CHEMISTRY

Corresponding Member of the Academy of Sciences of the USSR K. A. ANDRIANOV and N. A. KURASHEVA

ON THE HETEROFUNCTIONAL CONDENSATION REACTION OF BIS(TRIMETHYLSILOXY)DICHLOROTITANE WITH PHENYLMETHYLDIETHOXYSILANE

The heterofunctional condensation reaction of alkyl-(aryl)-halosilanes with alkyl-(aryl)-alkoxysilanes, proceeding according to the equation

[
\begin{gathered}
\begin{array}{cccccccccc}
& R & & & R_1 & & & R & & R_1 \
& | & & & | & & & | & & | \
\mathrm{Cl}-\mathrm{Si}-\mathrm{Cl}+\mathrm{C_2H_5O}-\mathrm{Si}-\mathrm{OC_2H_5}
\to
\mathrm{C_2H_5Cl}+\mathrm{Cl}-\mathrm{Si}-\mathrm{O}-\mathrm{Si}-\mathrm{OC_2H_5} \
& | & & & | & & & | & & | \
& R & & & R_1 & & & R & & R_1
\end{array}
\[1em]
\begin{array}{cccccccccccccc}
& R & & R_1 & & & R & & & R & & R_1 & & R \
& | & & | & & & | & & & | & & | & & | \
\mathrm{Cl}-\mathrm{Si}-\mathrm{O}-\mathrm{Si}-\mathrm{OC_2H_5}
+\mathrm{Cl}-\mathrm{Si}-\mathrm{Cl}
\to
\mathrm{C_2H_5Cl}
+\mathrm{Cl}-\mathrm{Si}-\mathrm{O}-\mathrm{Si}-\mathrm{O}-\mathrm{Si}-\mathrm{Cl} \
& | & & | & & & | & & & | & & | & & | \
& R & & R_1 & & & R & & & R & & R_1 & & R
\end{array}
\end{gathered}
]

and so on, has been studied in a number of examples and is used for the synthesis of both monomers and polymers ((^{1-3})). It was of definite interest to study the heterofunctional condensation reaction between alkyl-(aryl)-alkoxysilanes and bis(trimethylsiloxy)dichlorotitane. If this reaction proceeded according to the indicated scheme, one might expect the formation of linear polytitanorganosiloxanes. Condensation experiments of bis(trimethylsiloxy)dichlorotitane with phenylmethyldiethoxysilane at 150° showed that, in the course of the reaction, not ethyl chloride but trimethylchlorosilane is liberated, and a polymer is formed whose chemical composition corresponds to that written in equation I:

[
\mathrm{I.}\quad
2\,\mathrm{C_6H_5}
\overset{\mathrm{CH_3}}{\mathrm{Si}}
(\mathrm{OC_2H_5})_2
+
3\,\mathrm{Cl_2Ti}\left[\mathrm{OSi(CH_3)_3}\right]_2
\to
]

[
\to
-\left[
\begin{array}{cccccc}
& \mathrm{OSi(CH_3)_3} & \mathrm{CH_3} & \mathrm{OC_2H_5} & \mathrm{CH_3} & \mathrm{OC_2H_5} \
& | & | & | & | & | \
\mathrm{O} - \mathrm{Ti} - \mathrm{O} - \mathrm{Si} - \mathrm{O} - \mathrm{Ti} - \mathrm{O} - \mathrm{Si} - \mathrm{O} - \mathrm{Ti} - \
& | & | & | & | & | \
& \mathrm{Cl} & \mathrm{C_6H_5} & \mathrm{OC_2H_5} & \mathrm{C_6H_5} & \mathrm{Cl}
\end{array}
\right]_n
+
5\,\mathrm{(CH_3)_3SiCl}.
]

The polymer obtained by this reaction, readily soluble in benzene and toluene, is a highly elastic product at room temperature; on heating it can readily be drawn into threads, which become brittle under the action of atmospheric moisture.

Such a sharply different course of the reaction from the heterofunctional condensation of alkyl-(aryl)-halosilanes with alkyl-(aryl)-ethoxysilanes was the reason for a more thorough study of it. Investigation of this reaction showed that not only phenylmethyldiethoxysilane but also dimethyldibutoxysilane reacts with bis(trimethylsiloxy)dichlorotitane with liberation only of trimethylchlorosilane, and not butyl chloride, and with formation of a polymer. The chemical composition of the polymer obtained and the trimethylchlorosilane liberated, in amounts close to those given in equa-

compound I, shows that this reaction proceeds in a very complex manner. To study the reaction, investigations were carried out which showed that the reaction is caused by moisture, which interacts with bis-(trimethylsiloxy)-dichlorotitanium with evolution of hydrogen chloride:

[
\text{II.}\quad
1.\quad
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{TiCl}_2+\mathrm{H}_2\mathrm{O}\rightarrow \mathrm{HCl}+
\left[
\begin{array}{c}
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{Ti}
\begin{array}{c}
\mathrm{Cl}\[-2pt]
\diagup\[-2pt]
\diagdown\[-2pt]
\mathrm{OH}
\end{array}
\end{array}
\right].
]

The initial reaction product reacts with phenylmethyldiethoxysilane with evolution of alcohol:

[
2.\quad
\left[
\begin{array}{c}
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{Ti}
\begin{array}{c}
\mathrm{Cl}\[-2pt]
\diagup\[-2pt]
\diagdown\[-2pt]
\mathrm{OH}
\end{array}
\end{array}
\right]
+
\begin{array}{c}
\mathrm{CH}_3\
|\
\mathrm{C}_2\mathrm{H}_5\mathrm{O}-\mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5\
|\
\mathrm{C}_6\mathrm{H}_5
\end{array}
\rightarrow
]

[
\rightarrow
\begin{array}{ccccc}
& \mathrm{Cl} & & \mathrm{CH}_3 & \
& | & & | & \
(\mathrm{CH}_3)_3\mathrm{SiO} & - & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5 \
& | & & | & \
& \mathrm{OSi}(\mathrm{CH}_3)_3 & & \mathrm{C}_6\mathrm{H}_5 &
\end{array}
+\mathrm{C}_2\mathrm{H}_5\mathrm{OH},
]

and hydrogen chloride reacts with the trimethylsiloxane group bound to titanium, with formation of trimethylchlorosilane:

[
3.\quad
\begin{array}{ccccc}
& \mathrm{Cl} & & \mathrm{CH}_3 & \
& | & & | & \
(\mathrm{CH}_3)_3\mathrm{SiO} & - & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5 \
& | & & | & \
& \mathrm{OSi}(\mathrm{CH}_3)_3 & & \mathrm{C}_6\mathrm{H}_5 &
\end{array}
+\mathrm{HCl}
\rightarrow
(\mathrm{CH}_3)_3\mathrm{SiCl}
+
]

[
+
\left[
\begin{array}{ccccc}
& \mathrm{Cl} & & \mathrm{CH}_3 & \
& | & & | & \
(\mathrm{CH}_3)_3\mathrm{SiO} & - & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5 \
& | & & | & \
& \mathrm{OH} & & \mathrm{C}_6\mathrm{H}_5 &
\end{array}
\right].
]

The alcohol reacts, as is shown by the composition of the polymer and of the low-molecular-weight derivatives obtained, with trimethylchlorosilane, with formation of trimethylethoxysilane, which was also isolated in small amounts:

[
4.\quad
(\mathrm{CH}_3)_3\mathrm{SiCl}+\mathrm{C}_2\mathrm{H}_5\mathrm{OH}
\rightarrow
(\mathrm{CH}_3)_3\mathrm{SiOC}_2\mathrm{H}_5+\mathrm{HCl}
]

[
5.\quad
\begin{array}{ccccc}
& \mathrm{Cl} & & \mathrm{CH}_3 & \
& | & & | & \
(\mathrm{CH}_3)_3\mathrm{Si} & -\mathrm{O}- & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5 \
& & | & & | \
& & \mathrm{OSi}(\mathrm{CH}_3)_3 & & \mathrm{C}_6\mathrm{H}_5
\end{array}
+\mathrm{C}_2\mathrm{H}_5\mathrm{OH}
\rightarrow
]

[
\rightarrow
\begin{array}{ccccc}
& \mathrm{OC}_2\mathrm{H}_5 & & \mathrm{CH}_3 & \
& | & & | & \
(\mathrm{CH}_3)_3\mathrm{SiO} & - & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}-\mathrm{OC}_2\mathrm{H}_5 \
& | & & | & \
& \mathrm{OSi}(\mathrm{CH}_3)_3 & & \mathrm{C}_6\mathrm{H}_5 &
\end{array}
+\mathrm{HCl}
]

[
6.\quad
\left[
\begin{array}{ccccc}
& \mathrm{CH}_3 & & \mathrm{Cl} & \
& | & & | & \
\mathrm{C}_2\mathrm{H}_5\mathrm{O} & -\mathrm{Si}-\mathrm{O}- & \mathrm{Ti} & - & \mathrm{OH} \
& | & & | & \
& \mathrm{C}_6\mathrm{H}_5 & & \mathrm{OSi}(\mathrm{CH}_3)_3 &
\end{array}
\right]
+
\begin{array}{ccccc}
& \mathrm{CH}_3 & & \mathrm{OC}_2\mathrm{H}_5 & \
& | & & | & \
\mathrm{C}_2\mathrm{H}_5\mathrm{O} & -\mathrm{Si}-\mathrm{O}- & \mathrm{Ti} & - & \mathrm{OSi}(\mathrm{CH}_3)_3 \
& | & & | & \
& \mathrm{C}_6\mathrm{H}_5 & & \mathrm{OSi}(\mathrm{CH}_3)_3 &
\end{array}
\rightarrow
]

[
\rightarrow
\mathrm{C}_2\mathrm{H}_5\mathrm{OH}
+
\begin{array}{ccccccccc}
& \mathrm{CH}_3 & & \mathrm{Cl} & & \mathrm{CH}_3 & & \mathrm{OC}_2\mathrm{H}_5 & \
& | & & | & & | & & | & \
\mathrm{C}_2\mathrm{H}_5\mathrm{O} & -\mathrm{Si}-\mathrm{O}- & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si} & -\mathrm{O}- & \mathrm{Ti} & -\mathrm{O}- & \mathrm{Si}(\mathrm{CH}_3)_3 \
& | & & | & & | & & | & \
& \mathrm{C}_6\mathrm{H}_5 & & \mathrm{OSi}(\mathrm{CH}_3)_3 & & \mathrm{C}_6\mathrm{H}_5 & & \mathrm{OSi}(\mathrm{CH}_3)_3 &
\end{array}
]

The alcohol and hydrogen chloride liberated in the course of the reaction react further with formation of trimethylchlorosilane, trimethylethoxysilane, and a polymer of the composition given above. To confirm these reactions, experiments were carried out with bis-(trimethylsiloxy)-dichlorotitanium with small amounts of water and hydrogen chloride. In the reaction of bis-(trimethylsiloxy)-dichlorotitanium with water, 0.01 mole of water was taken per mole of bis-(trimethylsiloxy)-dichlorotitanium. The reaction was accompanied by formation of trimethylchlorosilane (about 50%) and of a nonvolatile polymer, insoluble in organic solvents, containing about 50% inorganic portion. This experiment shows that bis-(trimethylsiloxy)-dichlorotitanium is converted into a polymer even in the presence of an insignificant amount of water. This may be represented by the following reaction scheme:

$$
\text{III.}\quad
1.\quad
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{TiCl}_2 + \mathrm{H_2O}
\rightarrow
\left[
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{Ti}
\begin{matrix}
\mathrm{Cl}\[-2pt]
\diagup\[-2pt]
\diagdown\[-2pt]
\mathrm{OH}
\end{matrix}
\right]
+ \mathrm{HCl}
$$

$$
2.\quad
2\left[
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{Ti}
\begin{matrix}
\mathrm{Cl}\[-2pt]
\diagup\[-2pt]
\diagdown\[-2pt]
\mathrm{OH}
\end{matrix}
\right]
\rightarrow
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{Ti}
\begin{matrix}
\mathrm{Cl}\[-2pt]
|\[-2pt]
\end{matrix}
-\mathrm{O}-
\begin{matrix}
\mathrm{OH}\[-2pt]
|\[-2pt]
\end{matrix}
\mathrm{Ti}[\mathrm{OSi}(\mathrm{CH}_3)_3]_2
+ \mathrm{H_2O}
$$

$$
3.\quad
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2
\begin{matrix}
\mathrm{Cl}\[-2pt]
|\[-2pt]
\end{matrix}
\mathrm{Ti}
-\mathrm{O}-
\begin{matrix}
\mathrm{OH}\[-2pt]
|\[-2pt]
\end{matrix}
\mathrm{Ti}[\mathrm{OSi}(\mathrm{CH}_3)_3]_2
+ \mathrm{HCl}
\rightarrow
(\mathrm{CH}_3)_3\mathrm{SiCl}
+
\mathrm{HO}-
\begin{matrix}
\mathrm{Cl}\[-2pt]
|\[-2pt]
\mathrm{Ti}\[-2pt]
|\[-2pt]
\mathrm{OSi}(\mathrm{CH}_3)_3
\end{matrix}
-\mathrm{O}-\cdots
$$

To confirm reaction (III)3, the interaction of bis-(trimethylsiloxy)-dichlorotitanium with hydrogen chloride was investigated, and it was found that under the action of hydrogen chloride trimethylchlorosilane and a polymer are formed:

$$
[(\mathrm{CH}_3)_3\mathrm{SiO}]_2\mathrm{TiCl}_2 + \mathrm{HCl}
\rightarrow
(\mathrm{CH}_3)_3\mathrm{SiCl} + \text{polymer}.
$$

Experimental Part

I. Condensation of bis-(trimethylsiloxy)-dichlorotitanium with phenylmethyldiethoxysilane.

A mixture of 27.33 g (0.092 mole) of bis-(trimethylsiloxy)-dichlorotitanium (b.p. 73°/3 mm, Cl 24.16%) and 19.3 g (0.092 mole) of phenylmethyldiethoxysilane (b.p. 69–70°/3 mm, (n_D^{20}) 1.4690) was heated for 4.5 hours in a Favorskii flask at 150°. During this time, 6.7 g of substance was distilled off at 60–63°. The remaining pot residue was subjected to vacuum distillation. During vacuum distillation, 4.63 g of the initial phenylmethyldiethoxysilane, amounting to 24% of that taken into the reaction, was distilled off at 70–71°/3 mm with (n_D^{20}) 1.4690. In the trap there remained 3.8 g; the pot residue was 25.0 g (84.6%), a yellow polymer which, on heating, can be drawn into threads and is brittle in air. All the low-boiling liquid was distilled on a column, and 3 fractions were isolated.

I fraction: 58°; 8.32 g of trimethylchlorosilane with Cl content 31.93%, 32.06%; calculated Cl 32.6%. Literature data: b.p. 57°.

II fraction: 62–71°; 4.8 g of a mixture of trimethylchlorosilane and trimethylethoxysilane.

III fraction: 74–76°; 1.8 g of trimethylethoxysilane, (n_D^{20}) 1.3748. Literature data: b.p. 75°, (n_D^{20}) 1.3741.

For trimethylethoxysilane, Si found 23.72%, 23.48%; calculated Si 23.72%.

Analysis of the polymer for:

[
-\left[
\begin{array}{cccccccc}
& \mathrm{OSi(CH_3)_3} & \mathrm{CH_3} & & \mathrm{OC_2H_5} & \mathrm{CH_3} & & \mathrm{OC_2H_5} \
& | & | & & | & | & & | \
\mathrm{O}—\mathrm{Ti}—\mathrm{O}—\mathrm{Si}—\mathrm{O}—\mathrm{Ti}—\mathrm{O}—\mathrm{Si}—\mathrm{O}—\mathrm{Ti}— \
& | & | & & | & | & & | \
& \mathrm{Cl} & \mathrm{C_6H_5} & & \mathrm{OC_2H_5} & \mathrm{C_6H_5} & & \mathrm{Cl}
\end{array}
\right]_n
]

Found, %: C 35.97; 36.07; H 5.06; 5.04; Cl 9.12; 9.06; ash 54.3; 54.4
Calculated, %: C 36.30; H 5.25; Cl 9.32; ash 55.40

II. Condensation of bis(trimethylsiloxy)dichlorotitanium with dimethyldibutoxysilane. From 19.7 g (0.066 mole) of bis(trimethylsiloxy)dichlorotitanium (b.p. 73°/3 mm, Cl 24.16%) and 13.5 g (0.066 mole) of dimethyldibutoxysilane (b.p. 187°, (n_D^{20}) 1.4058), under analogous conditions there were obtained 14.3 g of a polymer, a product that was opaque and highly viscous at room temperature; 2.33 g of the starting dimethyldibutoxysilane (17.3% of that taken into the reaction), which separated on vacuum distillation at 50°/3 mm, (n_D^{20}) 1.4050; and 13.2 g of a low-boiling liquid which, on distillation through a column, gave three fractions:

I fraction: 58°; 6.7 g of trimethylchlorosilane; found Cl 33.06%, 33.25%; calculated Cl 32.6%. Literature data: b.p. 57°.

II fraction: 64–120°; 1.9 g of a mixture of trimethylchlorosilane and trimethylbutoxysilane.

III fraction: 122–124.5°; 3.0 g of trimethylbutoxysilane; found (n_D^{20}) 1.3919; (d_{20}^{4}) 0.7779. Literature data: (n_D^{20}) 1.3925; (d_{20}^{4}) 0.7774. B.p. 124.5°.

III. Reaction of bis(trimethylsiloxy)dichlorotitanium with water. A Favorskii flask with a very high dephlegmator was charged with 8.3 g (0.028 mole) of bis(trimethylsiloxy)dichlorotitanium (b.p. 73°/3 mm, Cl 24.6%) in 45 ml of dry dioxane and 0.0044 g of (\mathrm{H_2O}) (0.00028 mole) in 5 ml of dioxane. The mixture was heated, and after an hour liquid began to distill at a temperature of 60°; 4.6 g (66% of theory) with 32.5% Cl was distilled. For trimethylchlorosilane: b.p. 57°, Cl 32.6%. After removal of the dioxane, a dry gray powder remained in the flask (3.9 g), insoluble in organic solvents, containing 55.0% inorganic part and 15.7% chlorine. The trimethylchlorosilane obtained (2.12 g) was hydrolyzed, washed, dried, and after distillation 1 g (65% of theoretical) of hexamethyldisiloxane was isolated at 100°, (n_D^{20}) 1.3740. Literature data: b.p. 100°, (n_D^{20}) 1.3722.

IV. Reaction of bis(trimethylsiloxy)dichlorotitanium with hydrogen chloride. Dry hydrogen chloride was passed for 4 h through 11.1 g (0.037 mole) of bis(trimethylsiloxy)dichlorotitanium. The transparent solution of bis(trimethylsiloxy)dichlorotitanium turned yellow and thickened. The resulting reaction mixture was distilled. At 58°, 3.9 g (45% of theoretical) of trimethylchlorosilane was isolated; found Cl 33.2%; 33.1%; calculated Cl 32.6%; in the still residue was a polymer—a solid substance of dark color.

Institute of Organoelement Compounds
Academy of Sciences of the USSR

Received
6 VII 1960

CITED LITERATURE

1. N. N. Sokolov, K. A. Andrianov, Izv. AN SSSR, OKhN, 1957, No. 7, 806.
2. K. A. Andrianov, N. N. Sokolov, E. N. Khrustaleva, ZhOKh, 26, 1102 (1956).
3. K. A. Andrianov, N. N. Sokolov, G. N. Ganina, ZhOKh, 26, 1691 (1956).