An emulsion of the water-in-oil type containing as emulsifier a product made by heating in the presence of an etherification catalyst and/or a dehydrohalogenating agent and in the absence of a solvent (a) a polyepoxide, polyhalohydrin or epihalohydrin having a molecular weight not exceeding 400, and (b) an aliphatic or alicyclic monohydric alcohol containing at least 8 carbon atoms.  In the Examples:-(1) an emulsifier made by reacting epichlorohydrin with daidyl alcohol is dissolved in gas oil and petroleum sulphonate, barium sulphate being suspended in the resultant solution and an aqueous alkaline clay suspension emulsified therein; (2) the emulsifier of Example (1) is dissolved in lubricating oil and an aqueous solution of lithium hydroxide emulsified therein; (3) an emulsifier made by reacting an epoxy resin with oleyl alcohol is dissolved in white spirit, a vat dye being suspended in the resultant solution and an aqueous solution of sodium and potassium sulphoxylate emulsified therein.ALSO:A process for the preparation of an emulsifier comprises heating in the presence of an etherification catalyst and/or a dehydrohalogenating agent and in the absence of a solvent (a) a polyepoxide, polyhalohydrin or epihalohydrin having a molecular weight not exceeding 400, and (b) an aliphatic or alicylic monohydric alcohol containing at least 8 carbon atoms, said etherification catalyst and/or dehydrohalogenating agent being capable of effecting a condensation of (a) and (b) with a simultaneous polymerization of (a) and continuing the reaction until the reaction mass has the tendency to form threads and is soluble or dispersible in oil.  Specified components (a) are butadiene dioxide, diglycidyl ether, vinyl cyclohexane dioxide, 1:2-glycerol dichlorhydrin, 1:3-glycerol dichlorhydrin, epichlorhydrin, epibromhydrin, epiiodohydrin, a -methyl epichlorhydrin, b -methyl epichlorhydrin and a ,a 1-dimethyl epichlorhydrin and reaction products of polyepoxides, polyhalohydrins or epihalohydrins with compounds containing at least 2 reactive hydrogen atoms per molecule, e.g. polyhydric alcohols and phenols, amino compounds, malonic acid esters and phenol-aldehyde condensates of which many are specified. Specified etherification catalysts and dehydrohalogenating agents are aluminium chloride/boron trifluoride, zinc borofluoride, zinc chloride, ferric chloride, stannic chloride, phosphoric acid, sulphuric acid, p-toluene sulphonic acid and sodium chloride. Specified monohydric alcohols are fatty alcohols, and the alcohols obtained by the reduction of resinous or naphthenic acids.  In the Examples:-(1) elaidyl alcohol is reacted with epichlorhydrin in the presence of sulphuric acid, caustic soda is added and the mixture finally neutralized with acetic acid; (3) an epoxy resin made from epichlorhydrin and diphenylol propane is reacted with oleyl alcohol in the presence of sulphuric acid.  The product of Example (1) being mixed with :- (1) gas oil and petroleum sulphonate, barium sulphonate being suspended in the resultant solution and an alkaline clay dispersion emulsified therein; (2) lubricating oil, aqueous lithium hydroxide being emulsified in the resultant solution whilst the product of Example (3) is dispersed in paraffin oil or dissolved in white spirit to form a solution in which a vat dye is dispersed, sodium and potassium sulphoxylate and water being added to form an emulsion.