具Ⅱ型Hlling功能性反应捕食系统解的性质

研究一个齐次Neumann边界条件弱耦合的反应扩散系统.利用Lyapunov函数及局部稳定性给出了正常数解全局渐近稳定的充分条件,并由此说明,只要食饵的出生率足够大、或者捕食者的捕获率足够小、或者捕食者的内部竞争充分强,正常数解就是全局渐近稳定的.另外,还证明了只要一个物种的扩散率足够大,则稳态系统不存在非常数解.     

生质柴油碱性均匀相触媒制程研究

生质柴油为重要之可再生能源。本文研究改善液相触媒制程,以降低甲醇与三酸甘油酯间界面阻力,以提生反应速率。实验结果发现,在批式制程中,提高搅拌速率可提升反应速率,然因工厂实际操作恐有困难。以相转移触媒可达增加反应速率与产率效果,但需注意选用之相转移触媒不可在强碱下被破坏。使用共溶剂THF可促进反应速率与产率,为一可行的选择。而连续制程较批式制程有较好的效率。     

直接缩聚法合成淀粉接枝可降解聚酯和聚酯酰胺及其表征

以可溶性淀粉、乳酸、乙醇酸和己内酰胺为原料在氯化亚锡催化下直接缩聚制备得到了淀粉接枝乳酸-乙醇酸共聚物及淀粉接枝乳酸-乙醇酸-己内酰胺共聚物。用核磁共振(NMR)、差热(DSC)及热重(TG)分析分别对产物的结构和热性能进行了表征。     

光接枝聚合制备双极膜的影响因素研究

以丙烯酸(AA)为接枝单体,二苯甲酮(BP)为主引发剂,二乙烯基苯(DVB)、新戊二醇二丙烯酸酯(NPGDA)为交联剂,在均相阴离子交换膜表面,通过光接枝聚合得到聚丙烯酸型阳离子交换层,形成单片型双极膜结构.考察了光照时间、交联剂用量、引发剂浓度等对光接枝聚合反应的影响.不加交联剂时,单纯以BP为引发剂,接枝程度随反应时间延长而增加,但接枝程度低;交联剂的加入可明显的提高接枝程度,在反应时间为60s左右,接枝程度最大;NPGDA做交联剂时,接枝程度高于二乙烯基苯;以2,4,6-三甲苯甲酰基-二苯基氧化膦(TPO)为共引发剂,NPGDA用量为单体量的2.5%时,接枝程度最高,为30.1%.采用均聚型引发剂与接枝型引发剂(BP)复配,可提高接枝程度,但在浓度相同时接枝程度最低.     

一类带有局部化源的反应扩散方程组解的整体存在性及爆破

考虑一类带有局部化源项的反应扩散方程组.在适当的假设下,用上、下解法得到了该问题的解在有限时刻爆破及整体存在的充分条件.     

Bis-Wittig反应法合成不对称二烯腊肪酸酯

双季鏻盐1与n-BuLi反应生成膦双叶德2,接着与两种不同的醛发生bis-Wittig反应成功地合成了天然产物二烯脂肪酸甲酯7a及两个新的类似物7b和7c,产率为24%～30%.该法具有原料易得,路线短等特点.产物的结构用IR、1HNMR、和Ms等进行了表征.图3,参16.     

标准态下碳酸二甲酯合成体系热力学分析

 用Benson基团贡献法计算了碳酸二甲酯(DMC)的热力学数据标准摩尔生成焓Δ_fH_m^θ、标准摩尔生成吉布斯自由能Δ_fH_m^θ和等压摩尔热容C_p,m;在标准态下,300~1 000 K温度范围内对比了甲醇或二甲醚(DME)氧化羰化合成DMC,甲醇或DME与CO₂直接合成DMC,由合成气合成DMC,DME,甲醛或甲醇这些反应的焓变Δ_fH_m^θ、吉布斯自由能变Δ_fH_m^θ和平衡常数lnK^θ.计算结果表明:在讨论的条件范围内,由DME氧化羰化合成DMC是热力学上可自发进行的反应,但DME和CO₂反应合成DMC与甲醇和CO₂反应合成DMC,均不能自发进行(需要通过耦合等方式来改变反应途径或重构反应体系,该反应才有可能进行).此计算将为合成DMC的反应路线设计以及新催化剂体系的探索提供热力学依据.     

SIS/甲基丙烯酸酯接枝改性胶粘剂的研制

以甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(BMA)为单体,或以其混合物为接枝单体,对聚苯乙烯-聚异戊二烯-聚苯乙烯(SIS)进行接枝共聚制备溶剂型胶粘剂.研究了引发剂用量、单体配比、反应温度及反应时间对胶粘剂性能的影响.结果表明:单体MMA的适宜用量为SIS总质量的15%左右,BMA的用量为SIS质量的20%,MMA与BMA适宜配比为2∶1,引发剂用量为SIS总质量的1.0%,反应温度为85℃,反应时间为4 h左右.     

Preparation of polypropylene/montmorillonite nanocomposites by intercalative polymerization： Effect of in situ polymer matrix functionalization on the stability of the nanocomposite structure

The copolymerization of propylene and 5-hexenyl-9-borabicyclo[3.3.1]nonane (5-hexenyl-9-BBN) has been conducted with an MgCl2/TiCl4 catalyst intercalated in an organically modified montmorillonite (OMMT) with triethylaluminum (AlEt3) cocatalyst and diphenyldimethoxysilane (DDS) external donor. This polymerization process simultaneously results in both the exfoliation of MMT layers to realize the preparation of polypropylene (PP)/MMT nanocomposites and the implantation of reactive borane groups in the formed PP matrix. The polymer-borne borane groups have been able to undergo an effi-cient hydrolysis process under very mild reaction conditions (40℃, 3 h, in THF), introducing hydroxy groups into PP without sacrificing the polymerization-formed nanocomposite structure (the exfoliation of MMT). The resultant hydroxyl-functionalized PP/MMT nanocomposites exhibit enhanced structural stability against processing compared with those based on unfunctionalized PP matrix.     

Experimental investigation of incremental reactivity of di-tert-butyl peroxide

Large quantities of di-tert-butyl peroxide (DTBP) have been emitted into the troposphere due to human activities. Its role in the atmospheric photochemical reaction has not been understood. This study presents the results of the photochemical reactions of DTBP and NOx, which have been simulated in a self-made smog chamber under the temperature of (29±1)℃. Both the wall decays of ozone and NO2 could be neglected, compared to the results in simulative experiments. The effective intensity of UV light used in the experiments was 1.28×10-3 s-1, which was expressed by the rate constant of NO2 photolysis in purified air. The reaction mechanism was proposed according to our results and reports of other researchers. The maximum values of incremental reactivity (IR) in the three simulative ex- periments were 9.53×10-2, 5.23×10-2 and 3.78×10-2, respectively. The incremental reactivity decreased with the increase of initial concentrations of DTBP. The IR value of DTBP obtained in this study was comparable to that of acetylene reported in our previous research.