Non-ionic surfactant compositions

An alcohol ethoxylate surfactant composition comprising alcohol ethoxylates of formula (II):

• HO.(EO)n3.R3 (II)
• in which:
• EO is an ethylene oxide residue (—CH2.CH2.O—);
• R3 is alkyl from two populations R3a and R3b, where:
• in population R3a, the alkyl groups have from 8 to 12 carbon atoms and an average number of carbon atoms from 9 up to less than 12;
• and
• in population R3b, the alkyl groups are having from 12 to 16 carbon atoms and an average number of carbon atoms from 12 to 15;
• n3 is from two populations n3a and n3b, corresponding to the populations R3a and R3b respectively, where n3a is from 3 to 8 and n3b is from 4.5 to 9;
• where the weight proportions of the two populations is such that the overall average number of carbon atoms (C) in the alkyl groups of R3 is from 10.5 to 12 and the overall average value of n3 is from 4.5 to 8;
• and
• wherein the weight ratio of the groups R3a and R3b, based on the respective alcohols, is in the range 50:50 to 85:15.

A surfactant composition comprising a mixed-alcohol ethoxylate of the formula (III):

• HO.(EO)n4.R4 (III)
• in which:
• EO is an ethylene oxide residue (—CH2.CH2.O—);
• n4 is from 4.5 to 8;
• and
• R4 represents alkyl residues of a mixed-alcohol such that:
• a first portion of the alkyl groups has from 8 to 12 carbon atoms and an average number of carbon atoms from 9 up to less than 12;
• and
• a second portion of the alkyl groups has from 12 to 16 carbon atoms and an average number of carbon atoms from 12 to 15;
• the respective alcohols being present in the mixed-alcohol in weight proportions such that the overall average number of carbon atoms (C) in the alkyl groups of R4 is from 10.5 to 12;
• and
• wherein the weight ratio of the first portion of alkyl groups and the second portion of alkyl groups, based on the respective alcohols, is in the range 50:50 to 85:15.

A method for reducing the aquatic toxicity of alcohol ethoxylate nonionic surfactants of the general formula HO.(EO)n.R, wherein EO represents ethylene oxide residues (—CH2CH2.O—) and R represents alkyl, which comprises:

• (I) forming a mixture of such first and second alcohol ethoxylate nonionic surfactants, wherein the first nonionic surfactant comprises from 3 to 8 EO residues and an alkyl chain length of from 8 to 12 carbon atoms and an average number of carbon atoms from 9 to less than 12;
• wherein the second nonionic surfactant comprises from 4.5 to 9 carbon atoms and an alkyl chain length from 12 to 16 and an average number of carbon atoms from 12 to 15;
• further wherein the weight proportions of the first and second surfactants provides an overall average number of carbon atoms in the alkyl groups from 10.5 to 12 and an overall average number of EO residues from 4.5 to 8;
• and still further wherein the weight ratios of the alkyl groups in the first nonionic surfactant to the alkyl groups in the second nonionic surfactant is in the range 50:50 to 85:15;
• or,
• (II) in said general formula selecting the alkyl groups represented by R to include a first population having from 8 to 12 carbon atoms and an average number of carbon atoms from 9 to less than 12 and a second population having from 12 to 16 carbon atoms and an average number of carbon atoms from 12 to 15;
• and providing the number of EO residues in the first population from 3 to 8, and the number of EO residues in the second population from 4.5 to 9;
• and providing the weight proportions of the first and second populations such that the overall number of carbon atoms in the alkyl groups is from 10.5 to 12 and the average overall number of EO residues is from 4.5 to 8, and wherein the weight ratio of the alkyl groups in the first population to the alkyl groups in the second population, is in the range from 50:50 to 85:15;
• or
• (III) in said general formula selecting the alkyl groups represented by R from a mixed alcohol having from 4.5 to 8 EO residues;
• wherein a first portion of the alkyl groups has from 8 to 12 carbon atoms and an average number of carbon atoms from 9 up to less than 12;
• and a second portion of the alkyl groups has from 12 to 16 carbon atoms and an average number of carbon atoms from 12 to 15;
• and providing the respective alcohols in the mixed-alcohol in weight proportions such that the overall average number of carbon atoms in the alkyl groups is from 10.5 to 12;
• wherein the weight ratio of the first portion of alkyl groups to the second portion of alkyl groups, based on the respective alcohols, is in the range 50:50 to 85:15.