occurred spontaneously. According to the dynamic light scattering results, coalescence and Ostwald ripening were the main destabilization mechanisms in our systems. Notably, nano-emulsion stability was greatly improved with ethanol in comparison to 1-propanol and 1-butanol.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
RSC Advances
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2017
·Vol. 7
·期 32
·19815-19827
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IF 3.108
Liya Zeng,Xin Xin,Yalin Zhang
Nanoemulsions have attracted much attention due to their wide application in commercial industries such as pharmaceutics, food, beverages and skin care. Cremophor EL has been extensively used for emulsification, protection and solubilization of various lipophilic bioactive agents. However, their anaphylactoid hypersensitivity reactions are still challenging. Therefore, the aim of this study was to develop and characterize a promising, low-level Cremophor EL-stabilized o/w nanoemulsion using the spontaneous emulsification method for oral administration. From comparing the physicochemical properties (particle size and size distribution) of their emulsions, Cremophor has better emulsifying capacity than Tween and the droplet radius of emulsions can be reduced by increasing the surfactant concentration in current systems. The impact of various short-chain alcohols (C–OH < 5) on the formation and stability of nanoemulsions was also investigated to optimize the formulations. And there is a good correlation between nanoemulsion droplet size and the surfactant packing parameter (p). The smallest droplet size with the narrowest size distribution was produced by the system containing ethylene glycol as a cosurfactant. However, preparation of nanoemulsions with ethylene glycol was a time-consuming process since it was difficult to emulsify the water-induced gel-structure. Surfactant-to-oil mass ratio and surfactant-to-cosurfactant levels had to be optimized to produce fine droplets. Moreover, there was a linear relationship between the viscosity/log P value of alcohols and droplet size. Ostwald ripening was the dominant breakdown process of nanoemulsions obtained in the ethyl oleate/Cremophor EL–butanol (3 : 2)/water system. Ostwald ripening rate was increased with increasing surfactant concentration. Dilution (100×) of this system considerably improved their stability against droplet growth. This study demonstrated that alcohol addition might be a useful tool for preparing Cremophor EL-stabilized nanoemulsions for pharmaceutical applications.
研究领域:
药剂学
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化学工程
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生物医学工程
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DOI
高影响因子
ACS Catalysis
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2023
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IF 12.9
Shaoxia Guo,Zhuoshi Li,Rui Yin,Jianbao Li,Zhuang Zeng,Zhiwei Hu,Guangyuan Luo,Jing Lv,Shouying Huang,Yue Wang,Xinbin Ma
Higher alcohol synthesis (HAS) from syngas is highly attractive but still challenging due to the complexity of the reaction system and the difficulty in modulating the carbon number distribution of products, especially in improving the selectivity toward ethanol or short-chain alcohols over a single catalyst. Herein, we propose a CoMnOx nanocomposite catalyst with the Co/Mn molar ratio of 1/2 prepared by the facile sol–gel method and found that it could selectively produce short-chain alcohols in the HAS. The C2-5OH proportion in the total alcohol reached 75.5 C%, in which the ethanol proportion was as high as 48.0 C%, breaking through the Anderson-Schulz–Flory distribution and outperforming most of the reported cobalt-based catalysts for HAS. Multiple characterizations and contrast experiments indicated that oxygen vacancies in MnOx that formed during reduction and reaction can dissociate CO but are inactive in C–C coupling, thus generating lots of CHx* monomers. The CHx* intermediates could react with the CO* species adsorbed on the neighboring Co2C species, greatly stimulating the production of ethanol. It is also demonstrated that the oxygen vacancies possibly facilitated the carbonization of cobalt and enhanced the alcohol selectivity, while the untransformed CoxMn1–xO was not active in the reaction. These findings may provide potentials in designing catalysts for highly selective production of ethanol and short-chain products in HAS from syngas.
研究领域:
催化化学
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材料科学
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能源化学
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DOI
高影响因子
ACS Applied Nano Materials
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2025
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IF 5.5
Yingkai Liu,Lei Liu,Yujiang Li,Shaoyu Liu,Weibin Zhang,Ruifeng Zhang,Yao Liu,Qian Rong,Jie Zheng
The regularly ordered core–shell nanorods provide an effective transport channel for the adsorption and desorption of the target molecules. However, it remains a great challenge to precisely control the shell thickness of the ordered core–shell nanorods and improve the catalytic activity of their surfaces due to the complexity of the reaction system, especially by enhancing their selectivity to short-chain alcohols. Herein, we propose ZnO/TiO2 core–shell nanorod arrays (NRs) with different shell thicknesses prepared by electron beam evaporation and found that they possess advanced selectivity for short-chain alcohols. The response time of a ZnO/TiO2 core–shell NR with a TiO2 shell of 30 nm to 100 ppm isoamyl alcohol is 17 s. Its response to 100 ppm of isoamyl alcohol is 807, which is approximately 158 times that of the pure ZnO NR. The ZnO/TiO2 NR (30 nm) sensor exhibited excellent selectivity for methanol, ethanol, isopropanol, n-butanol, and isoamyl alcohol. The response to alcohols increased with the increase of the alcohols’ chain length. Its sensing mechanism for short-chain alcohols is explained in terms of adsorption energy, acidity, and electronegativity of H in organic groups by density functional theory in detail. Our results open an alternative route for the design of sensitive materials for the selective detection of short-chain alcohols.
研究领域:
材料科学
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化学
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DOI
高影响因子
Molecular Catalysis
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2020
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IF 3.687
Yang Zhong,Bo Zhou,Lijun Wang
Fe/FeO x embedded in LDH was prepared by reducing the pre-synthesized [Fe(C 2 O 4 ) 3 ] 3− anions intercalated LDH and used as a multi-functional catalyst for synthesis of C7-C9 compound via transfer hydrogenation between furfural (C5) and short-chain alcohols (C2-C4) and a subsequent aldol reaction of furfural with intermediate short-chain aldehydes in the absence of a homogeneous base with furfuryl alcohol as a byproduct. Screening reaction conditions, evaluation and improvement of the cyclic catalytic performance, and determination of catalytically active components were performed, and the results demonstrated that both high conversion and high selectivity to the C C bond forming product can be obtained under a non-oxidizing atmosphere of Ar or H 2 /Ar mixed gas, a reaction temperature of 140 °C and a reaction time of 4 h; the catalyst was easily deactivated during the cycle experiments, however, its catalytic stability can be effectively improved by depositing Ni with weak reducibility on the surface of Fe nanoparticles at the cost of reducing partial catalytic activity. Fe/FeO x together with LDH as a whole proved to be effective in catalyzing the transfer hydrogenation reaction and the support LDH imparted basic catalytic function to the composite realizing the aldol reaction in the absence of a homogeneous base.
研究领域:
催化化学
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材料科学
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绿色化学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Dazhen Xiong,Qian Zhang,Wenjie Ma,Yang Wang,Wenrui Wan,Yunlei Shi,Jianji Wang
Amino acids are vital compounds in animal and human nutrition. However, it is still a great challenge to develop a cost-effective process for selective separation of amino acids. In the present study, a class of deep eutectic solvents (DESs) with short-chain alkanolamines as hydrogen bond acceptors (HBAs) and phenolic compounds as hydrogen bond donors (HBDs) have been explored for selective separation of aromatic amino acids for the first time. It is found that these DESs exhibit upper critical solution temperature (UCST)-type phase behavior in water, and their phase transition temperature is related with the pK a values of HBAs and HBDs as well as the hydrophobicity of HBDs. The UCST-type phase separation process is investigated by dynamic light scattering (DLS), FT-IR spectroscopy and temperature-variable 1 H NMR in details, and the stability of the DESs in water is also examined. Interestingly, these UCST-type DESs/water systems are applicable to selective separation of aromatic amino acids. The separation factor between L-tryptophan and L-tyrosine as well as between L-tryptophan and L-phenylalanine can reach up to 476.1 and 87.9, respectively, which is about 20 and 19 times that reported in ionic liquids-based extraction solvents.
研究领域:
化学工程
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分析化学
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生物技术
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产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
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2015
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IF 2.184
Sanguo Peng,Shi Zhang,Ying Zhang,Xiangyang Liu,Maogang He
Mutual diffusion coefficients of several short chain alcohols (ethanol, n -propanol and n -butanol) + n -octane mixtures in the temperature range from 283.2 K to 313.2 K at different concentrations were measured using holographic interferometry. The relation between the mutual diffusion coefficient with temperature, viscosity, concentration and molecular weight is investigated, respectively. The Onsager–Fuoss model is applied to analyse the various influence factors. A new correlation taking into account the effect of the temperature and concentration on the mutual diffusion coefficient is proposed to fit well the experimental data.
研究领域:
化学工程
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物理化学
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产品关联
DOI
高影响因子
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