Acrylic Acid → Trichlorogermane propionic acid

An example of this alternative process follows. To a 50 L glass reactor was added successively: 7.2 Kg germanium tetrachloride, 5.3 Kg tetramethyl disiloxane, and 2.32 Kg of acrylic acid. The resulting mixture was stirred for 5 days forming TPA (trichlorogermane propionic acid) as a product. Volatile components were removed via vacuum distillation while the TPA product was heated to an internal temperature of 75° C.--80° C., where it was a homogeneous, clear and colorless viscous melt. Distillation is continued until no more distillate appears. The product was then cooled to ambient temperature yielding a white amorphous solid of TPA. To this was added 35 L of concentrated HCl. The resulting heterogeneous mixture was warmed to an internal temperature of 60° C.-70° C., and stirred for four hours and allowed to cool. The cooled mixture was extracted 3 times with 25 L of dichloromethane. The dichloromethane was removed with vacuum distillation at 40° C. to give a white amorphous solid. The white amorphous solid, crude TPA, was then hydrolyzed to carboxyethyl germanium sesquioxide. This was immediately taken up (vigorous reaction), with careful addition of 30 L of ammonium hydroxide (29% ammonia). The resulting mixture was stirred for 4 days at ambient temperature. To this, 14.4 L of concentrated sulfuric acid was added dropwise over two hours through a reflux condenser at a temperature not greater than 25° C. producing a white solid of carboxyethyl germanium sesquioxide. The white solid was isolated via suction filtration, washed successively with 2×5.4 L acetone, and 2×5.4 L of dimethyl ether, then the resulting brilliant white solid was air dried overnight, and then taken up with 9 L of hot water (~80° C.), and stirred for two hours, cooled and filtered to give a white solid which was washed twice in 5.4 L t-botyl methyl ether to yield carboxyethyl germanium sesquioxide.