| abstract |
A new class of oil-soluble, sulfur scavengers or converts are disclosed where the scavengers include substantially monomeric aldehyde-amine adducts from the reaction of at least one sterically hindered primary or secondary amine and a molar excess of at least one aldehyde or a donor thereof. Preferably the adduct is a compound of formulas (I), (II) or mixtures thereof: <CHE>CH2R - NR<1>R<2>```(I)</CHE> <CHE>CH2R - R<4>NR<3>NR<5> - CH2R```(II)</CHE> where R is a hydrogen atom (H) or a carbon-containing group, R<1> and R<2> are the same or different and may be H (for example), at least one being a sterically hindered carbon-containing group having between about 3 and about 24 carbon atoms or R<1> and R<2> can form a ring system, R<3> is a divalent sterically hindered carbon-containing group, R<4> and R<5> are the same or different and are H or a CH2R group and where one or more of the carbon atoms of R, R<1>, R<2>, R<3>, R<4>, R<5> or mixtures thereof can be replaced by oxygen atoms in the form of ether moieties, nitrogen groups in the form of tertiary amine or amide moieties or mixtures thereof, and where one or more hydrogen atoms of R, R<1>, R<2>, R<3>, R<4>, R<5> or mixtures thereof can be replaced by fluorine atoms, chlorine atoms or mixtures thereof. Methods are also disclosed for reducing, reducing below a given level or eliminating noxious sulfur species from fluids using these scavengers and for making them. A plot shows pressure and H2S concentration verses time for a scavenger embodying this invention compared with comparative Triazine 1, 2 and 3 scavengers tested at high pressure in a sour gas-drilling mud system pressure and headspace H2S composition profiles at about a 10:1 scavenger to H2S ratio. |