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1.
《分离科学与技术》2012,47(2-3):373-378
Abstract

The methyl, ethyl, propyl and butyl esters of vegetable and tree oils are effective solvent extractants for 1-butanol from aqueous solution. Early applications of this process will probably involve bacterial mixed solvent fermentations of relatively impure waste and low-valued carbohydrates. Two types of materials, salts and solvents, could be expected to affect the extraction of 1-butanol from such industrial fermentation systems. The effect of four salts, three alcohols, and a ketone were evaluated using factorial experiments. Variations in NaCl, Na2SO4, Na2SO3, and KHPO4 from 0 to 0.15 M on the extraction of 0.1 to 4.1% 1-butanol from aqueous solutions at 25,40, and 55 C gave small changes in distribution coefficient. Mild increases occurred with increasing teperature and increasing NaCl, Na2SO4, and KH2PO4. Mild decreases in 1-butanol extraction occurred with increasing Na2SO3. Variations in acetone, ethanol, and 2-propanol concentrations ranging between 0 and 4% w/v at 25, 40 and 55 C gave small changes in distribution coefficient at 1-butanol concentrations ranging between 0.1 and 4.1% w/v had little effect. A slight increase in 1-butanol extraction was observed with increasing 1-pentanol under similar conditions.  相似文献   

2.
From the electromotive force measurements of the cell Pt (or Pd), H2(g)|HBr(m), 5 wt% alcohol-water mixture|AgBrAg for different m in the temperature range from 288.15 to 308.15 K, the standard potential of AgAgBr electrode has been determined in the mixture where alcohol was 1-butanol and 2-methyl-1-propanol. The standard thermodynamic quantities for cell reaction and for HBr formation, the activity coefficients of HBr, and the standard thermodynamic quantities for the transfer of HBr from water to mixed solvents have been evaluated. The transfer functions were compared with those for water mixtures of other isomeric butanols as well as for the mixture with small proportions of other alcohols.  相似文献   

3.
溶剂对对苯二酚晶体晶习的影响   总被引:3,自引:0,他引:3       下载免费PDF全文
采用冷却结晶方法,考察了水、甲醇、乙醇、正丙醇、异丙醇和正丁醇等溶剂对对苯二酚晶习的影响,并通过扫描电镜、差热扫描分析、X射线衍射等手段对对苯二酚晶体进行了分析表征.结果表明,溶剂性质显著影响对苯二酚晶体的晶习,随着溶剂介电常数的减小,晶体的长径比变小.在利用分子模拟软件Cerius2预测对苯二酚晶体晶习的基础上,初步揭示了溶剂影响对苯二酚晶体晶习的机理.  相似文献   

4.
Solvent extraction technique is one of the cheapest and most efficient processes experienced in recycling of used lubricating oils. In this paper, the performance of three extracting solvents (2-propanol, 1-butanol, and methyl-ethyl-ketone (MEK) in recycling used oil was evaluated experimentally. The effect of the most critical parameters (type of solvent, solvent to oil ratio, and extraction temperature) was investigated. The results show that MEK achieved the best performance with the lowest percent oil losses, followed by 2-propanol and 1-butanol, and as the extraction temperature increases the percent oil losses decreases. The anti-solvency energy (Es), which originates from the solubility parameters difference between the solvent and oil was related to the solvent to oil ratio. It was found that the critical clarifying ratio predicted from such relations for the three solvents reasonably agrees with that measured experimentally. Relations between Es and solvent to oil ratio give a proper guideline for preliminary evaluation of the extracting solvent. It also can be used to predict the optimum solvent:oil ratio and extraction temperature based on the solvent ability to dissolve the base oil in used motor oil.  相似文献   

5.
Polyynes were prepared from pellets of a perylene derivative, 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA), and graphite by liquid-phase laser ablation, using solvents of methanol, ethanol, 1-propanol, 1-butanol, t-butyl alcohol, n-hexane, and decalin. The amounts of polyynes produced from PTCDA strongly depended on the polarity of the solvent, while those from graphite did not. Polar functional groups of acid-anhydride side chains in PTCDA are believed to influence the amounts of C2 radicals produced by laser ablation. The long-chain polyyne C28H2 was detected in a chromatogram of a solution obtained from a graphite pellet and solvent decalin.  相似文献   

6.
The experimental solubility of sulfamonomethoxine in six different pure solvents (methanol,ethanol,1-propanol,l-butanol,ethyl acetate and acetone) and sulfamonomethoxine hydrate in acetone + water mixture solvents were measured from 294.55 K to 362.15 K by a laser dynamic method under atmospheric pressure.Experimental results indicated that the solubility data of sulfamonomethoxine increased with temperature increasing in pure solvents and the solubility followed this order:acetone >methanol > ethanol > ethyl acetate > 1-propanol > 1-butanol,but solubility in ethyl acetate was not affected significantly by temperature.In acetone + water mixture solvent,the solubility of sulfa-monomethoxine hydrate increased with temperature and the acetone concentration.Thermodynamic equations were applied to correlate solubility data of sulfamonomethoxine and sulfamonomethoxine hydrate including the modified Apelblat equation,λh equation,Wilson equation,NRTL equation,Van't Hoff-Jouyban Acree equation and modified Apel-Jouyban-Acree equation.Furthermore,thermodynamic properties △Gd,△Hd and △Sd of sulfamonomethoxine and sulfamonomethoxine hydrate in dissolution process were obtained and discussed with the modified Van't Hoff equation and Gibbs equation.  相似文献   

7.
将两种不同极性的有机溶剂1,4-二氧六环和正庚烷按不同摩尔比混合,配成具有不同logP值的双组分混合溶剂,以此为反应介质考察了固定化脂肪酶Lipozyme RM IM催化的正丁醇和月桂酸酯化反应的初速度. 同时在与上述混合溶剂具有相近logP值的单一溶剂中进行了类似研究. 实验结果表明,在混合溶剂和单一溶剂中,反应初速度随溶剂极性的变化规律呈现很大差异. 从溶剂混合对反应物热力学活度及反应活化能的影响可以合理地解释这一实验结果.  相似文献   

8.
A simple solvothermal low‐temperature synthesis process of TiO2 nanoparticles was investigated in different solvents [Octanol (Oc), Ethanolamine (Am) and Terathane (Tr)] with titanium (IV) chloride (TiCl4) as precursor. The samples were characterized by X‐Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). XRD showed the crystallite size ranging from 4 to 12 nm, which were calculated using Debye–Scherrer's equation. The existence of poor or high crystalline anatase phases and high crystalline anatase/rutile mixture was also shown. TEM images displayed variations in the morphological behavior depending on the synthesis condition. Particles of irregular morphology with high irregular agglomeration up to well‐defined particles can be observed, which are self‐assembled by oriented attachment (OA). This self‐assembly led to TiO2 microparticles with 3‐D Wulff shape for anatase and 1‐D shape for rutile. The results showed that the TiO2 nanopowder could be easily engineered and adapted by the solvent type, the TiCl4 concentration and the synthesis time.  相似文献   

9.
Well‐dispersed hollow TiO2 spheres were synthesized via Ostwald ripening through a fluorine‐free solvothermal process in a n‐PrOH/H2O mixed solvent. Several commonly used acids, such as HNO3, HCl, and H2SO4, were found to be effective as the ripening‐directing agent to replace the highly corrosive HF, and the hollow TiO2 sphere size could be modulated by varying the reactant concentrations. The effects of the solvents and reactants were explored in details, which demonstrated that four important criteria existed in this fluorine‐free process to create well‐dispersed hollow TiO2 spheres, including the utilization of n‐PrOH/H2O mixed solvent, certain degree of acidity, coexistence of different acids, and the existence of SO42? in the reaction solution. After calcination for a better crystallization, these hollow TiO2 spheres were composed of pure anatase phase, and had a good photocatalytic degradation performance on RhB under UV illumination.  相似文献   

10.
ZrO2–SiO2 mixed xerogel and aerogel samples with varied molar ratios were prepared by sol–gel method followed by oven drying and supercritical drying using n-propanol as a solvent, respectively. Sulfation was carried out to further enhance the acidic properties of the mixed oxides. Effect of drying, Zr/Si molar ratio and sulfation have been studied and correlated with the structural, textural and catalytic properties of ZrO2–SiO2 mixed oxides. Both xerogel and aerogel mixed oxides have different structural and textural features, however, the total number of acid sites per unit surface area (0.0021–0.0029 mmol NH3 m−2) and thus the catalytic activity for cyclohexanol conversion (31–41%) was found in the similar range. Sulfated mixed oxide aerogel and xerogel samples showed significant enhancement of cyclohexanol conversion (91–99%).  相似文献   

11.
The emf of the cell: Cu|Cu2+ in water||Cu2+ in water + alcohol|Cu for different alcohols (methanol, ethanol, 1-propanol, 2-propanol, t-butanol, ethylene glycol, propylene glycol and glycerol) and their mixtures with water have been measured at 25°C. These data were used for calculation of Gibbs free energies of transfer of copper(II) ion from water to nonaqueous alcohols and to their mixtures with water, with the help of negligible liquid junction potential assumption. Determined free energies of transfer are positive for all solvents studied, which may be simply interpreted assuming that copper(II)ion interacts more strongly with water molecules than with alcohol molecules, without reference to any special structural properties of these solvents.  相似文献   

12.
Phase transition was observed in HSMA/PVA IPN gels having ionizable groups with 3-dimensional network structure in the mixed solvents such as water-methanol. water-acetone or water-ethanol. In order to analyze this phenomena quantitatively, two adjustable parameters related to gel properties were determined from the model based on Tanaka theory. One was the number of dissociated counterions per effective chain (f). the other was the interaction parameters (xjj) between gel and water. As increasing the composition of water, swelling of the gels occurs in the mixed solvent; the gel was shrunk instead when the water content was decreased, which was reversible regardless of the path of swelling and shrinking. A degree of swelling or shrinking of the gel was dependent upon theseX ijand f of the gel. With smallerX n and larger f. more rapid phase transition was observed. Additionally, swelling and shrinking behavior of the gel in system of two solvents and one polymer was influenced not only byx ij between gel and solvents but also by xij between two solvents.  相似文献   

13.
The effect of structure of substrates and solvents on the process of competitive hydrogenation of binary mixtures of olefinic substrates in the liquid state on 5% Pt/SiO2 catalyst has been investigated. The hydrogenations were carried out at 20°C under atmospheric pressure of hydrogen in the absence of solvent, in methanol and in cyclohexane; one series was also performed in sec-butanol and in tert-butanol. Selectivity changed markedly owing to the different adsorptivity of the substrates. In more polar solvents hydrogenation of less polar substates was relatively preferred.  相似文献   

14.
In this work, the BaF2 nanopowders with different particle size were synthesized by precipitation in the ethanol/water mixed solvents. Five kinds of compositions of mixed solvents, including pure water, 25 vol.%, 50 vol.%, 67.5 vol.%, and 75 vol.% of ethanol were used. The effects of aging and the volume percentage of ethanol in the mixed solvents on the resultant BaF2 nanoparticles were under investigation. The size and morphology of the BaF2 particles were characterized by TEM, FSEM and XRD analyses. The results show that after aging for 2 h the particle size of the BaF2 precipitates in the 50% mixed suspension changes little. The prepared BaF2 particles all exhibit cubic fluorite structures no matter what kind of composition is used. In pure water environment, the size of BaF2 particles is about 70 nm, whereas it reduces to 33 nm in the 75% mixed solution. As the vol.% of ethanol increases the particle size decreases, and other properties such as the size distribution, dispersion, oriented growth et al. are also modulated. These alterations can be interpreted by varying the dielectric constant of mixed solvent.  相似文献   

15.
We report the synthesis, morphology, and photophysical properties of poly[2,7-(9,9-dihexylfluorene)]-block-poly[3-(trimethoxysilyl)propyl methacrylate] (PF-b-PTMSPMA) with two different coil lengths. Ethyl acetate (EA) and methanol (MeOH) are used as selective solvents for the PF rod and PTMSPMA coil blocks, respectively, while THF as the common solvent. Micelle morphologies of the PF-b-PTMSPMA in THF/MeOH or THF/EA mixed solvents are characterized by transmission electron microscopy (TEM) and scanning force microscopy (SFM). In the THF/MeOH mixed solvent, PF-b-PTMSPMA assembles into diverse morphologies of sphere, short cylinder, cylinder, and cylinder bundles. Besides the selective effects, the strong π–π interaction of PF contributes partially to the above morphologies. In the THF/EA mixed solvent, morphologies of the PF-b-PTMSPMA changes from large compound micelles (LCM) to hollow spherical micelles due to the strong core chain stretching. Stable micelles are obtained by crosslink Si(OR)3 groups of the PTMSPMA block by triethylamine (TEA). The micellar morphology significantly affects the photophysical properties. In the THF/MeOH mixed solvent, blue shifts on the UV-vis and fluorescence spectra are observed probably attributed to the formation of the H-aggregation in the PF core. However, the photophysical properties are insensitive to the different ratios of THF/EA, due to the insignificant aggregation of short PF corona. The present study reveals that the morphology and photophysical properties of fluorene-based rod-coil polymers could be significantly manipulated through solvent, rod/coil ratio, and π–π interaction.  相似文献   

16.
Titania powders were synthesized by the thermal hydrolysis of titanium tetrachloride with the yield of above 85% in a mixed solvent of n -propanol and water. The morphology of the precipitates was controlled by adjusting the volume ratio of n -propanol to water (RH ratio) of the mixed solvent. Precipitates obtained with an RH ratio of 0 were fine, and highly agglomerated. In contrast, an RH ratio of 3 resulted in precipitates consisting of uniform and discrete particles. According to observations of the zeta potentials of precipitates and the dielectric constants of solvents, the discrete particles obtained with an RH ratio of 3 resulted from the low zeta potential and dielectric constant. The result of Fourier transform infrared (FTIR) spectroscopy showed the chemical interaction of particle surface with the solvent alcohol, which decreased the zeta potential of precipitates with an increase of RH ratio. Adding hydroxypropyl cellulose (HPC) as a steric dispersant made it possible to reduce the size of particles to the submicrometer range. Effects of the solvent on the formation and morphology of the resulting particles were investigated.  相似文献   

17.
《分离科学与技术》2012,47(12):2391-2410
Abstract

The selective extraction of sulfate and chloride ions from mixed solvent solutions was investigated. The mixed solvents consisted of water and 50 to 100%‐w (salt‐free solvent) ethylene glycol. The extraction was measured for mixed solvent solutions containing only sulfate and chloride, and mixed solvent solutions saturated with trona (sodium sesquicarbonate, Na2CO3 · NaHCO3 · 2H2O(s). Three anion exchange resins, Dowex 1X8‐50, Dowex 21K‐Cl, and Dowex MSA‐1, were investigated for their chemical and physical resistance to the mixed solvent carbonate/bicarbonate solutions, for their swelling behavior in the different mixed solvents, and for their extraction efficiency for chloride and sulfate.

The loading of the ion exchangers was fitted to a Langmuir‐type sorption model. While the extraction from trona‐free mixed solvents was well reproduced, the loading of the ion exchangers with chloride and sulfate from trona‐saturated mixed solvent solutions did not fit the sorption model. It appears, rather, that under these conditions chloride and sulfate are “salted out” of the bulk solution and driven into the ion exchangers.  相似文献   

18.
Limiting viscosity numbers ([ν]) and Schulz-Blaschke constants (ks) of PMMA samples (differing in molecular weight) have been determined at 25°C (as a function of mixed solvent composition) for the following mixtures: acetonitrile+1-butanol, acetonitrile+pentyl acetate, and 1-chlorobutane+pentyl acetate. The first two mixtures are powerful cosolvents of PMMA and the third one is a ‘co-nonsolvent’ of the polymer. The samples are predominantly heterotactic. Their ks values at θ indicate some association tendency of the polymer. Unperturbed dimensions and coil expansion coefficients have been obtained from [ν], as a function of solvent mixture composition. All the pure liquids are poor or non-solvents of PMMA (at 25°C), but the cosolvent pairs behave as very good solvents for the polymer. The mechanism of such cosolvency is analysed in terms of the different molecular interactions present in these systems.  相似文献   

19.
With the increasing concern about the depletion of fossil reserves and greenhouse gas emissions, it is desired to replace coatings which are made using petrochemical-based materials with renewable alternatives such as bio-based polymers. In this paper, fully bio-based thermosets for coatings were prepared from epoxidized sucrose soyate derived from sucrose and soybean oil fatty acid along with citric and malic acids found naturally in juices with the assistance of different solvents. The solvents with reasonable boiling point and good miscibility with citric acid and malic acid, such as water, ethanol, 1-propanol, 2-propanol, and 1,4-dioxane, were screened and used to investigate their effects on the curing and properties of the fully bio-based thermosets. The curing reactivity was studied by examining the gel time and nonisothermal curing process with DSC. The thermal and mechanical properties as well as coating performance properties were also investigated.  相似文献   

20.
The dispersion of graphite oxide (GO) in organic solvents followed by their evaporation at relative high temperature resulted in a strong adsorption of the solvent molecules in the graphitic interlayers as confirmed by 13C magic-angle-spinning NMR. Three series of solvents, alcohols (1-methanol, 1-propanol, 1-pentanol, 1-heptanol), aromatics (benzene, toluene, p-xylene, chlorobenzene) and chloride compounds (dichloromethane, chloroform, carbon tetrachloride) were studied to understand the interaction of graphite oxide with solvents. The distribution of basal interlayer spacing changed due to solvent intercalation and this distribution was particularly different for each solvent series. Even though there was on average 1 solvent molecule per 100 carbon atoms of GO, they had a profound effect on the thermal properties of the resulting GO. The exfoliation temperature was drastically reduced by the presence of the solvents due to the increase of the interlayer spacing and the reducing power of the solvent.  相似文献   

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