IL45952A - Preparation of salts of o,o-dialkyl phosphorothioic acid esters - Google Patents

Description

Salts of phosphorotliioic acid esters chemical intermediates which can be used in the preparation of organopho sphorous The present invention pertains to a process for the preparation of calcium and salts of phosphorotliioic acid esterso Two general processes have been reported which describe the preparation of the calcium salts of phosphorotliioic acid esters In one Pessin and Eabachnik and an aqueous solution of a salt calcium was reacted with the ammonium or sodium salt of 0 phosphorotliioic acid ester to affect a exchange between the Another process patent publication 305 159 issued in the name of abriken BayerJ describes the preparation of calcium 0 phosphorothioate by reacting calcium oxide in aqueous medium with 0 phosphorotliioic acid These suffer from the sadvantage of having to use expensive and not always readily available such as the alkali salts of phosphorotliioic acid esters phosphorotliioic acid chloride In the preparation of salts of acid esters has been known since The early work was reviewed by ss who also reported a new process by reacting phosphite with sulfur and alkali A sirailar process was reported in German patent publication using and amines instead of alcoholateso Swiss patent number discloses salts of phosphorothiqic acid esters prepared by processeso have discovered a novel process for and barium salts of yl phosphoroihioic acid esters reacting a of phosphite in an alcohol solvent vith a mole of sulfur and a sufficient excess of calcium or barium oxide so as to form the phosphorothioic acid salt and react vith all the water formed the this novel process maintains the reaction under anhydrous preventing hydrolysis of the The excess calcium or barium oxide reacts vith the water to form the metal The novel process may be represented by the following 0 represents an calcium oxide is the insoluble calcium hydroxide is simply filtered barium oxide is any excess barium may be removed as the carbonate by bubbling carbon dioxide into the reaction This is ed when the barium hydroxide is appreciably soluble in alcoholic This process is particulr useful for the preparation of calcium or salts of phosphorothioic acid vhero the phosphite is easily Examples of 0 phosphites within the scope of the invention are 0 dibu and The calcium oxide used in the present invention be ordinary or technical preferably in the pothered and the solvent is a lover it is desired to avoid transesterification of the phosphite with the it is advisable to use the alcohol corresponding to the group of the phosphite We have found that calcium can be used successfully for the preparation of pesticides such as The following to be construed in a I To a boiling suspension cf 112 g calcium oxide and 64 sulfur in 5C0 methanol is slowly a solution of 220 g phosphite dissolved in 500 ml The mixture was then stirred for an additional hour and After removal of the solvent one obtains 300 g of white crystalline calcium Example 2 To a solution of phosphite and 64 g sulfur in 1 liter methanol is slowly at 307 g barium The mixture was then stirred for an additional The excess barium was precipitated by bubbling carbon dioxide into the solution and filtering off the barium carbonate After removal the solvent one obtains 371 g of barium Example Following the same procedure as in example but substituting there was prepared calcium insufficientOCRQuality

Claims (8)

WHAT IS CLAIMED IS;

1. A process for the production of calcium or barium salts of o,o-dialkl phosphorothioic acid esters, which comprises reacting equiraolar quantities ©f an ο,ο-dialkyl phosphite and sulfur in an alcoholic solvent in the presence of an excess of calcium oxide or barium oxide so as to form the desired calcium or barium salt 6nd also to bind all the water formed during the reaction,

2. A process in accordance with Claim 1, wherein the reactants are calcium oxide, sulfur, and ο,ο-dlmethyl phosphate.

3. A process in accordance with Claim 1, wherein the reactants are barium oxide, sulfur, and ο,ο-dimethl phosphite,

4. A process in accordance with Claim 1, wherein the reactants are calcium ©xide, sulfur, and o,©-diethyl phosphite.

5. A process as claimed in any of Claims 1*3* wherein the solvent is methanol.

6. · A process as claimed in any of Claims 1 ©r 4, wherein the solvent is ethanol.

7. A process/for ¾§e^oduc&on ©f aalclum and barium salts of ©,o~dialkyl phosphorothioic acid esters, substantially as hereinbefore described and with reference to the examples.

8. Calcium and barium salts of ο,ο-dialkyl phosphorothioic acid esters whenever obtained by a process as claimed in any of the preceding claims. A orney or pp cant