GB813460A - New esters of hyponitrous acid and their preparation - Google Patents

Abstract

The invention comprises polymeric esters of hyponitrous acid wherein the organic residues contain at least one ether oxygen atom, preferably on the alpha carbon. The polymeric esters preferably contain units of the general structure -X-OCHY-ON=NO- wherein X1 may be alkenyl, alkoxyalkenyl, cycloalkenyl or arylene and Y may be hydrogen, alkyl, cycloalkyl, aryl, alkoxy, or alkoxyaryl or may form part of a ring with X1. The novel hyponitrites may be prepared by interaction between silver hyponitrite or other metal hyponitrite and a dihalide Hal-R-Hal, where R is an organic radical containing at least one ether oxygen, preferably in solution in an inert hydrocarbon solvent, for example white spirit, ethers or aromatic hydrocarbons. The reaction is controlled by external cooling of the reaction mixture usually to a temperature of - 20 DEG to 10 DEG C., preferably below - 10 DEG C. When the reaction is finished, the metal halide may be removed by filtration. The so-obtained solution of hyponitrite may be used as such in the polymerization of ethylenically unsaturated compounds, or the hyponitrite may be isolated therefrom, e.g. by evaporation of the solvent. In Example (13), silver hyponitrite and the diethyl ether of ethylene glycol are mixed at - 20 DEG C. and sym-dichloro-dimethyl ether is added slowly, the mixture being stirred at - 20 for 12 hours after which the chloride is removed by filtration. The product is poly1:2-aza : 3:5:7-oxaheptane. Polymerization of ethylenically unsaturated compounds.-Esters of hyponitrous acid (both monomeric and polymeric) wherein the organic residues contain at least one ether oxygen atom are valuable catalysts for the polymerization of ethylenically unsaturated compounds such as ethylene and vinyl acetate. The solution of hyponitrite obtained by interaction of a metal hyponitrite with a monohalide R-Hal (see Group IV (b)) or a dilahide Hal-R-Hal, where R is an organic radical containing at least one ether oxygen atom, in an inert solvent, may be used as such. The hyponitrite may be prepared in solution in the liquid monomer which is to be polymerized. In Example 34, silver hyponitrite is reacted with methyl chloromethyl ether in liquid ethylene to give bis-methoxy methyl hyponitrite; the fluid contents of the reaction vessel are discharged to a storage vessel, a flush of liquid ethylene is passed through the reaction vessel to the storage vessel, more ethylene is added and compressed to 1500 atm. and on allowing the contents of the storage vessel to warm to room temperature, polymerization of the ethylene ensues. Bis - (a ,a - di - ethoxyethyl) hyponitrite and bis-triethoxymethyl hyponitrite in ether (Examples 33 and 27) are also specified as catalysts for the polymerization of ethylene. Specification 618,168 is referred to.ALSO:The invention comprises esters of hyponitrous acid RO-N=N-OR1 wherein the organic radicals R and R1 contain at least one ether oxygen, preferably on the a -carbon atom. R and R1, and optionally the hyponitrous acid residue may form part of a ring system. The novel hyponitrites include esters of the formula (XOCHYON)2 wherein X may be alkyl, alkoxyalkyl, cycloalkyl or aryl and Y may be hydrogen, alkyl, cycloalkyl, aryl, alkoxy or alkoxyalkyl, or may form part of a ring with X; and polymeric esters containing units of the general structure -X1-OCHY-ON = N-O-wherein X1 may be alkenyl, alkoxyalkenyl, cycloalkenyl or arylene and Y is as defined above. The preferred compounds have the formula: R11-O-CH2-O-N = N-O-CH2-O-R11 wherein R11 represents ethyl, n or iso-propyl, n, iso or sec-butyl, iso-amyl, n or sec-octyl, 2 : 4 : 4 - trimethylpentan - 2 - yl, 3 : 5 : 5-trimethylhexan-1-yl, dodecyl or cyclohexyl, or stands for a difunctional group containing, for example, other or the same a -alkoxyalkyl hyponitrite groups, or a -chloroether groups. Also within the preferred class are tetrahydropyranyl and tetrahydrofuranyl hyponitrites. The new organic hyponitrites may be prepared by interaction between silver hyponitrite or other metal hyponitrite and a halide R-Hal, or Hal-R-Hal where R is as above defined, preferably in solution in an inert hydrocarbon solvent, for example white spirit, ethers or aromatic hydrocarbons. Other solvents include liquefied gases including ethylene and other polymerizable monomers. The reaction is controlled by external cooling of the reaction mixture usually to a temperature of -20 DEG C. to 10 DEG C., preferably below -10 DEG C. When the reaction is finished, the silver halide may be removed by filtration. The solution of hyponitrite obtained may be used as such, for example in the polymerization of ethylenically unsaturated compounds, or the hyponitrite may be isolated by evaporation of the solvent at low temperatures or by crystallization at low temperature. Examples describe the preparation of bis-methoxymethyl hyponitrite, bis - isobutoxymethyl hyponitrite, tetrahydropyran hyponitrite, bis - cyclohexyloxymethyl hyponitrite, tetrahydrofuran hyponitrite, bis-a - methoxybenzyl hyponitrite, bis - a - ethoxy-a - cyclohexylmethyl hyponitrite, bis - phenoxymethyl hyponitrite, poly - 1 : 2 - aza - 3 : 5 : 7 - oxaheptane, bis - chloromethoxymethyl hyponitrite, bis - (a - isobutoxyethyl) hyponitrite, bis - (a - methoxyisobutyl) hyponitrite, bis - (t - butoxymethyl) hyponitrite, bis - ethoxycarbethoxymethyl hyponitrite, bis-dodecyloxymethyl hyponitrite, bis - octan - 2 - oxymethyl hyponitrite, bis - isoamyloxymethyl hyponitrite, bis - (a ,a - diethoxyethyl) hyponitrite, bis - triethoxymethyl hyponitrite, bis - (1 : 3 - dimethylbutoxymethyl) hyponitrite, bis - (3 : 5 : 5 - trimethylhexyloxymethyl hyponitrite, bis - [(b - ethoxy) ethoxymethyl] hyponitrite. Metal hyponitrites used in the examples are those of silver, sodium barium, lead, copper, thallium, cobalt and manganese. Solvents used are white spirit, the diethyl ether of diethylene glycol, the diethyl ether of ethylene glycol, ethyl ether, petroleum ether, toluene, diethyl oxalate, liquid ethylene, and acetone, An example also describes the reaction of silver hyponitrite with ethylorthoformate in dry ether while passing in anhydrous hydrogen chloride. The Provisional Specification includes hyponitrites having the formul : <FORM:0813460/IV (b)/1> and <FORM:0813460/IV (b)/2>