马来酸酐改性蓖麻油制备交联型水性聚氨酯

以马来酸酐与蓖麻油制备含碳碳双键的三羧基蓖麻油(MACO)作为内交联剂,合成改性蓖麻油水性聚氨酯乳液(MACO-WPU)。采用FT-IR和XRD对改性聚氨酯的结构进行表征,证实MACO被成功引入到聚氨酯大分子链中且分子链呈现无序状态。通过对力学性能、吸水率、粒径、热重分析等研究了MACO用量对聚氨酯乳液及胶膜性能的影响,结果表明:当w(MACO)=3%时,乳液外观和稳定性好,平均粒径为48.45 nm; 胶膜的拉伸强度和断裂伸长率分别为13.15 MPa、195%;与未改性WPU相比热稳定性略有提高。     

微波下蒽与马来酸酐的Diels-Alder反应

微波加热在Diels-Alder反应中的应用结果显示其具有反应时间短和收率高的优点。产物经红外、核磁表征与结构吻合,该法影响收率的主要因素是微波功率和辐射时间。理想的合成条件为微波功率300 W,辐射时间为4 min,收率可达93.4%。     

马来酸酐改性邻甲酚醛环氧丙烯酸酯的动力学及应用

研究了马来酸酐改性邻甲酚醛环氧丙烯酸酯的动力学,并确定了动力学方程,分析了液态感光成像油墨在应用中出现低显和过显问题的原因,并提出了解决办法。研究结果表明,马来酸酐改性邻甲酚醛环氧丙烯酸酯遵循一级动力学模型,其反应的表观活化能Ea=23.74 kJ/mol,指前因子A=1.383 9×103m in-1,反应速率可以由dαdt=1.383 9×104e-823.314 7.40T(1-α)来定量描述;曝光强度、显影速度和喷淋压力是影响低显和过显问题的三个主要因素。     

马来酸酐改性蓖麻油制备耐光性聚氨酯复鞣剂——乳液性能研究

用马来酸酐改性蓖麻油(MCO)合成了一系列不同组成的耐光性聚氨酯复鞣剂水乳液(MC-PUR),研究了复鞣剂中—COOH质量分数、n(NCO)/n(OH)、m(MCO)/m(PEG1000)对乳液电导率、黏度、临界聚沉值(CC.C)、耐酸稳定性的影响。结果表明,随—COOH质量分数从3%增大到7%,电导率从1 556μs/cm增大到3 435μs/cm,黏度先从168 mPa.s增大到224 mPa.s,后又降低到85 mPa.s,当w(—COOH)=5%时,黏度达到最大值;随n(NCO)/n(OH)从0.5增大到0.9,电导率从2 943μs/cm降到2 464μs/cm,黏度从428 m Pa.s降到224 mPa.s;随m(MCO)∶m(PEG1000)从1∶1增大到3∶0,黏度从224 mPa.s降到67 mPa.s;CC.C随—COOH质量分数增加和m(MCO)/m(PEG1000)增大而降低;耐酸稳定性结果证明,当w(—COOH)=3%~5%,m(MCO)∶m(PEG1000)=1∶1,n(NCO)/n(OH)=0.5~0.9时,MC-PUR适用于皮革复鞣工序。     

Reaction Kinetics of Soybean Oil Transesterification Using Heterogeneous Metal Oxide Catalysts

Homogeneous acid or base catalysts dissolve fully in the glycerol layer and partially in the fatty acid methyl ester (biodiesel) layer in the triglyceride transesterification process. Heterogeneous (solid) catalysts, on the other hand, can prevent catalyst contamination making product separation much simpler. In the present work, the transesterification kinetics of five different solid catalysts with soybean oil is presented. It is found that heterogeneous catalysts require much higher temperatures and pressures to achieve acceptable conversion levels compared to homogeneous catalysts. Subsequent to preliminary investigations, transesterifications were conducted for selected high performance solid catalysts, i.e., MgO, CaO, BaO, PbO, and MnO₂ in a high pressure reactor up to a temperature of 215 °C. The yield of the fatty acid methyl esters and the kinetics (rate constant and order) of the reaction are estimated and are compared for each catalyst.     

Kinetics and Mechanism in the Liquid-Phase Hydrogenation of Maleic Anhydride and Intermediates

The influence of zinc oxide on the kinetics and mechanism of the liquid-phase hydrogenation of maleic anhydride (MA) and intermediates was investigated on copper-based catalysts. No influence of zinc oxide on the hydrogenation of maleic anhydride was observed in previous experiments. The discontinuous hydrogenation of succinic anhydride (SA) resulted in the formation of γ-butyrolactone (γ-BL) and 1,4-butanediol (1,4-BD) on a copper/zinc catalyst. On a zinc-free copper catalyst only γ-butyrolactone was formed while the hydrogenation of γ-butyrolactone to 1,4-butanediol was inhibited. It was observed that succinic anhydride which is adsorbed on the copper surface of the catalyst prevents the adsorption of γ-butyrolactone. On copper/zinc catalysts the reversible adsorption of succinic anhydride on the inactive zinc oxide crystallites, which led to a reversible decrease of the carbon balance, is responsible for a decrease of the succinic anhydride coverage of the copper sites. It appears that the decrease of the succinic anhydride coverage of the copper surface is proceeding by surface diffusion of succinic anhydride to the adjacent zinc oxide crystallites. On this basis two different reaction pathways via succinic anhydride adsorbed on the copper surface and via succinic anhydride adsorbed on the zinc oxide crystallites were proposed for the hydrogenation of maleic anhydride and intermediates. Kinetic modeling of the reaction pathway taking into account both reaction pathways led to good agreement of calculated and experimental results.     

马来酸酐与三羟甲基丙烷酯化反应

用马来酸酐(MA)与三羟甲基丙烷(TMP)经酯化反应制备系列三羟甲基丙烷马来酸单酯(TMPMs)。重点考察投料比、反应温度、时间、催化剂等对酯化反应的影响。结果表明,90℃下,n(MA)∶n(TMP)低于2.5∶1时,在240 min内MA单酯化率可达99%以上;n(MA)∶n(TMP)=3∶1时,需添加占单体总质量0.2%的对甲苯磺酸催化剂,MA酯化率方可达99%以上。采用NMR对产物的结构和组成进行表征和分析,通过酯化率计算其平均双键官能度。     

Kinetics of Isothermal Ethanol Adsorption onto a Carbon Molecular Sieve under Conventional and Microwave Heating

The isothermal kinetics of ethanol adsorption from aqueous solution onto a zeolite type carbon molecular sieve (CMS‐3A) under conventional heating (CH) and microwave heating (MWH) was investigated. The adsorption kinetics is described by the model of a phase‐boundary controlled reaction for both heating modes. The activation energy (E_a) for the adsorption process under MWH is lower than under CH while the preexponential factor (lnA) is higher. Ethanol adsorption is a kinetically complex process whose complexity changes with the mode of heating. The established decrease in E_a and increase in lnA under MWH compared to CH is explained with the increase in the ground vibrational level of the – OH twisting vibrations in the ethanol molecule and with the decrease in its anharmonicity factor which is caused by the selective resonant transfer of energy from CMS‐3A to the OH oscillators.     

Millistructured Reactor as Tool for Investigating the Kinetics of Maleic Anhydride Synthesis

A nearly isothermal millistructured fixed-bed reactor was used to investigate the kinetics of the selective oxidation of n-butane to maleic anhydride. In addition to the investigation of a broad range of industrially relevant conditions, the focus was on the influence of the reaction products on the kinetics. For this purpose, a saturator for the accurate dosing of the target product MA was developed. The experimental data were used to derive a reaction network comprising the by-products acetic and acrylic acid. Additionally, the inhibition of the associated reactions by reactants and products was investigated.     

Linkage Configurations at the Cyclic Maleic Anhydride Units and Sequence Distribution in Copolymers of p-Chlorostyrene with Maleic Anhydride

Semi-alternating copolymers were formed in the radical copolymerization of p-chlorostyrene (p-ClSt) with maleic anhydride (Man) in CCl₄ solutions at 50°C. The triad distributions in the copolymers and the ratio of the amounts of entgegen (E) and zusammen (Z) linkage configurations at the cyclic Man units in the copolymers were determined by using ¹³C nuclear magnetic resonance spectroscopy. The equilibrium constant of the electron donor–acceptor complexation of p-ClSt and Man in CCl₄ solution was determined to be 0·32±0·03M ^-1 at 23°C. A non-linear least-square regression of the triad distribution data showed that the copolymerization models which involved complex participation were preferable, although not conclusively, to the penultimate unit model. As much as 40% of the linkages at the Man units in the semi-alternating copolymers were found to be in the Z configuration, strongly indicating a participation of the donor–acceptor complex formed between p-ClSt and Man. © of SCI.     

顺酐化豆油改性不饱和聚酯树脂腻子的制备

以顺酐化豆油及油酸封端对腻子专用UPR进行改性,采用三步加料逐步升温催化熔聚法,研究了从多元醇、酸体系及其醇过量、顺酐化豆油的用量、油酸封端比例对UPR性能的影响。试验发现利用顺酐化豆油的用量为11.53%,采用5%的油酸进行封端时,醇过量为12.24%~15.15%,合成的UPR性能较好,其中14.94%为最佳的醇过量值,得到的新型金属腻子专用树脂性能优良。并探索调整一套适用于新型腻子树脂的填料体系,制得一种环保型的金属腻子。     

混合溶剂法回收顺酐

研究了有机溶剂回收顺酐的行为和性质,筛选了物理性能好,饱和溶解度大,吸收性能好的混合溶剂为吸收剂,进行了模拟工业连续吸收试验,确定了吸收和解吸的操作条件。顺酐的吸收率达99.7％以上,产品符合国家一级品标准。     

A New Reactor for Combined Conventional and Microwave Heating

A reactor system was developed to investigate the influence of microwaves on adsorption and desorption processes during heterogeneously catalyzed reactions. The reactor is free of temperature gradients and allows combined conventional and microwave heating. The hydroxylation of benzene with N₂O as an oxidant was used to test the reactor.     

棉籽油间歇式酯交换反应动力学的研究

生物柴油(棉籽油甲酯)可以由棉籽油与甲醇在催化剂KOH存在下通过酯交换反应制得。故对棉籽油间歇式酯交换反应动力学进行了研究,并考察了反应温度和催化剂浓度对产物棉籽油甲酯浓度的影响。用液相色谱法分析棉籽油的组成;用气相色谱法分析产物中棉籽油甲酯的含量。由实验数据绘制的动力学曲线得到酯交换反应在开始阶段为准二级反应,以后紧接转为一级反应和零级反应,与文献报导的棕榈油酯交换反应动力学结果一致。由实验数据求出酯交换反应在开始阶段的动力学参数,35℃、45℃时的反应速率常数分别为0.9179Lmol-1min-1和1.049Lmol-1min-1,酯交换反应的活化能为10.88kJmol-1。根据实验结果得到棉籽油酯交换反应的最佳反应温度为45℃,最佳催化剂为1.1%KOH。     

聚乙烯熔融法接枝马来酸酐的制备及表征

研究了加工工艺及环氧树脂的加入对聚乙烯接枝马来酸酐(PE-g-MAH)接枝反应的影响。结果表明:当引发剂浓度较低时,随着温度的提高,PE-g-MAH的接枝率增大,但其熔体流动速率降低;引发剂用量超过0.5 phr后,随着温度的提高,PE-g-MAH的接枝率及熔体流动速率基本保持不变。随着环氧树脂用量的增加,PE-gMAH的接枝率增大,当环氧树脂用量为1.2 phr时,接枝率达到最大,熔体流动速率降至最低。环氧树脂的加入促进了马来酸酐的接枝,在PE大分子链上引入了新的极性基团。与PE相比,PE-g-MAH的结晶峰温提高,结晶度降低。     

微波辐射合成多功能腐植酸-马来酸酐共聚物陶瓷添加剂

采用微波辐射技术,以天然有机质钠盐腐植酸钠(NaHA)为原料,以马来酸酐(MA)为改性单体,通过自由基共聚合制备了新型腐植酸钠-马来酸酐共聚物(NaHA-co-MA)陶瓷添加剂。探讨了引发剂种类对陶瓷泥浆流动性的影响,确定硝酸铈铵为最有效引发剂。通过正交试验得到最佳合成条件为引发剂用量0.04%(质量分数)、NaHA与MA质量比1.2∶1.0、微波功率320W、间歇辐射时间15min、聚合后中和程度pH为7.5,此时陶瓷泥浆的相对黏度为1.34,流动性最好。采用红外光谱分析及坯体强度、可塑性测试等手段对NaHA-co-MA结构和性能进行分析:红外光谱显示NaHA结构中的-OH为与MA接枝共聚的活性点;坯体强度和可塑性试验表明,当NaHA-co-MA添加量为基体的0.08%(质量分数)时,坯体的干燥强度达4.16mPa,可塑性指标为5.49kg.cm,经与NaHA比较,综合性能有较大提高。     

水洗法脱除马来酸酐接枝副产物聚马来酸酐的研究

用马来酸酐(MAH)对氯化聚丙烯(CPP)进行了接枝,以水洗法代替丙酮萃取法脱除接枝物(CPP-g-MAH)中的副产物聚马来酸酐.对水洗接枝物进行红外光谱表征和附着力、溶解度参数的测定,考察了温度、时间、加水量对水洗率的影响.结果表明:当温度90℃、时间2 h、加水量325 mL时水洗率最大;采用水洗法不影响接枝物在聚丙烯板上的附着力.     

顺丁烯二酸酐的IR定量分析

用红外光谱定量测定顺丁烯二酸酐的含量,选择了无干扰的729～675cm~(-1)峰为基准。该法定量测定顺丁烯二酸酐准确、快速。     

The Effect of Water on the Transesterification Kinetics of Cotton Seed Oil with Ethanol

A kinetic model for the transesterification of a cotton seed oil with ethanol in the presence of water is proposed. The effect of water content in the reacting mixture on the transesterification reaction is studied. The dependence of the equilibrium constants and reaction rate constants on the water content is presented. Equilibrium was reached within less than 30 min reaction time in all cases. The increase of the water content results in decrease of the conversion level of the oil. By increasing the ethanol/oil ratio the conversion of triglyceride increases and the concentration of mono- and diglyceride in the product mixtures are reduced.     

Using Microwave Heating and Microscopy to Estimate Optimal Corn Germ Oil Yield with a Bench-Scale Press

The increase in ethanol production from corn has prompted development of processes to separate corn germ. The corn germ co-product would be a source of corn oil if a practical oil separation process were also developed. We carried out bench-scale corn-germ-pressing experiments to determine the maximum potential oil recovery which were then used to estimate commercial germ crushing costs. Corn germ was preheated in a microwave oven and oil was then extracted with a bench-scale press. Preheating the germ was necessary to obtain good oil yields. The uniform heating of the microwave oven more closely resembles compressive heating of commercial scale presses than does oven heating. Three different microscopic techniques were used to examine the effects of microwave and conventional-oven heating on corn germ. Microscopy revealed that microwave heating heated oil in the germ more quickly than the other components of the germ. Heating by both methods destroyed lipid body membranes and oil coalesced and pooled. Less oil could be pressed from germ initially containing 3–6% moisture than germ containing 15–20% moisture. Maximum oil recovery of about 65% was obtained for all germs tested when the optimum press temperature and germ feed moisture were used. Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture.