Hexamethyldisiloxane → TRIS(TRIMETHYLSILOXY)CHLOROSILANE

HRID 1085978Notes

Reaction equation

HRID 1085978 reaction equation
C[Si](C)(C)[O:3][Si:4]([CH3:7])([CH3:6])[CH3:5].Cl[Si:11]([Cl:14])(Cl)Cl>C(Cl)Cl.CN(C)C(=O)N(C)C>[Cl:14][Si:11]([O:3][Si:4]([CH3:5])([CH3:6])[CH3:7])([O:3][Si:4]([CH3:7])([CH3:6])[CH3:5])[O:3][Si:4]([CH3:7])([CH3:6])[CH3:5]

Participants

5

Reactant 2

HCID 24764HexamethyldisiloxaneHCID 24816Silicon tetrachloride

Product 1

HCID 2760882TRIS(TRIMETHYLSILOXY)CHLOROSILANEYield 27%

Reagents, catalysts & solvents 2

HCID 12437TetramethylureaCatalystHCID 6344DichloromethaneSolvent

Procedure

About 4.6 g (0.2% by weight) of tetramethylurea and 183.4 g of a 25% solution of phosphonitrile chloride in methylene chloride are added to a mixture containing 1707 g (10.5 mol) of hexamethyldisiloxane and 595 g (3.5 mol) of tetrachlorosilane with stirring in a 4 liter multineck flask fitted with internal thermometer, stirrer and a reflux condenser. The reaction temperature is kept at 45° C. by cooling. After 21 hours, the volatile components of the reaction mixture are removed by distillation at 200 mbar and 100° C. The crude distillate contains 56% of 3-chloro-3-trimethylsiloxyhexamethyltrisiloxane, 29% of 3,3-dichlorohexamethyltrisiloxane and 16% of 3,3-bis(trimethylsiloxy)hexamethyltrisiloxane. The crude distillate is fractionally distilled, and gives, at 20 mbar and 83° to 87° C., 313 g (27% of theory) of 3-chloro-3-trimethylsiloxyhexamethyltrisiloxane in a purity, determined by gas chromatography, of 97%.

Workup

  1. customfitted with internal thermometer, stirrer and a reflux condenser
  2. customis kept at 45° C.
  3. temperatureby cooling
  4. customthe volatile components of the reaction mixture are removed by distillation at 200 mbar and 100° C
  5. distillationThe crude distillate is fractionally distilled

Sources & evidence

ORD record
ord-7293327dd8214fd993557a2f2786ba99
Source dataset
uspto-grants-1991_04
Patent number
US05011962

Reaction notes

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