CS209128B1 - n-octyldiphenylchlorosilane and a process for its preparation - Google Patents

Abstract

The invention addresses the preparation of one of the components for the production of highly active catalysts for the low-pressure polymerization of α-olefins, especially ethylene. The invention relates to the description of the hitherto unknown chemical compound n-octyldiphenylchlorosilane of the general formula (η-Οθ^γ)(CgHgJgSiCl and the method and conditions for its preparation by the reaction of diphenyldichlorosilane with n-octyllithium. The new individual is identified and characterized by chemical analysis, analysis of its infrared spectra and 1 2Q C and Si NMR spectra. Its basic physicochemical constants are determined. The compound can be further used for the synthesis of organosilicon compounds with an n-octyldiphenylsilyl group important for use in the field of polymer chemistry.

Description

The invention relates to a previously undescribed chemical compound n-octyldiphenylchlorosilane of the general formula (η-ΟθΗ,γ)(CgHjJgSiCl) and a method for its preparation.

Compounds of the general formula R^RgR^SiX , where R ₁ , R ₂ and Rj are organic substituents aliphatic, alicyclic or aromatic and X is an active inorganic easily interchangeable substituent such as halogen, QH-group or hydrogen, have recently gained considerable importance as intermediates in the synthesis of organosilicon esters of chromic acid, which serve as exceptionally active catalytic components in the low-pressure polymerization of ethylene. In addition to perphenylated silyl esters of chromic acid, alkyldiphenylsilyl esters have recently begun to be used with advantage. One of them is bis(n-octyldiphenylsilyl)ester of chromic acid, for the synthesis of which a suitable compound containing an n-octyldiphenylsilyl group is required as a starting material. The previously undescribed compound n-octyldiphenylchlorosilane has proven to be one of the most suitable compounds.

According to the invention, it is possible to synthesize n-octyldiphenylchlorosilane by converting diphenyldichlorosilane with n-octyllithium in an organic solvent environment, preferably hydrocarbons, according to the relationship (CgH ₅ ) ₂ SiCl ₂ + nC ₈ H ₁₇ Li --> (n-CgH, ?) (CgH^SiCl + LiGl

The reaction can be advantageously carried out in an environment of aliphatic saturated hydrocarbons with 5 to 7 carbon atoms in the molecule, especially pentane, because in them it is possible to easily and with a yield exceeding 75% of theory by reacting lithium sand and n-octyl chloride or n-octyl bromide to prepare n-octyllithium, which is used in the next stage for in situ conversion. The conversion takes place under inert gas at atmospheric pressure at temperatures of 45 to 80°C, preferably at the boiling point of the solvent used. The product is isolated after filtering off the lithium chloride by distilling off the solvent and vacuum rectification of the residue. The yield of n-octyldiphenylchlorosilane is 60% of theory.

The synthesis of the preparation is demonstrated by the following example.

Example

To a suspension of 21 g (3 mol) of lithium sand in 400 ml of n-pentane is added in small portions over the course of two hours 152 g (1.05 mol) of n-octyl chloride in 400 ml of the same solvent.

During the dosing period, the mixture is kept at a gentle boil by the reaction heat. After mixing the two components, the reaction mixture is heated for another two hours, then the solid unreacted portions are removed by filtration and 150 ml of diphenyldichlorosilane (0.70 mol) in 400 ml of n-pentane are added to the solution over the course of one hour. The mixture is kept at a gentle boil by the reaction heat, after the addition it is heated at this temperature for another hour. After cooling, the reaction mixture is filtered and the separated lithium chloride is washed with n-pentane. The combined n-pentane solutions are first freed of solvent, the oily residue is vacuum rectified. The main portion is converted under a pressure of 0.35 kPa at a temperature of 171 to 173°C. The yield is 144 g of a colorless oily product, which is 61.2 SL of theory.

The same product was obtained in a yield of 60 SL by the above procedure from n-octyl bromide in n-heptane.

171 to 173 C at a pressure of 0.35 kPa n§° = 1.5407

1014.3 kgm ^-3 (at 22.5°C)

Product properties and identification:

The product is a colorless oily liquid that is completely stable when dry.* In humid air, it smells of hydrogen chloride released by hydrolysis.

Boiling point

Refractive index

Specific gravity

Table I

Elemental analysis results for Cgo^^SiCl

Element content, % CHSiCl calculated found 72.58 8.22 8.49 10.71 72.60 9.20 8.32 10.67

Infrared spectrum.

The wavenumbers and absorption band assignments are given in Table II.

Table II

Infrared spectrum of n-octyldiphenylchlorosilane

abs.waist (cm ^-1 ) assignment abs.waist (cm“ ¹ ) assignment Explanations 445 m ^(C-H)Ph 1398 w V(C-C)Ph 48T with X-senz.Ph t429 with ý(C-C)Ph 521 V3 V(Si-CI) 1459 m J(CH ₃ )Ok Band intensities 552 m tf(C-C)Ph 1481 w V(C-C)Ph vs. - very strong 695 vs ý(C-C)Ph 1584 w V(C-C)Ph 3 - strong 707 with X-senz.Ph V(C-H)Ph 1760 vw comb. m - medium 742 pages . 1810 vw > . and hara. w - weak j((C-H)Ph 760 sh 1876 vw tf(C-H)Ph vw - very weak 909 vw ^(C-H)Ph 1948 vw sh - fold 993 m ^(C-H)Ph 2857 vs. 1,010 vw V(C-C)Ok 2870 ah > V(C-H)Ok 1,022 vw (l(C-H)Ph 2929 vs. 1072 vw (KC-H)Ph 2956 with Ph - phenyl 1114 vs. X-senz.Ph 3000 * Okay - n-octyl 1166 sh (J(C-H)Ph 3012 w X-sens. - sensitive strip 1173 w (i(C-H)Ph 3025 w > V(C-H)Ph to substitution 1269 W (l(C-H)Ok 3050 m 1299 w f>(C-H)Ph 3069 m 1340 w V(C-C)Ph 3082 sh ' 1374 w V(C-C)Ph

The infrared spectrum of n-octyldiphenylchlorosilane was obtained /on a Specord IR-75 instrument/ in the range 400 - 4000 cm” ¹ in a 0.05'mm KBr cell. The interpretation of the bands was carried out on the basis of vibrational analysis and comparison with the spectra of similar compounds, mainly triphenylchlorosilane, triphenylsilanol, n-octane and n-octanol. In the spectrum, it is possible to clearly identify the vibrations of the phenyl groups, octyl and the vibrations of Si-C and Si-Gl.

¹³ CpH}NMR and ²⁹ SiFn}NMR spectrum

The NMR spectrum of the compound was measured at a frequency of 25.00 MHz, ^{the 29} Si NMR spectrum at a frequency of 19.74 MHz. A 25% solution of the substance in deuteriochloroform with tetramethylsilane (TMS) as an internal standard was used for the measurement / ; J( ²⁹ Si) _TM g=0 /.

Measurements were performed at a temperature of 25°C. Chemical shift values are expressed in ppm.

NMR spectrum: δ(C ₁ ) = 133.86; α(Cg) - 134.30; ί(Ο^) = 128^06 ;

О(C ₄ ) = 130.40 ; η(CH ₂ Si) = 16.57; S(CH ₃ )·» 14.18 ;

< 5 < CH ₂ > = 33.09; 31.92; 29.24; 29.14; 23.00; 22.71.

²⁹ S ¹ h NMR spectrum: λ = +11.28

Structural formula of n-octyldiphenylchlorosilane:

13,

The C NMR spectrum clearly confirms the identity and predicted structure of the compound, while the ²⁹ Si NMR spectrum confirms the high degree of purity of the preparation.

Claims (2)

1) n-octyldiphenylchlorosilane of general formula (η-ΟθΗ ^ γ) (CgHgJgSiCl and structural formula 2) A process for the preparation of a compound according to item n-octyllithium in a medium 1 characterized in that diphenyldichlorosilane is left with organic solvents, preferably hydrocarbons. 2. A process according to claim 2, characterized in that saturated hydrocarbons having 5 to 7 carbon atoms, preferably n-pentane, are used as solvents.