脂肪酸甲酯在甲酸自催化体系中的环氧化和开环反应动力学研究

环氧脂肪酸甲酯是一种性能优良的塑料增塑剂,研究了环氧脂肪酸甲酯合成过程中脂肪酸甲酯在甲酸自催化体系中的环氧化和开环反应动力学。在环氧化反应中,双键和过氧甲酸的反应级数分别为1．43级和1级,反应活化能为56．3kJ／mol;在环氧基团的开环反应中,水对开环反应的作用非常微弱,体系中甲酸对开环反应起主导作用;实验得到在环氧基团和甲酸的开环反应中,环氧基团和甲酸的反应级数分别为1级和1．85级,反应活化能为94．7kJ／mol。     

鼓泡反应器中仿生催化环己烯环氧化的动力学研究

研究针对仿生催化环己烯环氧化工艺,从气液反应传质强化出发,进行了鼓泡反应器中的环己烯环氧化动力学研究。研究得出,环己烯的反应级数为1.0,活化能为54.58kJ/mol,指前因子为1.8×10⁵ s^-1。异丁醛的反应级数为1.5,活化能为28.5kJ/mol,指前因子为9.2×10³ s^-1,2-环己烯醇的生成速率为1.0×10^-4mol/(L·min),2-环己烯酮生成速率为3.0×10^-4mol/(L·min),2种副产物反应级数均为0级。反应动力学符合米氏方程。     

聚氨酯用高羟值大豆油多元醇的合成与表征

本文以大豆油为原料,采用过氧甲酸氧化法制备了高环氧值环氧大豆油(ESO);以氢氧化锂为催化剂,并通过三羟甲基丙烷对其开环合成了高羟值的大豆油多元醇(TESO),研究了反应温度、反应时间对反应进程的影响。用傅里叶红外光谱及1HNMR对其进行表征,结果表明在在190℃下反应4h可以得到高羟基的大豆油多元醇。     

环氧大豆油与聚乳酸的反应及动力学分析

对环氧大豆油与乳酸低聚物的熔融聚合进行研究.采用乌氏黏度计检测反应产物的特性黏度.并且利用化学滴定法检测扩链产物中端羧基的剩余含量,分析反应的动力学.结果显示:质量百分比为8%的环氧大豆油和乳酸低聚物反应产物的特性黏度可以达到1.0以上.环氧大豆油与乳酸的熔融反应对于环氧大豆油与乳酸低聚物的反应级数分别为1级和0.5级.     

阳离子交换树脂催化合成甲酸异丁酯的动力学研究

以NKC-9强酸性阳离子交换树脂为催化剂,在间歇反应装置中,研究了甲酸和异丁醇酯化合成甲酸异丁酯的动力学过程。实验中采用控制变量法,考察了外扩散、催化剂用量、反应温度和反应初始醇酸比等条件对甲酸反应速率及平衡转化率的影响,并测定不同条件下甲酸异丁酯合成反应动力学数据。采用拟均相模型对所得动力学实验数据进行了关联,建立并验证了甲酸异丁酯合成反应的动力学模型,获得平衡常数、反应热和反应速率常数等相关反应动力学参数。结果表明,在一定范围内,增大催化剂用量、反应温度和反应初始醇酸比有助于提高反应速率。该反应为吸热反应,反应热为3.6407 kJ/mol,正反应活化能为37.5735 kJ/mol,逆反应活化能为33.9319 kJ/mol。经验证,拟均相反应动力学模型可准确描述甲酸与异丁醇酯化反应动力学过程。     

由硫酸铝催化合成环氧大豆油

以硫酸铝作催化剂催化合成环氧大豆油方法可行，反应活性高，比硫酸催化法后处理容易，比阳离子交换树脂催化法成本低。实验投料比为大豆油：双氧水：甲酸：硫酸铝＝１：０．２７～０．２９：０．１２～０．１５：０．１～０．０８，过氧甲酸环氧化温度３５℃，环氧化收率９６％，环氧大豆油产品环氧值６．１７～６．２０％，酸值０．４４～０．４８ｍｇＫＯＨ／ｇ。     

不同植物油脂在近临界水中水解反应动力学的比较

系统地测定了压力10 MPa、温度170℃～240℃范围内橄榄油、花生油、大豆油、红花油等植物油脂在近临界水中无催化水解反应动力学数据。实验结果表明,近临界水中油脂水解反应是一个典型的自催化反应,采用二级自催化反应动力学模型对动力学数据进行了拟合,得到了橄榄油、花生油、大豆油、红花油等四种植物油脂的水解反应活化能分别为41.8 kJ/mol、37.3 kJ/mol、37.7 kJ/mol、31.2 kJ/mol。油脂水解活化能与其碘价密切相关,随着油脂碘价的增加,水解活化能逐渐降低。     

无溶剂法合成环氧大豆油新工艺的研究

叙述了无溶剂法合成环氧大豆油的方法，主要反应条件对环氧化反应的影响，并对溶剂法合成环氧大豆油与无溶剂法合成环氧大豆油的技术路线，工艺流程、工艺条件以及产品质量进行了比较     

无硫酸环境环氧化大豆油合成条件优化

在无溶剂无硫酸条件下合成了环氧大豆油,对环氧化合成体系中的羧酸类型、用量及双氧水浓度等影响环氧值的若干因素进行了研究。甲酸的环氧化活性比乙酸和丙烯酸高。通过正交实验确定了最佳合成工艺条件为:m(大豆油)m(甲酸)m(双氧水)为1 0.15 1.0,反应温度60℃,反应时间5～6 h。产品环氧值≥6.20%,残留碘值<6.0%。产品经红外分析表明,在3008 cm-1处的原料C=C双键结构峰消失,在820 cm-1、787 cm-1处呈现出环氧键的伸缩振动的特征吸收峰。     

微量硫酸催化环氧大豆油的合成

在无溶剂条件下,以甲酸为载氧体合成了环氧大豆油. 通过正交实验确定了甲酸自催化合成环氧大豆油的优化工艺条件. 为进一步提高环氧值和缩短反应时间,添加微量硫酸作为催化剂,并优化了其用量. 结果表明,当大豆油、88%甲酸、30%双氧水和硫酸的质量比为1:0.13:0.7:0.004时,在65℃下反应3 h,产品的环氧值为6.2%,残留碘值<6.0%. 采用红外光谱和核磁共振对产品进行了表征.     

Studies on the kinetics of in situ epoxidation of vegetable oils

In the present work, the kinetics of the epoxidation of soybean oil (SBO) by peroxyacetic acid (PAA) generated in situ in the presence of sulfuric acid as the catalyst was studied at various temperatures (45, 65 and 75 °C). It was found that epoxidation with almost complete conversion of unsaturated carbon and negligible oxirane cleavage can be attained by the in situ technique. The rate constant for epoxidation of SBO was found to be of the order of 10^–6 mol^–1s^–1 and the activation energy of epoxidation is 43.11 kJ/mol. Some thermodynamic parameters: enthalpy, entropy and free activation energy of 40.63 kJ/mol, –208.80 J/mol and 102.88 kJ/mol, respectively, were obtained for the epoxidation of SBO. The kinetic and thermodynamic parameters of epoxidation obtained from this study indicate that an increase in the process temperature would increase the rate of epoxide formation. The epoxidation of corn oil and sunflower oil were also investigated under the same conditions. The results show that the reaction rate is in the order of soybean oil > corn oil > sunflower oil.     

环氧低热油的制备及其增塑性能

选用常用来合成环氧大豆油和环氧脂肪酸甲酯的大豆油为原料,运用GC-MS联用仪测定了其组成及含量,并通过酯交换、环氧化等工艺合成了具有环氧结构的环氧长短链酰基甘油酯（环氧低热油）;并对其作为聚氯乙烯增塑剂的各项性能进行了研究。结果表明,大豆油不饱和脂肪酸含量达88.5%,当其与三乙酸甘油酯在物质的量之比为1∶1的情况下可得到以二脂肪酸单乙酸酯为主要成分的低热油;此外,通过物化性能、动态热机械分析、薄膜拉伸、热重-红外-质谱及热分解动力学等手段分析,结果表明环氧低热油的玻璃化转变温度为–0.77℃,低于环氧大豆油的6.13℃;其断裂伸长率为370.56%,也高于环氧大豆油321.11%;与环氧脂肪酸甲酯相比具有更高的闪点、较少的加热减量和更优良的热稳定性。所以环氧低热油是一种较为优良的增塑剂产品。     

Oxirane Cleavage Kinetics of Epoxidized Soybean Oil by Water and UV‐Polymerized Resin Adhesion Properties

Di‐hydroxylated soybean oil (DSO), a biobased polyol synthesized from epoxidized soybean oil (ESO) could be used to formulate resins for adhesives; however, current DSO synthesis requires harsh reaction conditions that significantly increase both cost and waste generation. In this paper, we investigate the kinetics of oxirane cleavage in ESO to DSO by water and elucidate the role of different process parameters in the reaction rate and optimization of reaction conditions. Our kinetic study showed that ESO oxirane cleavage was a first‐order reaction and that the ESO oxirane cleavage rate was greatly influenced by tetrahydrofuran (THF)/ESO ratio, H₂O/ESO ratio, catalyst content, and temperature. Optimized reaction parameters were THF/ESO of 0.5, H₂O/ESO of 0.25, catalyst content of 1.5 %, and reaction time of 3 h at 25 °C. DSO with hydroxyl value of 242 mg KOH/g was obtained under these conditions. We also characterized the structure, thermal properties, adhesion performance, and viscoelasticity of UV‐polymerized resins based on this DSO. The resin tape exhibited peel adhesion strength of 3.6 N/in., which is comparable to some commercial tapes measured under similar conditions.     

Epoxidation of soybean oil in toluene with peroxoacetic and peroxoformic acids — kinetics and side reactions

The kinetics of the epoxidation of soybean oil and the extent of side reactions were studied at 40, 60, and 80 °C. Epoxidation was carried out in toluene with “in situ” formed peroxoacetic and peroxoformic acid and in the presence of an ion exchange resin as the catalyst. The reaction was found to be first‐order with respect to the double bond concentration. At higher temperatures and at higher conversions a deviation from the first‐order kinetics was observed. The rate constants for the epoxidation with peroxoacetic acid were 0.118 (h⁻¹) at 40 °C, 0.451 (h⁻¹) at 60 °C and 1.278 (h⁻¹) at 80 °C, while those for peroxoformic acid were 0.264, 0.734, and 1.250 (h⁻¹). The activation energy was found to be 54.7 kJ/mol for the epoxidation with peroxoacetic acid and 35.9 kJ/mol for that with peroxoformic acid. Three factors indicated that side reactions did not occur on a large scale: The absence of an OH band in the IR spectra, the formation of less than 2% of higher molecular weight products from gel permeation chromatography and the selectivity values between 0.9 and 1.     

Curing kinetics of bio‐based epoxy resin based on epoxidized soybean oil and green curing agent

New thermoset with a high bio‐based content was synthesized by curing epoxidized soybean oil (ESO) with a green curing agent maleopimaric acid catalyzed by 2‐ethly‐4‐methylimidazole. Non‐isothermal differential scanning calorimetry and a relatively new integral isoconversional method were used to analyze the curing kinetic behaviors and determine the activation energy (E_a). The two‐parameter ?esták–Berggren autocatalytic model was applied in the mathematical modeling to obtain the reaction orders and the pro‐exponential factor. For anhydride/epoxy group molar ratio equal to 0.7, E_a decreased from 82.70 to 80.17 kJ/mol when increasing the amount of catalyst from 0.5 to 1.5 phr toward ESO. The reaction orders m and n were 0.4148 and 1.109, respectively. The predicted non‐isothermal curing rates of ?esták–Berggren model matched perfectly with the experimental data. © 2016 American Institute of Chemical Engineers AIChE J, 63: 147–153, 2017     

Kinetic Studies on Oxirane Cleavage of Epoxidized Soybean Oil by Methanol and Characterization of Polyols

The kinetics of the oxirane cleavage of epoxidized soybean oil (ESO) by methanol (Me) without a catalyst was studied at 50, 60, 65, 70 °C. The rate of oxirane ring opening is given by k[Ep][Me]², where [Ep] and [Me] are the concentrations of oxiranes in ESO and methanol, respectively and k is a rate constant. From the temperature dependence of the kinetics thermodynamic parameters such as enthalpy (ΔH), entropy (ΔS), free energy of activation (ΔF) and activation energy (ΔE _a) were found to be 76.08 (±1.06) kJ mol⁻¹, −118.42 (±3.12) J mol⁻¹ k⁻¹, 111.39 (±2.86) kJ mol⁻¹, and 78.56 (±1.63) kJ mol⁻¹, respectively. The methoxylated polyols formed from the oxirane cleavage reaction , were liquid at room temperature and had three low temperature melting peaks. The results of chemical analysis via titration for residual oxiranes in the reaction system showed good agreement with IR spectroscopy especially the disappearance of epoxy groups at 825, 843 cm⁻¹ and the emergence of hydroxy groups at the OH characteristic absorption peak from 3,100 to 3,800 cm⁻¹.     

Effect of functionality and content of epoxidized soybean oil on the physical properties of a modified diglycidyl ether of bisphenol A resin system

Partially epoxidized soybean oil (pESO) and fully epoxidized soybean oil (fESO) were used respectively to modify a diglycidyl ether of bisphenol A (DGEBA) resin system in this study. The pESO was prepared by epoxidizing soybean oil and the fESO was purchased as it was commercially available. DGEBA/ESO ratio of the epoxy resin system was changed from 100/0 to 70/30 and triethylenetetramine was used as a curing agent. Impact strength of the bio-epoxy resin system with fESO increased with ESO content, but the system with pESO decreased with ESO content. The bio-epoxy resin system with pESO showed higher tensile strength and elongation at break than the system with fESO at ESO 30 wt%. Tensile modulus and thermal degradation temperature decreased with ESO content and glass transition temperature was highest at 20 wt% ESO regardless of epoxide functionality of ESO. The performance of the DGEBA/ESO bio-epoxy resin system could be tailored by changing ESO content and functionality.     

反应条件对环氧大豆油酯化反应的影响研究

通过调节温度、投料比、投料方式、催化剂、阻聚剂用量等条件,合成了一系列环氧大豆油丙烯酸酯低聚物。采用紫外光固化制备固化膜,并测定了固化膜的凝胶含量。实验结果表明,产物的酯化程度随着反应温度的升高而增大,但过高的温度增加了产物的黏度。适当提高体系中环氧大豆油含量,改变投料方式,合适的催化剂和阻聚剂用量,有利于提高合成产物的酯化程度。最终得出反应温度120℃、n(环氧大豆油)∶n(丙烯酸)=1.12∶1、将环氧大豆油与阻聚剂预先混合,再滴加丙烯酸与催化剂的混合物的投料方式、w(阻聚剂)=0.15%,为最佳反应条件。     

羟乙基纤维素接枝环氧大豆油高分子表面活性剂的合成及性能

以羟乙基纤维素(HEC)与环氧大豆油(ESO)为原料,四氯化锡(Sn Cl4)为催化剂,二甲亚砜(DMSO)为溶剂,在室温下反应制备了羟乙基纤维素接枝环氧大豆油(ESO-HEC);ESO-HEC经碱性水解后,用酸处理得到羟乙基纤维素接枝环氧大豆油水解的酸性产物(H-ESO-HEC);再通过Na OH中和H-ESO-HEC结构中的羧酸基团,得到3种HESO-HEC-Na高分子表面活性剂。通过FT-IR表征了3种表面活性剂酸性产物H-ESO-HEC的结构;热重测试表明H-ESO-HEC比HEC具有更好的热稳定性;动态表面张力测试表明当H-ESO-HEC-Na的质量浓度升高,动态表面张力下降,且质量浓度达到临界胶束浓度时,最小表面张力值可达29 m N/m;泡沫性能测试表明随着ESO接枝量的增多,H-ESO-HEC-Na高分子表面活性剂的起泡和稳泡能力逐渐增强;通过对H-ESO-HEC-Na水溶液/庚烷的界面张力进行测试,发现不同条件制备得到的H-ESO-HEC-Na水溶液/庚烷的最低界面张力值接近,为9.8 m N/m左右。