Reaction #5153

Reaction equation

1,2-Propanediol

trimethylsilyl chloride

→

colorless oil

(CH3)3SiOCH(CH3)CH2OSi(CH3)3

Solvents

HMDS

HMDS

HMDS

Conditions

Workup

1. 1
   Otheran exothermic reaction
2. 2
   Temperaturemaintaining the reaction temperature at ca. 50°-70° C
3. 3
   TemperatureHeating
4. 4
   Otherwas continued at 100° C.
5. 5
   Other(1.5 h), 120° C. (1.0 h),and 140° C. (2.5 h)
6. 6
   workup.DISTILLATIONDistillation

Procedure

1,2-Propanediol (58.8 g, 0.77 mol) was placed in a 500 mL 3-necked RB flask and treated with 0.2 mL trimethylsilyl chloride. A small volume of HMDS (ca. 10 mL) was added, and an exothermic reaction took place as the mixture became homogeneous. The remainder of the HMDS (170 mL) was added at a controlled rate (ca. 3-5 mL/min), maintaining the reaction temperature at ca. 50°-70° C. Heating was continued at 100° C. (1.5 h), 120° C. (1.0 h),and 140° C. (2.5 h). GC analysis (method 1) revealed excess HMDS and one product. Distillation provided 147 g of colorless oil, bp 70°-72° C./10 mm. 1H NMR (CDCl3): 3.83 (m, 1H), 3.50 and 3.38 (AB pattern with additional coupling, 2H), 1.15 (d, J=7 Hz, 3H), 0.15 (partially resolved singlets, 18H).

Source