0100,0100,0100Dear colleagues : I kindly suggest to establish The Orglist Synthetic Letters, where simple and facile preparations of the important organic or inorganic compounds would be presented. The following synthesis is the first contribution into the forum. This is the original translation from the czech hanbook published in 1972. The full citation is mentioned below. Your comments are cordially welcomed. Preparation of formamidinesulfinic acid 116 g of 30 % hydrogen peroxide weight out in a beaker on accurate technical balance. Pour the hydrogen peroxide into a 1000 ml beaker and dilute it with 600 ml of distilled water. Place the beaker into a large vessel (e.g. enameled pot) and encase it with a mixture of gently grinded ice and sodium chloride. Place the glass stirrer powered with electric motor into the liquid and under continuing mixing allow the solution to cool down to 5 °C. Then, during two hours, under the continuing intensive mixing, add with spoon small doses of 38 g gently pulverized thiourea. The temperature during this process should be between 5 and 20 °C. Refresh the coolant if necessary. When all amount of thiourea is added continue with cooling of the mixture with ice and sodium chloride for next 1 hour. Then cool down all mixture close to freezing point. Filter the separated formamidinesulfinic acid preferably with small glass frit. Wash obtained product with small quantity of icy water and then with small portion of methanol. Washed acid is dried up in vacuum desiccator upon anhydrous calcium chloride. Characteristics: Formamidinesulfinic acid forms the colorless fine needles with melting point 144 °C. Formamidinesulfinic acid is slightly soluble in water. Saturated solution contains about 3 % of the acid and pH is about 5. It is soluble in acetic acid without decomposition. For its reducing properties the acid is useful in industry. Its ammoniacal solution rapidly absorbs the oxygen. Reference: Klikorka J., Klazar J., Votinsky J., Horak J.: Introduction into Preparative Inorganic Chemistry, SNTL Publishers, Prague 1972, page 188 (in Czech).0100,0100,0100 Next: Chemical properties of thiourea-dioxide. With love, J.Janovsky Institute of Chemical Technology Department of Physical Chemistry 5 Technical Street Prague, CZ 16628 Czech Republic __________________ ORGLIST - Organic Chemistry Mailing List Website / Archive / FAQ: http://www.orglist.net/ List coordinator: Joao Aires de Sousa (jas@mail.fct.unl.pt)