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以甲基丙烯酸(MA)和十二醇(LA)为原料,对甲苯磺酸为催化剂,对苯二酚为阻聚剂,甲苯为带水剂,采用直接酯化法制备了甲基丙烯酸十二酯。通过研究原料的配比、催化剂用量、阻聚剂用量、带水剂用量等对酯化反应酯产率的影响,得到了制备甲基丙烯酸十二酯的最佳工艺配方。实验表明,在140℃下,当n(MA)∶n(LA)=2∶1,对甲苯磺酸质量分数为1.5%,对苯二酚质量分数为0.06%,甲苯质量分数为50%时,反应4h,酯化反应的酯产率达到98.02%。碱的强弱对酯收率影响不大。通过红外光谱分析,酯化反应产物为甲基丙烯酸十二酯。 相似文献
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以十六烷基三甲基氢氧化铵为催化剂和对苯二酚为阻聚剂,由甲基丙烯酸甲酯和乙二醇合成了甲基丙烯酸β-羟乙酯。通过正交实验获得了最佳反应条件:反应温度100℃~110℃,反应时间2.5h,酯醇摩尔比1∶1.5,催化剂用量为9.0ml。HEMA的产率为92.3%。 相似文献
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甲基丙烯酸β—羟乙酯的合成研究 总被引:1,自引:0,他引:1
以十六烷基三甲氢氧化铵为催化剂和苯二酚为阻聚剂,由甲基丙烯酸甲酯和乙二醇合成了甲基丙烯酸β-羟乙酯,通过正交试验获得了最佳反应条件,反应温度100℃~110℃,反应时间2.5h,酯醇摩尔比1:1.5,催化剂用量为9.0ml,HEMA的产率为92.3%。 相似文献
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聚乙二醇/聚己内酯三嵌段共聚物的合成与表征 总被引:3,自引:0,他引:3
以甲苯二异氰酸酯 (TDI)为偶联剂 ,合成了聚乙二醇 (PEG) /聚己内酯 (PCL)两亲性三嵌段共聚物 (PEG-b-PCL -b -PEG ,PECL) ,采用IR、1 H-NMR、DSC和WAXD分析和研究了PECL的结构与性能。实验结果表明 ,PECL的结构和组成与设计相一致 ,结晶度和熔点均低于均聚物 ,且随着PECL中PCL嵌段含量的增加 ,PCL嵌段熔点升高。透射电镜照片显示PECL纳米粒呈核 /壳结构的球形。 相似文献
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使用人工神经网络算法对枞酸乙二醇单酯与双酯合成反应正交试验数据进行辅助分析,探讨了反应温度、催化剂用量、反应物料比、反应时间对反应转化率及选择性的影响。结果表明:反应温度是关系酯化反应选择性的决定因素,反应物料配比是次要因素,投料比可以向目的物的构成比例方向优化,并可减少催化剂的用量。 相似文献
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精细有机化学品合成中醇的催化氧化新进展 总被引:1,自引:0,他引:1
综述了使用洁净氧化剂(氧气、过氧化氢),液相催化氧化有机醇的新进展。并对均相及多相催化剂体系中催化氧化有机醇在精细化学品合成中的应用进行了比较。 相似文献
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Partially (20–75%) acylated isopropylidene‐bis[1,4‐phenyleneoxy(2‐hydroxytrimethylene)] dimethacrylate (BisGMA) was prepared by a single step reaction of 2,2‐bis[4‐(2,3‐epoxypropoxy)phenyl]propane (DGEBA) with methacrylic acid (MAA), methacrylic anhydride (MAAn) and/or acetic anhydride catalyzed by 0.8 mol‐% N‐methylimidazole at 90–100°C. In any case, MAA was substituted by an equimolar quantity of the anhydride. The reaction kinetics of DGEBA with MAA and MAAn follows a first order law up to a conversion of epoxy groups corresponding to the initial molar ratio of MAAn. For different mole fractions xMAA, the reaction rate was found to be directly proportional to x0.5MAA. The viscosity of BisGMA decreased with an increase in the acylation degree. Acylated BisGMA was copolymerized with triethylene glycol dimethacrylate (TEGMA) by use of a redox initiator system at room temperature and with vinyltoluene (VT) initiated by di‐tert‐butyl peroxide at 150–200°C, respectively, both in the presence of 70–76 wt.‐% of quartz filler. Different dependencies of the content of sol and the conversion of C=C double bonds were observed for thermally polymerized composites from VT with acetylated and methacrylated BisGMA, respectively. Methacrylated BisGMA yielded composites with reduced water uptake. The higher network density of the polymer matrix with methacrylated BisGMA resulted in a higher glass transition temperature Tg and a higher storage modulus of the composites. The initial temperature of weight loss of composites with VT was increased from 230°C for composites with BisGMA up to 258°C for composites with BisGMA methacrylated to a degree of 40%. 相似文献
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由简单的烷基胺与丙烯酸甲酯为原料,经Michael加成、Dieckmann环合、脱羧得到三种N-烷基-4-哌啶酮。这些N-烷基-4-哌啶酮分别与(R)-(-)-2-氨基-1-丁醇和多聚甲醛进行Mannich反应,再经黄鸣龙还原得到三种新的具有手性的双哌啶氨基醇衍生物。采用1H NMR、13C NMR、IR、MS对目标产物的结构进行了表征,并对其旋光度进行了测定。Mannich反应优化条件为:甲醇回流温度下反应,物料摩尔比为n(N-烷基-4-哌啶酮)∶n((R)-2-氨基-1-丁醇)∶n(多聚甲醛)=1∶1.2∶2.5。 相似文献
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Synthesis, characterization and properties of chitosan modified with poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers 总被引:1,自引:0,他引:1
Synthesis of poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers is discussed herein. Siloxane prepolymer was first prepared via acid-catalyzed ring-opening polymerization of octamethylcyclotetrasiloxane (D4) to form polydimethylsiloxane (PDMS) prepolymers. It was subsequently functionalized with hydroxy functional groups at both terminals. The hydroxy-terminated PDMS can readily react with acid-terminated poly(ethylene glycol) (PEG diacid) to give PEG-PDMS block copolymers without using any solvent. The PEG diacid was prepared from hydroxy-terminated PEG through the ring-opening reaction of succinic anhydride. Their chemical structures and molecular weights were characterized using 1H NMR, FTIR and GPC, and thermal properties were determined by DSC. The PEG-PDMS copolymer was incorporated into chitosan in order that PDMS provided surface modification and PEG provided good water swelling properties to chitosan. Critical surface energy and swelling behavior of the modified chitosan as a function of the copolymer compositions and contents were investigated. 相似文献
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聚乙二醇—环氧树脂多嵌段共聚体的合成与表征 总被引:2,自引:1,他引:1
以三乙基苄基氯化铵为催化剂 ,将聚乙二醇 10 0 0 0 (数均分子量 1 2 7× 10 4 )、邻苯二甲酸酐和环氧树脂E 4 4 (平均分子量 4 54 5)进行共缩聚 ,制得聚乙二醇 环氧树脂多嵌段共聚体 ,其数均分子量为 5 4 7× 10 4 ,共聚体的平均嵌段数目约为3- 4。这种共聚体具有水溶性。用滴体积法测定了该多嵌段共聚体水溶液的表面张力 ,结果表明 :2 5℃时 ,浓度范围为0 0 0 5~ 0 0 1g/mL的多嵌段共聚体水溶液的最低表面张力值约为 52mN/m ,其降低表面张力的能力仅略高于PEG10 0 0 0。 相似文献