Verfahren zur Herstellung eines Dispergiermittels

The invention comprises compounds of the general formula wherein A represents a trivalent polynuclear radical containing at least 2 fused aromatic rings optionally substituted by chlorine but unsubstituted by alkyl groups, X represents O(CH2CH2O)xCH2CH2OH, -COO(CH2CH2O)CH2\CH2OH, -S(CH2CH2O)xCH2\CH2OH, -NH(CH2CH2O)xCH2CH2OH, or-N[(CH2CH2O)xCH2CH2OH]2, x being an integer from 1 to 100 and preferably from 4 to 20, n is zero or a number greater than zero, R represents hydrogen or a monovalent hydrocarbon radical containing up to 6 carbon atoms. A is preferably a naphthalene nucleus but may be an anthracene or other polynuclear aromatic nucleus. The novel compounds may be made by reacting a substituted polynuclear aromatic compound bearing as a substituent a polyethenoxy chain represented by X with an aldehyde, preferably formaldehyde or paraform. Thus a naphthol or naphthalene compound containing a carboxyl group, a thiol group, or an amino group may be reacted with ethylene oxide and thereafter with an aldehyde such as formaldehyde. The condensation with the aldehyde is preferably effected in the presence of a strong mineral acid such as sulphuric acid, if desired in aqueous medium, and preferably at a temperature between 60 DEG C. and 150 DEG C.ALSO:The invention comprises compounds of the general formula wherein A represents a trivalent polynuclear radical containing at least 2 fused aromatic rings optionally substituted by chlorine but unsubstituted by alkyl groups, X represents O(CH2CH2O)xCH2CH2OH; -COO(CH2CH2O)xCH2CH2OH; -S(CH2CH2O)xCH2CH2OH; -NH(CH2CH2O)xCH2CH2OH; or -N[(CH2CH2O)xCH2CH2OH]2; x being an integer from 1 to 100 and preferably from 4 to 20, n is zero or a number greater than zero, R represents hydrogen or a monovalent hydrocarbon radical containing up to 6 carbon atoms. A is preferably a naphthalene nucleus but may be an anthracene or other polynuclear aromatic nucleus. The novel compounds may be made by reacting a substituted polynuclear aromatic compound bearing as a substituent a polyethenoxy chain represented by X with an aldehyde, preferably formaldehyde or paraform. Thus a naphthol or a naphthalene compound containing a carboxyl group, a thiol group, or an amino group may be reacted with ethylene oxide and thereafter with an aldehyde such as formaldehyde. The condensation with the aldehyde is preferably effected in the presence of a strong mineral acid such as sulphuric acid, if desired in aqueo