Hydrogen sulphide and mercaptans scavenging compositions

A method for scavenging hydrogen sulphide and/or mercaptan in hydrocarbon streams, comprising contacting the hydrocarbon stream with a composition, wherein the weight ratio between hydrogen sulphide contained in the hydrocarbon stream before the step of contacting and the composition ranges from 1:0.9 to 1:0.2,

• the composition comprising an oxazolidine compound and an additive selected from partial polyol esters comprising x ester units, y hydroxylated units and z ether units, x, y and z being integers such that x varies from 1 to 10, y varies from 1 to 10, and z varies from 0 to 50, wherein the weight ratio of oxazolidine compound(s) to said additive(s) ranges from 1 to 50, wherein the composition comprises from 19 to 99% wt of oxazolidine compound(s) and from 1 to 50% wt of said additive(s), based on the total weight of the composition,
• wherein the oxazolidine compound has a structure of formula (I):
• wherein
• n is an integer ranging from 1 to 6;
• R1 and R2, identical or different, are selected from a hydrogen atom and a linear, branched or cyclic alkyl or alkenyl groups having from 1 to 6 carbon atoms, and wherein the polyols are chosen from the group comprising erythritol, xylitol, D-arabitol, L-arabitol, ribitol, sorbitol, malitol, isomalitol, lactitol, sorbitan, volemitol, mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol, 1,1,1-tri(hydroxymethyl) ethane, trimethylolpropane and carbohydrates.