Synthesis of ethyl acetate by esterification of acetic acid with ethanol over a heteropolyacid on montmorillonite K10

In present work,liquid phase esterification of acetic acid with ethanol over dodecatungestophosphoric acid （DTPA） supported on K10 montmorillonite was systematically studied and optimization of process parameters was carried out.The 20% m/m DTPA/K10 was found to be the optimum catalyst with 90% acetic acid conversion and 100% ethyl acetate selectivity.The study was also explored to see the feasibility of 20% m/m DTPA/K10 as a catalyst for the alkylation of acetic acid with other alcohols like methanol,iso-propanol and n-butanol.The 20% m/m DTPA/K10 has shown increased activity with the increase in carbon number,at the same alcohol reflux.The results are novel.

Acetic acid-and furfural-based adaptive evolution of Saccharomyces cerevisiae strains for improving stress tolerance and lignocellulosic ethanol production

Acetic acid and furfural are known as prevalent inhibitors deriving from pretreatment during lignocellulosic ethanol production.They negatively impact cell growth,glucose uptake and ethanol biosynthesis of Saccharomyces cerevisiae strains.Development of industrial S.cerevisiae strains with high tolerance towards these inhibitors is thus critical for efficient lignocellulosic ethanol production.In this study,the acetic acid or furfural tolerance of different S.cerevisiae strains could be significantly enhanced after adaptive evolution via serial cultivation for 40 generations under stress conditions.The acetic acid-based adaptive strain SPSC01-TA9 produced 30.5 g·L^(-1)ethanol with a yield of 0.46 g·g^(-1)in the presence of 9 g·L^(-1)acetic acid,while the acetic acid/furfural-based adaptive strain SPSC01-TAF94 produced more ethanol of 36.2 g·L^(-1)with increased yield up to 0.49 g·g^(-1)in the presence of both 9 g·L^(-1)acetic acid and 4 g·L^(-1)furfural.Significant improvements were also observed during non-detoxified corn stover hydrolysate culture by SPSC01-TAF94,which achieved ethanol production and yield of 29.1 g·L^(-1)and 0.49 g·g^(-1),respectively,the growth and fermentation efficiency of acetic acid/furfural-based adaptive strain in hydrolysate was 95%higher than those of wildtype strains,indicating the acetic acid-and furfural-based adaptive evolution strategy could be an effective approach for improving lignocellulosic ethanol production.The adapted strains developed in this study with enhanced tolerance against acetic acid and furfural could be potentially contribute to economically feasible and sustainable lignocellulosic biorefinery.

Catalytic Esterification of Methyl Alcohol with Acetic Acid

Esterification of methyl alcohol with acetic acid catalysed by Amberlyst-15 (cation-exchange resin) was carried out in a batch reactor in the temperature ranging between 318-338 K, at atmospheric pressure. The reaction rate increased with increase in catalyst concentration and reaction temperature, but decreased with an increase in water concentration. Stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a second-order kinetic model based on homogeneous reaction. The apparent activation energy was found to be 22.9kJ mol-1 for the formation of methyl acetate. The methyl acetate production was carried out as batch and continuous in a packed bed reactive distillation column with high purity methyl acetate produced.

A Comparative Study of Ultrasound-Guided Intratumoral Acetic Acid and Ethanol Injection Therapy for Liver Tumors in Rats

To compare the therapeutic efficacy of USguided intratumoral injection of acetic acid and ethanol in 77 rats with transplanted Walker256 carcinosarcoma. The rats were divided into three groups: intratumoral acetic acid injection (IAI), intratumoral ethanol injection (IEI), and control group receiving intratumoral saline injection (ISI). Tumor growth rates were measured. Pathologic changes were chronologically observed, and tumor necrosis was quantified as a percentage of the tumor volume using a semiquantitative method. Results: Tumor growth rates were -(37±23)% in the IAI group, (210±174)% in the IEI group and (1 303±473)% in the ISI group (P<0.05). Tumor necrosis rates were (97.4±3.7)%, (79.4±10.9)% and (27.2±10.3)% respectively (P<0.01). In addition, the pathologic results showed that necrosis was more complete and repair of the peripheral tissue of tumor was faster in the IAI group as compared with the IEI group. Conclusion: IAI is more effective than IEI in the local therapy for liver tumors.

Production of Bio-gasoline by Co-cracking of Acetic Acid in Bio-oil and Ethanol

Abstract Acetic acid was selected as the model compound representing the carboxylic acids present in bio-oil. This work focuses the co-cracking of acetic acid with ethanol for bio-gasoline production. The influences of reaction temperature and pressure on the conversion of reactants as well as the selectivity and Conaposition of the crudegasoline phase were investigated. It was found that increasing reaction temperature benefited the conversion of reactants and pressurized cracking produced a higher crude gasoline yield. At 400 ℃ and 1 MPa, the conversion of the reactants reached over 99% and the selectivity of the gasoline phase reached 42.79% （by mass）. The gasoline phase shows outstanding quality, with a hydrocarbon content of 100%.

Thermoresistant, Ethanol-Resistant and Acid-Resistant Properties of Acetic Acid Bacteria Isolated from Fermented Mango Alcohol

Vinegar production is seriously affected by the sensitivity of acetic acid bacteria (AAB) to high temperature, high ethanol concentrations, and high acetic acid concentrations. The aim of this study was to investigate the thermo-ethanol-acid tolerance characters of five AAB strains (VMA1, VMA5, VMA7, VMAM, VMAO) previously isolated from fermented mango alcohol and belonging to Gluconoacetobacter genera. As result, the five AAB strains exhibited good growth and acid production at temperatures up to 45°C;they could tolerate and produce acetic acid at ethanol concentrations up to 20% (v/v). In addition, the studied strains showed growth at acetic acid concentrations up to 4.5% (w/v). Strains VMA7 and VMAO showed the highest resistance properties: they demonstrated acid production at 50°C and VMAO could even grow at 60°C;they tolerated and produced acetic acid at 25% (v/v) ethanol concentration;they showed resistance to acetic acid concentrations up to 6% (w/v). Considering all these properties, the use of these strains would seriously contribute to improving the quality of the vinegar produced and help to reduce the cooling water feeds in vinegar production especially in hot countries in the context of global warming.

Towards Biorefinery Production of Microalgal Biofuels and Bioproducts: Production of Acetic Acid from the Fermentation of <i>Chlorella</i>sp. and <i>Tetraselmis suecica</i>Hydrolysates

Successful commercialization of microalgal bio-industry requires the design of an integrated microalgal biorefinery system that facilitates the co-production of biofuels, high-value products and industrial chemicals from the biomass. In this study, we investigated the use of sugar hydrolysate obtained from enzymatic saccharification of microalgal biomass (Chlorella sp. and T. suecica) as fermentation feedstock to produce industrially important chemicals, in particular acetic acid and butyric acid. By using hydrolysate with low sugar content as substrate for the anaerobic fermentation (1.5 - 2.4 g/L), we were able to prevent the bacterium C. saccharoperbutylacetonicum from activating its solventogenesis pathway. As a result, the fermentation process generated a product stream that was dominated by organic acids (acetic acid and butyric acid) rather than solvents (butanol, ethanol and acetone). Acetic acid constituted up to 92 wt% of Chlorella’s fermentation products and 80 wt% of T. suecica’s fermentation products. For T. suecica, the fermentation consumed almost all of the sugar available in the hydrolysate (up to 92% of initial sugar) and produced a reasonable yield of fermentation products (0.08 g fermentation products/g sugar). The Gompertz equation was successfully used to predict the formation kinetics of acetic acid and other fermentation products across both species. The results in the study demonstrate the production of industrially important chemicals, such as acetic acid and butyric acid, from the fermentation of microalgal sugar. The process described in the study can potentially be used as a value-adding step to generate biochemicals from cell debris in an integrated microalgal biorefinery system.

Catalytic upgrading biomass-derived ethanol and acetic acid into C4 chemicals

Synthesis of value-added chemicals from biomass is an essential strategy to mitigate the global dependency on fossil resources and achieve the aim of carbon neutrality. Thereinto, ethanol and acetic acid are crucial biomass-derived platform molecules.Recently, catalytic upgrading ethanol and acetic acid into C4 energy-intensive fuels and chemicals via the elongation of carbon backbone has received widespread attention. The primary focus of this review is to systematically describe the recent breakthrough in the conversion of ethanol or acetic acid to C4 chemicals including 1,3-butadiene, n-butenes, isobutene or n-butanol.Special attentions will be given to heterogeneous catalyst design strategies, reaction parameters on the catalytic performance along with the relevant mechanism investigations, as well as their future challenges and opportunities. The present review will provide the detailed insights into the synthesis of C4 chemicals from biomass-derived ethanol and acetic acid and shed a light on the development of highly efficient catalysts.

Separation of Erucic Acid from Rape-Seed Oil Using Supercritical Carbon Dioxide with Entrainer

Separation of erucic acid from rape-seed oil using supercritical carbon dioxide with entrainer was carried on a pilot column with an inner diameter 14 mm and an effective total height 2.2 m. Experiments were focused on the effects of entrainers, i.e. acetone, ethanol and ethyl acetate, on the extraction. It is showed that entrainers made selectivity lower, but separation time shorter.

A Computational Study on Iridium-Catalyzed Production of Acetic Acid from Ethanol and Water Solution

The mechanism for the production of acetic acid from ethanol and water mixture catalyzed by iridium catalyst has been theoretically investigated.The cooperation of the iridium center and bpyO ligand is highlighted,which plays an important role in the catalytic activity.The hydrogen release from the iridium center is the rate-determining step,with an energy barrier of 22.5 kcal/mol.The electronic structure analysis suggests electron-donating substituents could decrease the energy barrier.

糖醋酒液诱捕核桃园小黄鳃金龟的效果

为研究核桃园中小黄鳃金龟Pseudosymmachia flavescens(Brenske)成虫的发生规律,探讨糖醋酒液对小黄鳃金龟的诱捕效果,本研究采用正交试验筛选糖醋酒液最佳配方,并于2020年-2022年在陕西省商洛市镇安县核桃园开展不同配方糖醋酒液及诱捕器悬挂不同高度诱捕小黄鳃金龟成虫试验。结果表明,糖∶乙酸∶乙醇∶水为3 g∶4 mL∶3 mL∶20 mL的配方对小黄鳃金龟成虫诱捕效果最佳。商洛市镇安县核桃园小黄鳃金龟成虫的发生期为5月上旬至9月中旬,盛发期为6月中旬至7月中旬。糖醋酒液诱捕器在距地面0.5~1.5 m范围内诱捕量随高度升高增加,当高度升至2.0 m时诱捕量明显下降,悬挂高度1.5 m时诱捕量570头/年、占比50.04%,显著高于其他高度处理。糖醋酒液3∶4∶3∶20配方(m∶V∶V∶V)既可准确监测核桃园小黄鳃金龟成虫种群发生动态,亦可高效诱杀用于防治。

适合青梅醋酿造的醋酸菌选育

以腐烂的青梅为筛菌对象,采用平板分离、产酸定性和青梅果醋发酵实验筛选出一株产酸能力强的热带醋酸杆菌(Acetobacter tropicalis)J-27。进一步采用常压室温等离子体(atmosphericand room temperature plasma,ARTP)诱变技术和高通量筛选(high-throughput screening,HTS)相结合的方法,获得了1株具有高耐酸性且酿造后具有典型青梅醋风味的醋酸菌J-2736。用该菌株进行青梅醋发酵实验,发酵结束时总酸质量浓度为62.47 g/L,且菌株对乙醇、乙酸耐受性良好,可以耐受体积分数10%的乙醇和40 g/L的乙酸。对青梅醋中的风味物质进行分析,其中醇类物质、酯类物质和羧酸类物质质量分数较高,分别占挥发性风味物质的11.7%、36.0%和45.9%。因此选育的热带醋酸杆菌J-2736能够较好适应青梅的高酸特性,具有工业应用的可行性。

不同链长烷基酸对纤维素纳米晶的改性研究

为了深入探究不同链长烷基酸对纤维素纳米晶(cellulose nanocrystals,CNC)疏水性以及热性能方面的影响,文中采用乙酸和硬脂酸两种不同链长的烷基酸对CNC进行酯化改性,分别得到乙酰化纳米纤维素(ANC)和硬脂酸改性纳米纤维素(MNC)两种改性产物,并对其疏水性及热性能进行测试表征。研究结果表明:水接触角从28.702°(CNC)分别提高到62.606°(ANC)和64.918°(MNC),改性产物的疏水性都有所提高;但是在热性能方面,ANC由于乙酰基的存在使得其热稳定性提高了47℃;而MNC因为硬脂酸长链烷基分子在高温下不稳定易断裂,所以其最大热分解温度相比CNC降低了34℃,热稳定性有所降低。所以乙酸作为短链烷基酸,既可以在一定程度上提高纤维素纳米晶的疏水性能,又能提高其热稳定性。本文研究结果可为后续与聚乳酸等疏水性聚合物共同制备增强型纳米复合材料提供性能方面的理论依据。

固载质子型离子液体催化酯化反应合成香蕉油——可回收固态催化剂的实验教学应用

酯化反应是大学有机合成实验课程中的重要训练项目。应用溶胶-凝胶法制备了N-甲基咪唑硫酸氢盐固载离子液体催化剂(Meim-HSO_(4)@SiO_(2)),Meim-HSO_(4)@SiO_(2)取代传统无机酸催化醋酸与异戊醇酯化反应。与无机酸相比,固态催化剂Meim-HSO_(4)@SiO_(2)取用更加方便,转化率提高22.1%,反应结束后只需抽滤、洗涤、烘干便可实现催化剂的回收再利用,成本缩减约37.5%。新设计为大学化学教学实验“香蕉油的制备与鉴定”提供了切实可行的催化剂选择新思路,符合绿色化学发展需求,有助于学生综合能力的提升和改进思维的培养。

利用组蛋白H3K9模拟乙酰化提高酿酒酵母对乙酸的耐受性能

随着能源问题日益严峻,将自然界中丰富的可再生资源木质纤维素转化为二代燃料乙醇的设计思路为解决当前的能源危机、粮食危机和环境危机提供了一条出路。然而,微生物在发酵生产二代乙醇的过程中也面临多项技术难题。其中,木质纤维素降解产生的多种小分子化学物质不仅会抑制微生物生长繁殖,同时也会降低微生物的发酵效率。乙酸是多种木质纤维素原料降解物中常见的一种主要抑制剂。为提高微生物的木质纤维素乙醇发酵效率,选取工业生产领域最有潜力的乙醇发酵菌株酿酒酵母为模式生物,通过将组蛋白H3第九位的赖氨酸(K)突变成谷氨酰胺(Q)来模拟组蛋白H3K9的乙酰化状态,以此探究组蛋白H3K9Q点突变体对木质纤维素水解抑制物乙酸的耐受性。点滴平板结果显示,H3K9Q点突变可显著提高酿酒酵母在乙酸条件下的生长性能。生长曲线实验进一步表明,H3K9Q点突变可使菌株在3.5 g/L乙酸胁迫条件下快速进入指数期,由点突变前的36 h缩短为24 h。并且,在添加乙酸的液体培养基中生长48 h后,H3K9Q点突变体的OD _(600)约为对照菌株的1.9倍,说明H3K9Q点突变显著提高了酿酒酵母的乙酸耐受性。本研究为纤维素乙醇工业生产中的菌种优化提供了有益借鉴参考。

Effect of thermal pretreatment on the surface structure of PtSn/SiO2 catalyst and its performance in acetic acid hydrogenation

The effect of thermal pretreatment on the active sites and catalytic performances of PtSn/SiO2 catalyst in acetic acid （AcOH） hydrogenation was investigated in this article. The catalysts were characterized by N2 physical adsorption, X-ray diffraction, transmission electron microscopy, pyridine Fourier-transform infrared spectra, and H2-O2 titration on its physicochemical properties. The results showed that Pt species were formed primarily in crystalline structure and no PtSnx alloy was observed. Meanwhile, with the increment of thermal pretreatrnent temperature, Pt dispersion showed a decreas- ing trend due to the aggregation of Pt particles. Simultaneously, the amount of Lewis acid sites was remarkably influenced by such thermal pretreatment owning to the consequent physicochemical property variation of Sn species. Interestingly, the catalytic activity showed the similar variation trend with that of Lewis acid sites, confirming the important roles of Lewis acid sites in AcOH hydrogenation. Moreover, a balancing effect between exposed Pt and Lewis acid sites was obtained, resulting in the superior catalytic performance in AcOH hydrogenation.

仔猪溃疡性结肠炎模型的建立分析

该研究旨在探索并确立一种可靠的乙酸诱导仔猪溃疡性结肠炎模型。试验选取了18头健康的杜洛克仔猪作为研究对象,将其随机分配至对照组、TNBS组以及乙酸组,每组仔猪麻醉后直肠灌注不同试剂,包括生理盐水、不同浓度的三硝基苯磺酸50%乙醇溶液以及不同浓度的乙酸溶液,旨在诱发不同程度的结肠炎病变。观察期内详细记录仔猪的临床表现与粪便特征,并在灌注3~7 d后进行宰杀,收集结肠组织进行结肠黏膜损伤评估。研究结果指出,直肠灌注10%乙酸能够成功建立仔猪溃疡性结肠炎模型。该研究以期为深入理解溃疡性结肠炎的发病机制、药物筛选及治疗策略提供一个稳定且有效的动物模型平台。

乙酸正丙酯制备条件的优化研究

以乙酸和正丙醇为原料,以浓硫酸为催化剂合成乙酸正丙酯。通过优化催化剂用量、反应温度以及酯化反应时间3个条件,得到了纯度和产率较高的乙酸正丙酯。实验结果表明,当加入催化剂体积为1.5 mL,在100℃下反应时间为50 min时,乙酸正丙酯的精制收率可达到87.8%。

贵金属催化乙醇部分氧化研究进展

综述了近年来贵金属催化乙醇液相氧化的主要研究成果,分析了贵金属种类对乙醇液相氧化反应性能的影响规律,阐明了贵金属的催化机制及影响因素,并深入分析Au元素与载体的相互作用。为乙醇液相氧化反应提供了研究方向。

The cooperation effect of Ni and Pt in the hydrogenation of acetic acid

The catalytic hydrogenation of carboxylic acid to alcohols is one of the important strategies for the conversion of biomass.Herein,a series of Ni-doped PtSn catalysts were prepared,characterized and studied in the hydrogenation of acetic acid.The Ni dopant has a strong interaction with Pt,which promotes the hydrogen adsorption,providing an activated hydrogen-rich environment for the hydrogenation.Meanwhile,the presence of Ni also improves the Pt dispersion,giving more accessible active sites for hydrogen activation.The cooperation of Pt and Ni significantly promotes the catalytic activity of the hydrogenation of acetic acid to ethanol.As a result,the catalyst with 0.1%Ni exhibits the best reaction activity,and its space time yield is twice as that of the PtSn/SiO2 catalyst.It provides a meaningful instruction on the catalyst design for the carboxylic acid hydrogenation.