Sulfur containing ashless disperant

An ashless dispersant comprises a polyalkyleneamine having one of its terminal primary amine groups condensed with a first acid which is an alkenylsuccinic anhydride, alkenyl-succinic acid or alkenylmonocarboxylic acid wherein the alkenyl groups contain 40 to 250 carbon atoms, and having its second terminal primary amine group condensed with the first acid or with a C1 to C30 carboxylic acid or with a C1 to C10 aldehyde or ketone containing only C, H and O atoms, said polyalkyleneamine containing 3 to 13 amine groups and the alkylene groups thereof each containing 2 or 3 carbon atoms, the ashless dispersant being sulphurized to a sulphur content of 0.1 to 5.0 weight per cent, based on the weight of the sulphurized dispersant. The sulphurization may be carried out by heating the dispersant, usually dissolved in mineral oil, at a temperature of 200 DEG to 400 DEG F. for 0.25 to 10 hours. In the examples the following dispersants are dissolved in a mineral lubricating oil and then sulphurized using (i) elemental sulphur optionally with P4S3 or with zinc oxide +zinc stearate or with zinc oxide+diethylenetriamine; (ii) S2Cl2; (iii) P2S5; (iv) CS2; or (v) P4S3:-Dispersant A is obtained by reacting 2 molar proportions of polyisobutenylsuccinic anhydride with 1 molar proportion of tetraethylenepentamine; Dispersant C is obtained by reacting equimolar proportions of polyisobutenylsuccinic anhydride, diethylenetriamine and benzaldehyde and Dispersant D is obtained by reacting 3 molar proportions of polyisobutenyl propionic acid with 1 molar proportion of tetraethylenepentamine. The polyisobutenyl propionic acid is obtained by reacting chlorinated polyisobutylene with acrylic acid. For comparison Dispersant B is prepared by reacting equimolar proportions of polyisobutenylsuccinic anhydride and tetraethylenepentamine and Dispersant E by reacting equimolar proportions of polyisobutenyl propionic acid and tetraethylenepentamine.ALSO:Ashless sulphurized dispersants for use in fluid petroleum hydrocarbons and lubricating oil concentrates comprise a polyalkyleneamine having one of its terminal primary amine groups condensed with a first acid which is an alkenylsuccinic anhydride, alkenylsuccinic acid or alkenylmonocarboxylic acid wherein the alkenyl groups contain 40 to 250 carbon atoms, and having its second terminal primary amine group condensed with the first acid or with a C1- 30 carboxylic acid or with a C1 to C10 aldehyde or ketone containing only C, H and O atoms, s