Propylene Glycol → 2,2,4,7,7-Pentamethyl-3,6-dioxa-2,7-disilaoctane

Participants

Reaction Conditions

Reaction Steps

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, 1 H), 3.50 and 3.38 (AB pattern with additional coupling, 2 H), 1.15 (d, J=7 Hz, 3 H), 0.15 (partially resolved singlets, 18 H).

Provenance & Evidence