醇添加对钴基催化剂费托合成反应的影响

在固定床微反应器上利用全产物在线分析方法, 研究了钴基催化剂上伯醇C_nH_2n+1OH (n=2, 3, 5, 6)在惰性气氛(Ar)和氢气气氛下的反应行为以及添加C_nH_2n+1OH对费托(FT)合成反应的影响, 并结合原位漫反射傅里叶变换红外光谱(DRIFTS)表征. 结果表明: 碳数为n的醇在Ar 气氛和H₂气氛下反应主要有脱羰和脱水两条反应路径, 分别生成碳数为n-1的烃和相同碳数的烃. 低碳数醇(乙醇和正丙醇)的添加对费托合成产物分布无明显影响; 而较高碳数的醇(正戊醇, 正己醇)的加入使碳数为n-1以上烃的选择性显著增加, 这是由于C_nH_2n+1OH加入后生成的碳数为n-1和n的中间体可进一步发生链引发反应, 生成更多的长链烃.     

激光溅射-分子束法研究镁、铝离子与乙腈分子的气相化学反应

利用激光溅射-分子束技术研究了Mg+、 Al+与乙腈分子的气相团簇反应.根据反射式飞行时间质谱检测的结果发现, Mg+、 Al+与乙腈分子反应形成不同尺寸的团簇离子产物,其中Al+与(CHCN)n的结合数n=1～10,而Mg+与(CHCN)n的结合数n=1～5. Al+(CHCN)n、 Mg+(CHCN)n团簇离子产物的强度分布都存在明显的强度间隙现象. Al+与(CHCN)n进行缔合时,出现了两个强度间隙;而Mg+与(CHCN)n进行缔合时,则只存在一个强度间隙. Al+的第一强度间隙在n=4～5,第二强度间隙在n=6～7;而Mg+的强度间隙在n=2～3.     

甲基丙烯酸三丁基锡酯与甲基丙烯酸甲酯共聚物的

研究了不同投料比的甲基丙烯酸三丁基锡酯(TBTMA)与甲基丙烯酸甲酯(MMA)共聚物的合成和分级方法,测定了各级分的分子量和对应的特性粘数,订定了Mark-Houwink方程式的K、α值.当n(TBTMA)∶n(MMA)=1∶1时,K=0.225,α=0.46,d=2.32.当n(TBTMA)∶n(MMA)=1∶2时,K=1.69×10-4,α=1.18,d=1.23.     

元素周期表各周期元素数的推算

用数学公式、算式表示周期表的一些特性的先例不少,特别是对于元素周期表中各周期所含的元素数以及与其对应的能级组的关系式更是不乏其例。如郎格茂根据椭性气体元素的原子序数2、10、18、36、54、86,用其相邻的两惰性气体的原子序数之差的求法、涅克拉索夫用通式[2n+3+(-1)~n]~2的计算、柯列奇考夫斯基提出的奇数周期元素数为0.5(n+1)~2、偶数周期元素数为0.5(n+2)~2的计算,都只给出对应于第n周期的元素数,而不能同时给出第n周期能级组的亚层情况,所以也就不能按能级组揭示划分周期的本质。     

何谓Y-芳香性

一谈到芳香性自然会联想到环状共轭体系。诸如苯、轮烯(中性分子或离子)及其同系物。由于它们具有特定的封闭层电子结构,π(p)电子沿环式周边离域而赋予体系一定的稳定化作用,一般说其周边的π(p)电子数符合Huckel(4n 2)规则。此外,分子轨道通过空间相互作用也可以使π(p)电子离域,从而产生一定的稳定化作用。由此又引伸出了同芳香性(homoaromaticity)与双环芳香性(bicycloaromaticity)。前者的π电子数符合Huckel(4n     

金属醋酸盐催化合成聚丁二酸乙二醇酯预聚体和碳酸二甲酯

研究了醋酸盐催化碳酸乙烯酯（EC）和丁二酸二甲酯（DS）同时合成聚丁二酸乙二醇酯 (PES) 预聚体和碳酸二甲酯(DMC)的耦合反应新工艺。 采用气相色谱-质谱联用定性分析馏分组成;红外光谱、核磁共振表征了预聚物的结构;采用乌式粘度计测试了预聚物的特性粘数;气相色谱定量测定馏分碳酸二甲酯的收率以考察耦合反应的进度。 以对该反应催化效果最佳的无水醋酸锂为催化剂考察了物料配比、反应温度、反应时间、催化剂用量对耦合反应的影响,结果表明,最佳的工艺条件为：反应温度195～200 ℃,n(EC)∶n(DS)=2∶1,n(cat)∶n(EC+DS)=0.02∶1,反应时间为2 h,耦合反应所得的DMC收率为48.0%,聚丁二酸乙二醇酯预聚物的特性粘数为0.3787。     

FeCl_3/磷酸三丁酯催化四氯化碳与氯乙烯的调聚反应:结构与活性

以四氯化碳与氯乙烯的调聚反应为目标反应,研究了Fe Cl3/磷酸三丁酯(TBP)配合物在反应体系中的结构,并关联了其结构与催化活性.采用摩尔电导、红外光谱和紫外吸收光谱对配合物的结构进行表征,结果表明Fe Cl3/TBP配合物在四氯化碳溶剂中为加合物Fe Cl3(TBP)n(n=1,2和3),配位数n由TBP与Fe Cl3的化学计量数决定.通过表观动力学实验研究了该配合物的催化反应活性,实验结果表明反应表观速率常数(kobs)随着TBP与Fe Cl3的摩尔比(r)的增大而增大,反应引发期(t0)随着r的增大而减小.假定反应遵循链式氧化还原机理,推导了kobs和t0的表达式,表达式和实验结果一致,均表明kobs只与配合物Fe Cl3(TBP)n的配位数和浓度有关.     

链式多Li掺杂分子H(HC==N-Li)nH(n=1~6)的NLO性质及链长依赖性

对链式多Li掺杂体系H(HCN-Li)_nH(n=1~6)的结构与性质进行了研究. 发现随着链长n的增大, 体系中有两类分子出现. 当n=1, 2时, 由于额外电子轨道是空的, 从而形成了Li 盐分子; 而当n=3~6时, 额外电子轨道是占据的, 从而形成了具有大范围额外电子云的多Li电子化物分子. 对于系列体系H(HCN-Li)_nH(n=1~6), 其非线性光学(NLO)性质的依赖性呈现阶梯式增长的规律, 即静态第一超极化率β₀的次序为2179, 2776(n=1, 2)< 5492, 5487(n=3, 4)< 15235, 15377(n=5, 6), 表明增加Li原子掺杂数是提高NLO响应的新途径.     

丙烯酸十八酯共聚物的结晶和熔融行为研究

合成了丙烯酸酯(AAn,n为侧链碳原子数)均聚物(PAAn)以及AA18与其同系物的无规共聚物((P(AA18-co-AAn)),并研究了P(AA18-co-AAn)的结晶和熔融行为.结果表明,在AA18与结晶同系物AAn(n=10,12,14,16)的共聚物中,结晶度(Xc)随AA18含量的增加而增大,相应的熔程先增加后下降,存在一个最大值;P(AA18-co-AA14)和P(AA18-co-AA16)的相对结晶度(Xc/Xcmax)受AA18含量影响不大,而P(AA18-co-AA10)和P(AA18-co-AA12)的Xc/Xcmax随AA18含量增加先下降后上升;随着AA18与共聚组份侧链碳原子数差别的增大,熔程的最大值明显增加.在AA18与非结晶同系物AAn(n=4,6,8)的共聚物中,Xc和Xc/Xcmax值随AA18含量的增加而增大,而Xc/Xcmax值随AAn侧链碳原子数的增加而减少,共聚物熔程的最大值差别不大.     

吸光光度多组分同时测定方法研究——MR和PLS法测定钴、镍、铜三组分混合体系

用偏最小二乘法(PLS)和多元线性回归法(MR)分别对钴、镍、铜三组分混合体系进行同时测定,证明PLS法对光谱重叠严重的体系较MR法有更好的预报准确性.着重讨论了校正集样品数n、波长数,和特征变量数d等测定参数对预报结果的影响.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.