Patent GB-999793-A (GB)
Title: Organic phosphate production
IPC: C08G18/38
Filed: 1961-06-19
Abstract: Organic phosphates are obtained by subjecting organic phosphites to reaction with peracetic acid.  The peracetic acid is preferably used in solution in an inert solvent, e.g. a fatty acid such as glacial acetic acid, an ester, e.g. methyl acetate, an acetal, e.g. methylal or a hydrocarbon, e.g. cyclohexane. Phosphates obtainable by the process are trialkyl, tricycloalkyl, trialkenyl, triaryl, triaralkyl, and trihaloalkyl phosphates, triheterocyclic phosphates, e.g. tris(tetrahydrofurfuryl) phosphate and phosphates containing mixed aliphatic and aromatic radicals, e.g. trisphenoxyethyl phosphate. Other phosphates obtainable are (a) bridged ring phosphates of the type:- <FORM:0999793/C2/1> wherein the free bond may be attached to an alkyl radical, e.g. ethyl, methyl or butyl, a hydroxymethyl radical, an aryl or aralkyl radical, e.g. phenyl or benzyl, a hydrogen atom, an amino group or a nitro group, and phosphates containing a plurality of bridged ring groups, e.g. those obtained from phosphites derived from dipentaerythritol; (b) phosphates containing epoxy groups which may be obtained by treating with peracetic acid organic phosphites in which at least one of the esterifying radicals has olefinic unsaturation, said phosphites being obtainable by transesterifying a phosphite and an olefinic hydroxy compound. The phosphites are oxidized to the phosphates together with epoxidation of their olefinic bonds.  Examples of such phosphates are trioleyl phosphate triepoxide, phenyl dioleyl phosphate diepoxide, oleyl diphenyl phosphate epoxide and tris-(epoxy monocrotylidene trimethylolpropane) phosphate; (c) cross-linked phosphates of the type:- <FORM:0999793/C2/2> wherein X is a polymethylene radical or a polyalkylene ether radical of the formula -R-(OR)n wherein R is an alkylene group and n is a number having a value of at least 1 and in which the terminal OH groups may be etherified with, e.g., butanol or esterified, e.g. with acetic anhydride and (d) phosphates containing at least one acetal ring, e.g. those having a structure of the type:- <FORM:0999793/C2/3> wherein R2 and R3 are selected from hydrogen, alkyl, hydroxy and hydroxyalkyl radicals, n is a number which is zero or more and x is a number of at least one.  The phosphites corresponding to the phosphates of the above formulae may be obtained by transesterification reaction between an organic phosphite, especially an aryl phosphite, with respectively: (a) a polyhydric alcohol having at least 3 methylol groups attached to a single carbon atom, (b) with an alkanediol or polyglycol, and (c) with an appropriate acetal ring-containing alcohol, which may be obtained by reacting an alcohol containing at least 3 hydroxy groups with a saturated or unsaturated aldehyde or ketone, e.g. crotonaldehyde, acetone or formaldehyde. Specified acetal ring-containing alcohols include monocrotylidene trimethylolpropane which is obtained by reacting trimethylolpropane with crotonaldehyde in the presence of an acid catalyst (e.g. phosphoric acid) at elevated temperature. Specification 889,338 is referred to.ALSO:Polymeric cross-linked phosphate esters which contain hydroxyl groups as chain terminators are obtained by oxidizing the corresponding polymeric phosphite esters with peracetic acid, the polymeric phosphites being obtained by transesterifying a phosphite such as an aryl phosphite, e.g. triphenyl, tricresyl or trixylenyl phosphite, with a glycol or polyglycol, preferably in a proportion of 1.5 to 3 mols of the glycol per mol of the phosphite triester.  Specified glycols are pentamethylene glycol, diethylene glycol, dipropylene glycol and other polypropylene glycols, e.g. polypropylene glycol of molecular weight 1025, dihydroxymethyl benzene and aromatic glycol ethers, e.g. dioxyethylol benzene.  The transesterification may be catalysed by sodium metal.  The oxidation with peracetic acid is preferably carried out in an inert solvent, e.g. glacial acetic acid, methyl acetate, methylal or cyclohexane.  If desired the terminal OH groups in the phosphate products may be etherified, e.g. with butanol, or esterified, e.g. with acetic anhydride.  The polyphosphite and polyphosphate esters may be reacted with diisocyanates to form polyurethanes.  Epoxidized alkenyl phosphates obtained by reacting the corresponding alkenyl phosphites with peracetic acid (see Division C2) are useful as plasticizers for polyvinyl chloride. Typical epoxy-phosphates are trioleyl phosphate triepoxide, phenyl dioleyl phosphate diepoxide, oleyl diphenyl phosphate epoxide and tris-(epoxy monocrotylidene trimethylol-propane) phosphate. Specification 889,338 is referred to.