Tetraethoxymethane is a chemical compound which is formally formed by complete ethylation of the hypothetical orthocarbonic acid C(OH)4 (orthocarbonic acid violates the Erlenmeyer rule and is unstable in the free state).
History Tetraethoxymethane was described the first time in 1864.H. Bassett, Ueber das vierfach-basische kohlensaure Aethyl, Ann. 132, 54 (1864), .
Synthesis The preparation of tetraethoxymethane from the highly toxic trichloronitromethane is known in the literatureH. Tieckelmann, H.W. Post, The preparation of methyl, ethyl, propyl, and butyl orthocarbonates, J. Org. Chem., 13 (2), 265–267 (1948), .Europäische Patentschrift EP 0881212 B1, Production method of aminobenzene compound, Erfinder: H. Hashimoto et al., Anmelder: Takeda Chemical Industries, Ltd., veröffentlicht am 30. Oktober 2001. and achieves only yields of 46-49 to 58%:
The obvious synthetic route from tetrachloromethane does not provide the desired product, as in the homologous tetramethoxymethane.
Starting from the less toxic trichloroacetonitrile (compared with trichloronitromethane), higher yields can be obtained (up to 85%).US-Patent US 6825385, Process for the preparation of orthocarbonates, Erfinder: G. Fries, J. Kirchhoff, Anmelder: Degussa AG, erteilt am 30. November 2004. An alternative reaction, bypassing problematic reactants, is the reaction of dialkyltin dialkoxides with carbon disulfide at elevated temperature in an autoclave:S. Sakai et al., Reaction of Dialkyltin Dialkoxides with Carbon Disulfide at Higher Temperature. Preparation of Orthocarbonates, J. Org. Chem., 36 (9), 1176 (1971), .
Another route reacts thallous ethoxide with carbon disulfide in dry methylene dichloride.Shizuyoshi Sakai, Yoshitaka Kuroda, Yoshio Ishii (1972): "Preparation of orthocarbonates from thallous alkoxides and carbon disulfide". Journal of Organic Chemistry, volume 37, issue 25, pages 4198–4200.
A more recent synthesis starts directly from sodium ethoxide, tin(IV)chloride, and carbon disulfide.S. Sakai et al., A new method for preparation of tetraalkyl orthocarbonates from sodium alkoxides, tetrachlorostannane, and carbon disulfide, Synthesis 1984 (3), 233–234, .
Properties Tetraethoxymethane is a water-clear, aromatic or fruity smelling,J. H. Ruth, Odor Thresholds and Irritation Levels of Several Chemical Substances: A Review, Am. Ind. Hyg. Assoc. J. 47, A-142 – A-151, (1986). liquid of low-viscosity which is unstable against strong acids and strong bases.
Uses Tetraethoxymethane can be used as a solvent and for the alkylation of CH-acidic compounds (e.g. phenols and carboxylic acids). In addition, it reacts with amines, enol ethers and sulfonamides,W. Kantlehner et al., Die präparative Chemie der O- und N-funktionellen Orthokohlensäure-Derivate, Synthesis, 1977, 73–90. whereby spiro compounds can also be obtained. Spiro orthocarbonates (SOCs) are of some industrial interest, as they are used as additives for reducing shrinkage during the polymerization of epoxides (they are used as expanding monomers).R. Acosta Ortiz et al., Novel diol spiro orthocarbonates derived from glycerol as anti-shrinkage additives for the cationic photopolymerization of epoxy monomers, Polymer International, 59(5), 680–685 (2010), .
References