炔基聚硅烷的合成研究

甲基苯基二氯硅烷以Wurtz反应合成聚甲基苯基硅烷,然后与乙酰氯在三氯化铝存在下发生氯交换反应得到含氯聚硅烷,含氯聚硅烷与对三甲基硅乙炔苯基锂反应即可得到侧链含有三甲基硅乙炔基的聚硅烷。经核磁共振氢谱和红外光谱分析,证实产物为侧链含有三甲基硅乙炔基的聚硅烷。     

β-氰乙基聚硅烷的合成与性质研究

以甲基二氯硅烷、丙烯腈为原料，通过硅氢加成反应合成了β-氰乙基甲基二氯硅烷；然后采用钠缩合法将其分别与甲基苯基二氯硅烷和二苯基二氯硅烷共聚，制得了两种二元共聚硅烷——聚（β-氰乙基甲基-甲基苯基）硅烷[P1]、聚（β-氰乙基甲基-二苯基）硅烷[P2]。并用IR、UV、^1HNMR、GPC和荧光光谱进行了表征。结果表明，β-氰乙基甲基二氯硅烷的反应活性与甲基苯基二氯硅烷相仿，低于二苯基二氯硅烷；此外，P2具有部分枝状聚硅烷的性质，Stoks位移达到80nm，荧光发射峰位于412nm，可能是少量枝化点的引入造成P2具有部分枝状聚硅烷的特征。     

聚甲基(对甲苯基)硅烷的合成与荧光性质

采用钠缩合法，将甲基(对甲苯基)二氟硅烷进行均聚，或分别与二甲基二氟硅烷、甲基苯基二氯硅烷、二苯基二氯硅烷进行共聚，合成了4种聚硅烷。用^1HNMR、IR、GPC进行了结构表征，并研究了聚硅烷固体和溶液的荧光性质。结果表明，聚硅烷的聚集态和构象对其荧光性质有较显著的影响。苯基对位甲基的给电子效应使最大荧光发射波长(λmax)略有红移；侧基的共轭作用和分子对称性可能也对其固体和溶液的λmax有较大影响；链长较长的聚硅烷荧光强度较大。     

聚甲基四苯基苯硅烷的合成及非线性光学性质的研究

在甲苯中，将甲基四苯基苯二氯硅烷与金属钾反应，或甲基四苯基苯二氯硅烷分别与甲基乙烯基二氯硅烷、甲基苯基二氯硅烷、二甲基二氯硅烷和二苯基二氯硅烷按摩尔比１∶１混合，再与金属钾反应，合成了聚硅烷１、２、３、４和５，分别用元素分析、ＩＲ、ＵＶ、１ＨＮＭＲ和ＧＰＣ作了表征，并测得它们的非线性谐波极化率Ｘ（３）的值分别为８．６×１０－１２、７．９×１０－１２、９．１×１０－１２、６．５×１０－１２和９．３×１０－１２ｅｓｕ。     

聚甲基环戊二烯基硅烷及其共聚物的合成与表征

用钠试剂法合成了甲基环戊二烯基二氯硅烷,采用钠缩合法将其均聚,并分别与二甲基二氯硅烷、二苯基二氯硅烷、甲基苯基二氯硅烷及甲基正丁基二氯硅烷进行共聚反应,合成了5种聚硅烷。并用IR、UV、^1H NMR、GPC和荧光光谱对它们进行了表征。     

聚甲基苯基硅烷及其共聚物的合成与表征

用格氏法合成了甲基苯基二氯硅烷,并用钠缩合法将它均聚或分别与二甲基二氯硅烷、二苯基二氯硅烷、甲基乙烯基二氯硅烷等共聚,合成了４种聚硅烷。用ＩＲ、ＵＶ、＾１Ｈ－ＮＭＲ和ＧＰＣ对它们进行了表征。     

以二硅烷馏分为原料合成硅取代聚硅烷的研究

以二硅烷馏分为原料，加入格氏试剂，通过Si-C1键的重排反应，获得1，1-二氯一1，2，2，2一四甲基二硅烷；再进一步进行钠缩合反应，获得了硅取代聚硅烷(SPS)。用FT-IR、UV、^(29)Si NMR、TG等研究了该聚合物的分子组成、基本结构及其热稳定性。结果发现，格氏试剂的加入量决定了1，1-二氯一1，2，2，2-四甲基二硅烷的产率；反应时间对SPS的产率有较大影响，一般以4～5h为宜。     

甲基二氯硅烷的化学反应及其综合利用

简述了甲基二氯硅烷的硅氢化反应、热缩合反应、水解反应和醇解反应，及其重要反应产物甲基氯丙基二氯硅烷、甲基乙烯基二氯硅烷、甲基三氟丙基二氯硅烷、甲基苯基二氯硅烷、甲基含氢环体和含氢硅油的制备和应用。     

双（N,N-二乙基）氨基甲基苯基硅烷的合成研究

以甲基苯基二氯硅烷和二乙胺为原料,低温下反应,合成了双(N,N-二乙基)氨基甲基苯基硅烷.通过正交试验方法考察了反应温度、反应介质、原料量之比以及反应时间等因素对目标产物产率的影响,利用红外光谱、核磁共振等手段对产物结构进行了表征和确认.利用方差分析确定的最佳反应条件为反应温度-15 ℃、溶剂为乙醚,二乙胺与甲基苯基二氯硅烷的量之比为5:1、反应时间为6 h.反应体系中加入三乙胺作为酸吸收剂、且用量为甲基苯基二氯硅烷的2倍时也可提高目标产物的产率;加入三乙胺后还可使铵盐副产物的后处理更易进行.     

依靠科技进步促进节能减排低价钛试剂促进的硅硅键的构造反应:官能化聚硅烷的合成

利用低价钛试剂是一个良好还原试剂的特性,在温和的条件下促进氯硅烷的还原偶联反应.在TiCl4/Zn还原体系作用下,R3SiCl进行二聚反应,生成相应的二硅烷,二氯硅烷进行缩聚反应,以良好的产率得到聚硅烷.在该反应条件下,底物中的官能团(如Si-H 键、乙烯基等)不受影响.所得到的聚硅烷有着较高的平均相对分子质量和较窄的相对分子质量分布.     

Polymeric Routes to Silicon Carbide

Several classes of organosilicon polymers are effective precursors for silicon carbide ceramic compositions. These include polydimethylsilane (via a two-step process), ‘polysilastyrene’, polycarbosilazanes or polysilazanes, and certain siloxanes, plus the branched polycarbosilanes, branched polysilahydrocarbons, and vinylic polysilanes developed at Union Carbide. The latter three classes are prepared by active metal dechlorinations of appropriate chlorosilane blends, leading to recognition of branching at backbone silicon atoms (either as prepared or during processing) as a prerequisite for obtaining useful ceramic yields. Fundamental reactivity differences between the active metals (potassium and sodium) allow the preparation of sodium-derived vinylic polysilanes. The latter offer certain economic and performance advantages as ceramic precursors.     

Branched polysilanes from tetrafunctional monomers

Tetrafunctional silicon monomers have been incorporated into soluble branched polysilanes. Tetrakis(chlorodimethylsilyl)silane has been homopolymerized to form an irregular branched polymer which may contain some spiro and some bicyclic units. This polymer shows weak absorption at 300 nm, the region of the linear polysilane chains. It emits broadly in the region from 400 to 500 nm. The copolymers of tetrakis(chlorodimethylsilyl)silane with dichlorodimethylsilane are also soluble and in the presence of l ge amount of the tetrakis monomer emit in the region from 400 to 500 nm. By contrast, copolymers with phenyltrichlorosilane emit strongly at 450 to 650 nm, due to the phenylsilane hyperbranched structure. Small amounts of tetrachlorosilane can be incorporated into soluble polysilanes. Incorporation of =Si=units into polymers withn-hexyl substituents is very inefficient but leads to minor changes in emission spectra. Incorporation into polymers with phenyl substituents affects luminescence and increases molecular weights and broadens polydispersities. Reaction with dimethyldichlorosilane provides soluble low molecular weight oligomers and polymers. Polymers prepared with a small proportion of tetrachlorosilane show absorption and emission typical for linear polymers. Polymers synthesized with higher proportion of tetrachlorosilanes emit broadly at 400 to 500 nm, indicating the presence of Si clusters. The silicon clusters entrapped into soluble polymers are very easily oxidized as seen by the siloxane peaks in²⁹Si NMR spectra and they should be treated under complete exclusion of oxygen.     

New ways to polysilanes

New cyclosilanes with substituents, which are functional groups, open the possibility of forming new polycyclic silanes in an aimed synthesis. This is possible on five- and six-membered rings. Also, mixed systems with different ring sizes were prepared. The UV spectra are discussed. An annelid dicycle Si₁₀Me₁₈ was also prepared. With this compound a radical anion can be formed. New aspects of the electrochemical synthesis of polysilanes are presented and a chlorine stable anode is proposed for the first time. The polymerization reaction of hydrogen-containing methyldisilanes is discussed. This reaction yields polysilanes with a general composition (SiMeH) _n and a ceramic yield over 88%. The reaction is very different from the known reaction of monosilanes. Disilanes react faster and to high polymers. Two reaction mechanisms seem to be working simultaneously, i.e., a mechanism as postulated in monosilanes and a disproportionation reaction. These mechanisms are discussed.     

Chemically Cross-linked Polysilanes as Stable Polymer Precursors for Conversion to Silicon Carbide

Cross-linked polysilanes were prepared by the co-polymerization of Me₂SiCl₂ or PhMeSiCl₂ with varying amounts of divinylbenzene (2–15% by weight) using molten sodium as the dehalogenating agent. All the cross-linked polysilanes were stable to air and could be processed thermally for conversion to silicon carbide. Polymers containing from 5–15% of the cross-linking agent underwent a uniform shrinkage during thermal treatment (1500 °C) to afford β-SiC in good yields. The ceramic was characterized by a variety of techniques including Raman and infrared spectroscopy, powder XRD, as well as Scanning Electron Microscopy (SEM). Dedicated to Prof. C. W. Allen in recognition of his outstanding contributions to inorganic polymers. Deceased in a tragic car accident in July 2004.     

New ways to polysilanes

New cyclosilanes with substituents, which are functional groups, open the possibility of forming new polycyclic silanes in an aimed synthesis. This is possible on five- and six-membered rings. Also, mixed systems with different ring sizes were prepared. The UV spectra are discussed. An annelid dicycle Si₁₀Me₁₈ was also prepared. With this compound a radical anion can be formed. New aspects of the electrochemical synthesis of polysilanes are presented and a chlorine stable anode is proposed for the first time. The polymerization reaction of hydrogen-containing methyldisilanes is discussed. This reaction yields polysilanes with a general composition (SiMeH) _n and a ceramic yield over 88%. The reaction is very different from the known reaction of monosilanes. Disilanes react faster and to high polymers. Two reaction mechanisms seem to be working simultaneously, i.e., a mechanism as postulated in monosilanes and a disproportionation reaction. These mechanisms are discussed.     

A new type of precursor for fibers in the system Si–C

Ceramic fibers with compositions in the system Si–C have a great potential for high-temperature applications. In recent years, our efforts have been dedicated to the development of polymers consisting of polysilanes suitable to spin fibers and build up matrices for CMC as well. The polysilanes are synthesized via disproportionation of the so-called disilane fraction [Richter, R., Roewer, G., Böhme, U., Busch, K., Babonneau, F., Martin, H.-P. et al., Appl. Organomet. Chem., 1997, 11, 71 (and references cited therein)]. A further thermal treatment yields materials which are soluble in organic solvents, and these solutions can be dry-spun to give fibers which are subsequently pyrolyzed. Solubility and high ceramic yield make this precursor a promising candidate for matrix infiltrations, too. The chemistry and the adjustment of viscosity and solubility to the requirements of the fiber processing as well as the conversion of the dried fibers to pure SiC fibers by thermal treatment will be reported.     

长链α-烯烃的硅氢加成反应研究

以聚三氟丙基乙烯基甲基硅氧烷为保护剂制备了102白色担体负载的铂络合物催化剂,用于催化长链α-烯烃与甲基二氯硅烷的硅氢加成反应。考察了铂催化剂用量、反应温度、不同长链烯烃原料、催化剂回收利用等因素对长链烷基甲基二氯硅烷收率的影响,结果表明,102白色担体负载的铂络合物催化剂对该硅氢加成反应具有较高的活性和稳定性,在常温下无需加热,无诱导期即可发生加成反应。在密闭体系中,1-十二烯烃与甲基二氯硅烷的摩尔比为1∶1.1,铂络合物与甲基二氯硅烷的摩尔比为6.5×10-5∶1时,十二烷基甲基二氯硅烷的收率可达88%;敞开体系中,相同条件下,十二烷基甲基二氯硅烷的收率可达77%。催化剂重复使用8次不失活。     

光氯化反应选择性脱除三氯氢硅中甲基二氯硅烷

研究采用连续流微通道反应器，利用光氯化反应选择性脱除三氯氢硅中的甲基二氯硅烷，考察各因素对甲基二氯硅烷去除率的影响。研究结果表明，增加氯气量和光强，升高温度，减少光源波长，延长反应时间有利于甲基二氯硅烷的去除，在最优条件下，产品中甲基二氯硅烷含量小于0.05?10-6，去除率达到99.6%；反应产物中出现少量四氯化硅，是聚氯硅烷和三氯氢硅发生氯化反应生成。以此为原料使用评价炉制备的多晶硅中碳含量小于3?1015atom/cm3，达到电子一级品指标。     

溶剂法醇解合成3,3,3-三氟丙基甲基二甲氧基硅烷

以3,3,3-三氟丙烯与甲基二氯硅烷催化合成3,3,3-三氟丙基甲基二氯硅烷。采用 溶剂法,以3,3,3-三氟丙基甲基二氯硅烷和甲醇为原料醇解合成3,3,3-三氟丙基甲基二甲氧基 硅烷。考察溶剂种类、原料配比、冷凝温度、填料大小等因素的影响,确立了最优合成条件。     

Homopolymerization and copolymerization of phenyltrichlorosilane by sonochemical reductive coupling in the presence of sodium

Summary Soluble polymers have been prepared by the sonochemical reductive coupling of phenyltrichlorosilane in toluene in the presence of sodium. Copolymers of phenyltrichlorosilane with phenylmethyldi-chlorosilane were synthesized. The obtained products are of relatively low molecular weight (ˉM_n<10,000). Investigations by ²⁹ Si NMR, UV and by the kinetic studies of the iodine addition indicate that polymers consist of fused cyclopolysilanes with 40% content of strained rings (probably four-membered). Homopolymerization and copolymerization of n-hexyl-trichlorosilane and methyltrichlorosilane is compared with that of phenyltrichlorosilane. The former monomer yields soluble homopolymer and copolymers of relatively higher molecular weights than phenyltrichlorosilane. Methyltrichlorosilane yields usually insoluble products and only at a concentration below 20%, were soluble copolymers formed.