RU2125579C1 - Polycarbosilanes containing metallic clusters and process for preparing thereof - Google Patents

Abstract

FIELD: organic chemistry. SUBSTANCE: present invention describes polycarbosilanes containing metallic clusters of general formula:

wherein n is equal or more than 6; m is 0.001-1; R¹,R²,R³ are CH₃, C₂H₅, -CH=CH₂ and -CH₂CH=CH₂; Cl are clusters of III-VIII group transition metals. Said polycarbosilanes are useful for preparing highly strong heat-resistant composite ceramic materials. Coordination compounds of III-VIII group transition metals are reacted at 150-450 C with silanes of general formula (2) or (3) or with carbosilanes of general formula (4) or with mixtures thereof. If desired, reaction mixture is maintained at 150-450 C for 0.5-5 hours on addition of metallic compounds. In formula (2), (3) and (4) a is equal or more than 2, b is equal or more than 4, K is 0-10, r is 1-10;
R¹,R²SiR³R⁴

R,R¹,R²,R³,R⁴ are H,-CH₃,-C₂H ₅,-CH=CH₂,-CH₂-CH=CH₂. EFFECT: improved properties of the title compounds. 3 cl, 1 ex, 2 tbl

Description

где n ≥ 6, m = 0,001 - 1;
R¹, R² , R³ = -CH₃, -C₂H₅, -C₆H₅, -CH=CH₂, -CH₂CH=CH₂;
Кл - кластеры переходных металлов III-VIII групп.The invention relates to the field of production of polycarbosilanes (PCB), specifically, to the field of production of polycarbosilanes containing metal clusters, of the general formula

where n ≥ 6, m = 0.001 - 1;
R ¹ , R ² , R ³ = —CH ₃ , —C ₂ H ₅ , —C ₆ H ₅ , —CH = CH ₂ , —CH ₂ CH = CH ₂ ;
Cl - clusters of transition metals of groups III-VIII.

 Organosilicon polymers of the polycarbosilane class are mainly used as raw materials for the production of high-strength heat-resistant composite ceramics. To maintain the strength of ceramics at high temperatures, the metal should be distributed as evenly as possible in the ceramic phase, almost at the molecular level, and, in addition, oxygen should be excluded from the composition of the ceramic phase.

 The presence of a uniformly distributed chemically bound metal in the PCB matrix stabilizes the homogeneous ultrafine microstructure of SiC ceramics with high thermomechanical properties. Such metal-filled PCBs can also significantly expand the scope of SiC ceramics, since they can be used to produce films, coatings, binders, impregnating compositions, as well as for processing powders, fibers, matrices, and other components of heat-resistant composite ceramic materials into SiC. Substances of this type can also be used as polymer and ceramic compositions with specific electrical and magnetic properties.

 The present invention allows for the most uniform distribution of metal in the polymer, without the participation of oxygen due to the introduction of metal nanoparticles in cluster form.

 Cluster polycarbosilanes (ClPKS) are transparent, viscous or solid products from light yellow to dark brown, readily soluble in aromatic hydrocarbons: carbon tetrachloride, chloroform, tetrahydrofuran, dioxane, hexane and other saturated hydrocarbons.

 KlPKS of the specified general formula, its structure, physicochemical properties and the method of preparation are not described in the literature.

A known method for producing PCD using anhydrous metal halides of groups II-VIII (MHaI _n ), mainly Al, Ti, V, Cr, Mn, Co or mixtures thereof, taken in an amount of 1-5 wt.% By thermal decomposition of polydimethylsilane at a temperature of 350-470 ^o C and atmospheric pressure (US Pat. UK 210665528, 1983).

 This method does not allow to obtain polycarbosilanes containing metals, since metal halides, playing the role of catalysts for the polycondensation process, do not chemically bind to the polymer, but precipitate in the form of insoluble reaction products. In addition, the process is distinguished by the duration, multi-stage, as well as the need to use high temperatures.

 The closest in technical essence to the proposed invention and adopted as a prototype is a method for producing polytitanium or polyzirconocarbosilane, partially containing metalloxane units (Pat. 30105 EPO, 1980).

или

где M = Ti, Zr.

or

where M = Ti, Zr.

 The polymers are obtained by prolonged heat treatment of polydimethylsilane in an inert atmosphere in the presence of tetrabutoxy titanium, tetrabutoxy zirconium or polytitan diphenyl siloxane.

 The disadvantage of this method is the presence of oxygen atoms in the main and side chains of macromolecules, which adversely affects the oxidative and thermal stability of products from silicon carbide.

 The objective of the invention is to obtain polycarbosilanes containing metal clusters of the general formula (I).

где a ≥ 2, b ≥ 4, r = 1-10, R, R¹, R², R³, R⁴-H, -CH₃, -C₂H₅, -C₆H₅, -CH=CH₂, -CH₂-CH=CH₂.The technical result is achieved by the fact that polycarbosilanes containing metal clusters of the general formula (I) are obtained. These substances are prepared as follows: the initial mass containing silanes and / or carbosilanes is reacted with metal-containing compounds or mixtures thereof at 150-450 ^° C. and silanes of the general formula (2) or (3) and / or carbosilanes of the general formula (4) are used )
R ¹ R ² SiR ³ R ⁴ (2)

where a ≥ 2, b ≥ 4, r = 1-10, R, R ¹ , R ² , R ³ , R ⁴ -H, -CH ₃ , -C ₂ H ₅ , -C ₆ H ₅ , -CH = CH ₂ , —CH ₂ —CH = CH ₂ .

In some cases, to achieve the required degree of polycondensation of CLCP, the reaction mass is additionally heated at a temperature of 150 - 450 ^o C for 0.5 - 5 hours. When heated at a temperature below 150 ^o C or less than 0.5 hours, the reaction does not occur, at a temperature above 450 ^o C or with an increase in heating time more than 5 hours, coke-like insoluble products are formed.

The essence of the invention is as follows: coordination compounds of metals are preferably introduced in an amount of 0.1-10% by weight of the starting mixture at a temperature exceeding 50 ^o C, but not higher than 450 ^o C. When adding the compound in amounts of less than 0.1 wt.% the effect of the introduction of the metal is negligible, with the addition of more than 10 wt.% in the synthesis process, the formation of insoluble by-products.

 During the tests, coordination compounds of transition metals of groups III - VIII were used, such as Ti, Zr, Hf, V, Fe, Ni, Co, Cr, W, Mo, Mn, Re, Pt, Pd, Rh, B with organic, carbonyl, carbollyl, dialkyl (aryl) amide, trialkyl (aryl) silyl, bis [hexaalkyl (aryl) disilyl] amide and other ligands. In addition to this list, mixed, bi- and multicore complexes can be used, as well as any coordination compounds of metals, except those in which there are direct metal-oxygen bonds.

Examples of metal-containing compounds used can be [C ₅ (CH ₃ ) ₅ ] ₂ TiCl ₂ , (C ₅ H ₅ ) ₂ ZrCl ₂ , (CH ₃ C ₅ H ₄ ) ₂ HfBr ₂ , Fe (CO) ₅ , Fe ₃ ( CO) ₁₂ , Fe ₂ (CO) ₉ , π -C ₃ H ₅ Fe (CO) ₃ Cl, [(C ₅ H ₅ ) Fe (CO) ₂ ] ₂ , π -C ₃ H ₅ Co (CO) ₃ , Co (C ₅ H ₅ ) ₂ ,
C ₅ H ₅ Co (CO) ₂ , Co (CO) ₈ , Ni (CO) ₄ , [C ₅ H ₅ Ni (CO)] ₂ , (C ₃ H ₅ ) ₂ Ni, (C ₅ H ₅ ) ₂ Ni, (CH ₃ C ₆ H ₄ ) ₂ Cr, CH ₃ C ₅ H ₄ Cr (CO) ₃ , Cr (CO) ₆ , W (CO) ₆ , (CH ₃ C ₆ H ₄ ) ₂ W, C ₃ H ₅ MoC ₅ H ₅ (CO) ₂ , C ₃ H ₅ Mn (CO) ₄ , (C ₃ H ₅ ) ₂ Pd, C ₃ H ₅ PdC ₅ H ₅ , C ₃ H ₅ RhC ₅ H ₅ , C ₅ H ₅ Rh (CO) ₂ , (CH ₃ ) ₄ Pt, C ₃ H ₅ PtC ₅ H ₅ Ti (CH ₂ C ₆ H ₅ ) ₄ , Zr (CH ₃ ) ₄ ,
Ti [N (CH ₃ ) ₂ ] ₄ Zn {N [Si (CH ₃ )] ₂ } ₂ , etc.

 The introduction of complexes or their mixtures into the reaction mass, consisting of mono- (2) or polysilanes (3) and / or carbosilanes (4), allowed in all cases to obtain positive results. This confirms the validity of the volume of claims.

(1050 и 1350 см^-1) звеньев, боковыми заместителями при атомах кремния являются гидридные

SiH (2100 см^-1) и метильные

Si -CH₃ (1250 и 1400 см^-1), а в ряде случаев фенильные

Si - Ph (1480 см^-1) и винильные

Si -CH=CH₂ (1600 см^-1) группы. Получаемые полимеры по данным ЯМР ²⁹(Si) спектроскопии имеют соотношение HSiC₃ и SiC₄ групп ( σ -16 м.д. и 0 м.д. соответственно), близкое к единице, что свидетельствует о регулярности строения КлПКС. Металл присутствует в полимере в виде кластерных частиц (5 -80

), определенных методом рентгеновского малоуглового рассеяния, в количествах 0,1 - 10 мас.% Средняя молекулярная масса КлПКС по данным гельпроникающей хроматографии составляет 1200 - 2500. Во время синтеза КлПКС не образует побочных нерастворимых продуктов, что позволяет не применять операции растворения, фильтрации, отгонки растворителя. КлПКС проявляет хорошо выраженную способность к волокнообразованию, легко отверждается при термохимической обработке, дает высокий выход керамического SiC остатка.According to IR spectroscopy, the main skeleton of CLCP consists of

(1050 and 1350 cm ^-1 ) units, side substituents at silicon atoms are hydride

SiH (2100 cm ^-1 ) and methyl

Si-CH ₃ (1250 and 1400 cm ^-1 ), and in some cases phenyl

Si - Ph (1480 cm ^-1 ) and vinyl

Si —CH = CH ₂ (1600 cm ⁻¹ ) groups. The obtained polymers according to NMR ²⁹ (Si) spectroscopy have a ratio of HSiC ₃ and SiC ₄ groups (σ -16 ppm and 0 ppm, respectively) close to unity, which indicates the regularity of the structure of CLCP. The metal is present in the polymer in the form of cluster particles (5 -80

), determined by the method of small angle X-ray scattering, in amounts of 0.1 - 10 wt.%. The average molecular weight of CLPKS according to gel permeation chromatography is 1200 - 2500. During the synthesis of CLPKS does not form side insoluble products, which allows not to use the operation of dissolution, filtration, distillation of the solvent. CpPCS exhibits a well-defined ability to fiber formation, is easily cured by thermochemical treatment, and gives a high yield of ceramic SiC residue.

 The introduction of coordination compounds into the preheated reaction mixture allows not only to improve the quality of the ceramic-forming polymer, but also to accelerate the processes of rearrangement and polycondensation of the starting reagents.

 The invention is illustrated by the following examples.

 Example 1

, соотношение HSiC₃ и SiC₄ групп равно 0,95. Выход неорганического продукта после термообработки полимера в инертной атмосфере до 1100^oC составляет 65 мас.%, содержание железа в SiC керамике 1% масс, кислорода не более 0,1 мас.%.The apparatus, equipped with a stirrer, a thermocouple, a metering funnel, a reflux condenser, a nozzle with a direct cooler for removal of solvent and low molecular weight synthesis products, is filled with inert gas and 100 g of a mixture of oligomeric products (OP) obtained as a result of thermal decomposition of polydimethylsilane, which are a mixture, are loaded into it including silanes of formula 3 (a = 2 - 7, b = 5, 6, R ¹ -R ⁴ = H, -CH ₃ , R = H) and carbosilanes of formula 4 (k = 2 - 3, r = 2 - 4 ) with M _p = 300 - 500. The reaction mixture is heated to 250 ^° C and 1 g of Fe (CO) ₅ is added over a period of 0.5 hours in the form of a 3% solution and in hexane. Then the reaction mass is cooled in a stream of inert gas and unload 70 g of polymer with M _p = 1800 and softening temperatures (T ^o size.) 150 - 160 ^o C and fiber formation (T ^o w / o) 200 - 220 ^o C. The iron content in the polymer is 0.5 wt.%, the cluster size is 50

, the ratio of HSiC ₃ and SiC ₄ groups is 0.95. The output of the inorganic product after heat treatment of the polymer in an inert atmosphere up to 1100 ^o C is 65 wt.%, The iron content in the SiC ceramic is 1% by mass, oxygen is not more than 0.1 wt.%.

 Other examples are given in table 1.

 The advantages of the invention are apparent from a comparison of the properties of ClPCS and polytitanocarbosilane obtained by a known method (see table 2).

), образующие прочные связи с полимерной матрицей и практически не содержат кислород, что дает возможность использовать их для получения жаропрочной окислительной керамики на основе стабилизированного мелкокристаллического карбида кремния. Синтезированные полимеры и неорганические материалы на их основе могут найти также применение в электронной и химической промышленности благодаря специфическим электромагнитным и каталитическим свойствам.Thus, obtained according to the proposed invention, CLPKS are fusible soluble polymers of regular structure, easily processed into products of various shapes and forming a ceramic phase in high yield. KlPKS contain uniformly distributed metal nanoparticles (size 5-80

), forming strong bonds with the polymer matrix and practically do not contain oxygen, which makes it possible to use them to obtain heat-resistant oxidizing ceramics based on stabilized fine crystalline silicon carbide. Synthesized polymers and inorganic materials based on them can also find application in the electronic and chemical industries due to specific electromagnetic and catalytic properties.

Claims (2)

1. Polycarbosilanes containing metal clusters of the general formula

where n ≥ 6;
m = 0.001 to 1;
R ¹ , R ² , R ³ = —CH ₃ , —C ₂ H ₅ , —C ₆ H ₅ , —CH = CH ₂ , —CH ₂ CH = CH ₂ ,
Cl clusters of transition metals III - VIII of the group of average mol. M. 1200 - 2500. 2. A method of producing polycarbosilanes of the formula (1), characterized in that the initial mass containing silanes of the general formula (2) or (3) and / or carbosilanes of the general formula (4)

or cyclo

or cyclo

where a ≥ 2;
b ≥ 4;
k is 0-10;
r is 1 to 10;
R, R ¹ , R ² , R ³ , R ⁴ = H, -CH ₃ , -C ₂ H ₅ , -C ₆ H ₅ , -CH = CH ₂ , -CH ₂ CH = CH ₂ ,
subjected to interaction with coordination compounds of metals or their mixtures at 150 - 450 ^o C.

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