GB1061768A - Hydroxyalkylated alkenyl phosphonic acids and esters thereof and process for preparing them - Google Patents

Abstract

The invention comprises hydroxyalkyl esters of a ,b -unsaturated alkenyl phosphonic acids of formula <FORM:1061768/C2/1> wherein R1 and R2 are each hydrogen or C1 to C6 alkyl; R3 is H, Cl, Br, or C1 to C6 alkyl; R4 and R5 are each H, C1 to C6 alkyl, hydroxymethyl, chloromethyl, or phenyl which may be substituted by e.g. C1 to C4 alkyl, or Cl, at least one of R4 and R5 being H; and optionally R4 and R5 in some groups of formula <FORM:1061768/C2/2> being different from R4 and R5 in other such groups in the chain; n is a number from 1 to 40; and X is H, alkyl, alkenyl, cycloalkyl, or the group <FORM:1061768/C2/3> wherein R4, R5, and n are as above, and where the said group may be different from the corresponding group attached to the other oxygen atom. The compounds are prepared by reacting an a ,b -unsaturated alkenyl phosphonic acid, or an alkyl, cyclo-alkyl or alkenyl semi-ester thereof, or an alkali metal or ammonium salt of such an acid or ester, with a 1,2-alkylene oxide, or a haloalkyl or hydroxyalkyl substituted 1,2-alkylene oxide at a temperature of from 10 DEG to 180 DEG C. Suitable a ,b -unsaturated alkenyl phosphonic acids are vinyl- or propenyl-phosphonic acids and higher homologues having up to 8 C in the alkenyl group, and the corresponding halogenated acids. Semi-esters thereof may be those of saturated or unsaturated C1 to C21 aliphatic alcohols, e.g. methanol, ethanol, butanol, iso-butanol, 2-ethyl hexanol, dodecanol, octadecanol, and allyl or oleyl alcohol, or their salts such as the ammonium, potassium, lithium or sodium salts, or mixtures of free acids, semi-esters, and salts. Suitable alkylene oxides are ethylene oxide and derivatives thereof; propylene-; 1,2-butylene-; and 1,2-pentylene oxides; halo-alkyl-alkylene oxides and hydroxy-alkyl-alkylene oxides, e.g. epichlorohydrin, epibromohydrin, and hydroxymethyl ethylene oxide. Also styrene oxide and its derivatives-e.g. substituted in the phenyl group by C1 to C4 alkyl or chlorine-may be used. The reaction may be carried out by reacting the starting materials at 10-180 DEG C., preferably in the absence of air under an inert atmosphere, and, if necessary, in an inert or reacting solvent -e.g. benzene, toluene, xylene, chlorobenzene, ethyl acetate, acetone, acetophenone, diethyl ether, dioxan, methanol, ethanol, or water. If reacting solvents such as water, are used, they must react to only a minor degree with the alkylene oxide compared with the reaction of the latter with the phosphonic acid. For example, when reacting sodium vinyl phosphonate and ethylene oxide in water the reaction is: <FORM:1061768/C2/4> When low boiling point alkylene oxides are employed, the reaction may be conducted under superatmospheric pressure in a closed vessel. The reaction usually occurs in the absence of hydroxyalkylation catalysts, but these may be used, especially to prepare products having a high degree of hydroxyalkylation, e.g. having more than 4 hydroxy alkyl groups bound to each other. Such catalysts may be alkali metal or earth metal hydroxides, oxides, carbonates or bicarbonates; free alkali metals; Lewis acids such as boron fluoride and complexes thereof with ethers or alcohols. Also, to achieve such higher hydroxylation, the reaction may be performed in two stages, the first without a catalyst, and the product being further hydroxylated with the aid of a catalyst. Mixtures of alkylene oxides may be employed in the process; alternatively an unsaturated alkenyl phosphonic acid may be first reacted with an alkylene oxide more hydrophobic than ethylene oxide-e.g. propylene or 1,2-butylene oxide-and the resulting product then polyhydroxyethylated. The reaction is complete when no more alkylene oxide is taken up, but may be interrupted prematurely to yield a product of lower degree of hydroxylation. Examples are given for the preparation of the reaction products of the following reactants: (a) vinyl phosphonic acid and (i) ethylene oxide, under several different conditions; (ii) propylene oxide; (iii) propylene oxide followed by ethylene oxide; or (iv) epichlorohydrin; and (b) vinyl phosphonic acid-2-ethylhexyl ester and ethylene oxide.