Synthesis of trichlorosilane from tetrachlorosilane and hydridosilanes

1. A process for the preparation of trichlorosilane (HSiCl 3 ) comprising reacting tetrachlorosilane (SiCl 4 ) with at least one hydridosilane in the presence of at least one catalyst, wherein the hydridosilanes are selected from the group consisting of MeSiH 3 , Me 3 SiH, Me 2 SiH 2 , Et 2 SiH 2 , Me 2 SiHCl, PhSiH 3 , Ph 2 SiH 2 , PhMeSiH 2 , iPr 2 SiH 2 , Hex 2 SiH 2 , tBu 2 SiH 2 , Me 2 Si(OEt)H, ViSiH 3 , ViMeSiH 2 , Me 2 HSi—SiHMe 2 , MeH 2 Si—SiH 2 Me, MeH 2 Si—SiHMe 2 , Me 3 Si—SiHMe 2 , and Me 3 Si—SiH 2 Me.

2. A process for the preparation of trichlorosilane (HSiCl 3 ) comprising reacting tetrachlorosilane (SiCl 4 ) with at least one hydridosilane in the presence of at least one catalyst, wherein the at least one catalyst is selected from the group consisting of:

one or more compounds of the formula R 1 4 QZ, wherein R 1 is independently chosen from hydrogen or an organyl group, Q is nitrogen, arsenic, antimony or bismuth, and Z is halogen,

one or more phosphines of the formula R 1 3 P, wherein R 1 is as defined above,

one or more alkali metal halides, and

one or more an alkaline earth metal halides.

3. The process of claim 1 , comprising reacting tetrachlorosilane with dimethylsilane according to the reaction equations (I) or (II):

Me 2 SiH 2 +2 SiCl 4 →2 HSiCl 3 +Me 2 SiCl 2   (I),

Me 2 SiH 2 +SiCl 4 →HSiCl 3 +Me 2 SiHCl  (II).

4. The process according to claim 1 , which is carried out at a temperature in the range of about −40° C. to about 250° C.

5. The process according to claim 1 , which is carried out at a pressure from about 0.1 to about 10 bar.

6. The process according to claim 1 , which is carried out under inert conditions.

7. A process for the preparation of trichlorosilane (HSiCl 3 ) comprising reacting tetrachlorosilane (SiCl 4 ) with at least one hydridosilane in the presence of at least one catalyst, wherein the at least one hydridosilane is selected from the group consisting of formulae:

R n SiX m H 4-n-m   (1),

and

R o Si 2 X p H 6-o-p   (2),

wherein

R is an organic group,

X is halogen or alkoxy,

n is 0 to 3,

m is 0 to 2, and

n+m=0 to 3,

o is 0 to 5,

p is 0 to 5, and

o+p=1 to 5

further comprising hydrogenating the resulting chlorosilanes to hydridosilanes of the formulae (1) or (2), and recycling said hydridosilanes into the reaction with tetrachlorosilane.

8. The process according to claim 7 , which is carried out in the presence of R 1 4 QZ, wherein R 1 is an organyl group, Q is nitrogen, and Z is chlorine.

9. The process according to claim 7 , which is carried out in the presence of at least one solvent.

10. The process according to claim 7 , wherein the hydrogenating step is carried out with at least one hydrogenation agent selected from the group consisting of metal hydrides.

11. The process according to claim 1 , which comprises

A) reacting tetrachlorosilane with dimethylsilane according to the reaction equation (I) or (II):

Me 2 SiH 2 +2 SiCl 4 →2 HSiCl 3 +Me 2 SiCl 2   (I)

Me 2 SiH 2 +SiCl 4 →HSiCl 3 +Me 2 SiHCl  (II),

in the presence of a catalyst of the formula R 1 4 QZ, wherein R 1 is an organyl group, Q is phosphorus or nitrogen, and Z is chlorine,

B) separating the HSiCl 3 and Me 2 SiCl 2 or Me 2 SiHCl from the reaction mixture,

C) hydrogenating the Me 2 SiCl 2 or Me 2 SiHCl or part thereof (which means that not the entire amount of Me 2 SiCl 2 or Me 2 SiHCl is subjected to hydrogenating) with at least one metal hydride, to form Me 2 SiH 2 ,

D) recycling the Me 2 SiH 2 , into step A).

12. The process according to claim 1 , wherein the selectivity of the formation of HSiCl 3 , defined as

Molar amount of HSiCl 3 formed/molar amounts of all hydrogenated silanes formed (ΣH 1-4 SiCl 0-3 , wherein the sum of number of hydrogen atoms and chlorine atoms adds up to 4)×100

is at least about 90%.

13. The process according to claim 1 , wherein the molar ratios of the at least one hydridosilanes to tetrachlorosilane (SiCl 4 ) is in the range of about 0.05 to about 2.

14. The process according to claim 1 ,

wherein the at least one hydridosilane is formed in situ from chlorosilanes and LiH.

15. The process according to claim 1 , which is carried out in the absence of at least one solvent.

16. The process according to claim 7 , wherein the hydrogenating step is carried out with at least one hydrogenation agent chosen from LiAlH 4 , LiH, CaH 2 or LiH which is formed in situ by admixture of LiCl and NaH, and subsequently heating said mixture resulting from the admixture of LiCl and NaH to a temperature in the range of about 60° C. to about 200° C.

17. The process according to claim 7 , wherein R is chosen from a C1 to C6 alkyl group, and X is chlorine or bromine.