IMPROVED FORMULATIONS FOR OXIDATION, BLEACHING AND MICROBIAL CONTROL
Peracid salt compositions are prepared from acyl donor, hydrogen peroxide and alkali metal hydroxide under controlled conditions to provide nonequilibrium compositions at high product yield from input feedstocks. The prepared nonequilibrium compositions are surprisingly stable for beneficial employment to generate reactive oxygen species, and particularly singlet oxygen, during oxidation treatments.
1 . A method for preparing a nonequilibrium peracid salt composition to use to generate singlet oxygen during oxidative treatments, the method comprising:
reacting components in an aqueous reaction mixture prepared from a combination of chemical feedstocks to form an aqueous nonequilibrium peracid salt composition, the chemical feedstocks comprising acyl donor with acyl donor groups, hydrogen peroxide and alkali metal hydroxide in amounts and proportions, including to account for yield losses, to prepare the nonequilibrium peracid salt composition with composition properties comprising:
dissolved peracid anion of the peracid salt at a concentration in a range of from 1.0% (weight/volume) to 8.0% (weight/volume); and
pH in a range of from pH 12.0 to pH 13.5; and
wherein the combination of reaction feedstocks comprises:
a first molar ratio of the alkali metal hydroxide to the acyl donor groups in a range of from 1.00 to 1.40; and
a second molar ratio of hydrogen peroxide to the acyl donor groups in a range of from 0.80 to 1.00; and
continuing the reacting at least until the nonequilibrium peracid salt composition is prepared including the composition properties.
2 . The method of claim 1 , wherein the first molar ratio is in a range of from 1.05 to 1.30.
3 . The method of claim 2 , wherein the pH is in a range of from 12.5 to 13.2.
4 . The method of claim 3 , wherein the composition properties comprise a concentration of dissolved hydrogen peroxide of no larger than 1400 mg/L.
5 . The method of claim 1 , wherein the composition properties comprise a molar ratio of dissolved hydrogen peroxide to the peracid anion of no larger than 1/10.
6 . The method of claim 1 , wherein the composition properties comprise a 10-minute stability index (SI 10 ) at a temperature of 22° C. of at least 0.80, wherein the 10-minute stability index is calculated according to Equation I:
S
I
1
0
=
C
A
1
0
/
CA
0
Equation
I
wherein:
SI 10 is the 10-minute stability index;
CA 0 is the concentration (% weight/volume) of the peracid anion determined for a first time; and
CA 10 is a concentration (% weight/volume) of the peracid anion determined for a second time corresponding to 10 minutes following the first time.
7 . (canceled)
8 . The method of claim 6 , wherein the composition properties comprise a 30-minute stability index (SI 30 ) at a temperature of 22° C. of at least 0.65, wherein the 30-minute stability index is calculated according to Equation II:
SI
3
0
=
C
A
3
0
/
CA
0
Equation
II
wherein:
SI 30 is the 30-minute stability index; and
CA 0 is the concentration (% weight/volume) of the peracid anion determined for a first time; and
CA 30 is a concentration (% weight/volume) of the peracid anion determined for a third time corresponding to 30 minutes following the first time;
and wherein the 30-minute stability index is smaller than the 10-minute stability index by at least 0.05.
9 - 12 . (canceled)
13 . The method of claim 3 , wherein the composition properties comprise a weight ratio of total organic carbon to the peracid anion of no larger than 0.58.
14 - 16 . (canceled)
17 . The method of claim 3 , wherein the acyl donor is an acetyl donor; the nonequilibrium peracid salt composition is a nonequilibrium peracetic acid salt composition, and the peracid anion is peracetate.
18 . The method of any one of claim 3 , wherein the composition properties comprise the peracid anion at a concentration of at least 2.0% (weight/volume).
19 . The method of any one of claim 1 , wherein:
the first molar ratio is in a range of from 1.05 to 1.30;
the second molar ratio is in a range of from 0.87 to 1.00;
the composition properties comprise;
the peracid anion at a concentration in a range of from 3.0% (weight/volume) to 6.5% (weight/volume);
a concentration of hydrogen peroxide of no larger than 1200 mg/L; and
a pH of at least 12.4.
20 - 22 . (canceled)
23 . The method of claim 1 , wherein the combination of reaction feedstocks comprises a third molar ratio of the alkali metal hydroxide to hydrogen peroxide in a range of from 1.00 to 1.63.
24 . A nonequilibrium peracid salt composition made by the process of claim 17 .
25 . A method of oxidative treatment of a substrate, comprising:
preparing by the method of claim 1 a nonequilibrium peracid salt composition; and
contacting a substrate with the nonequilibrium peracid salt composition.
26 . The method of claim 25 , wherein the substrate comprises an aqueous liquid at a pH at least two pH units smaller than the pH of the nonequilibrium peracid salt composition immediately prior to the contacting.
27 . The method of claim 26 , wherein the substrate comprises a slurry comprising the aqueous liquid and pulp to be oxidatively treated to delignify and/or bleach the pulp.
28 . A method of oxidative treatment of a substrate, comprising:
preparing by the method of claim 1 a nonequilibrium peracid salt composition;
diluting the nonequilibrium peracid salt composition to prepare a diluted nonequilibrium peracid salt composition; and
contacting a substrate with a diluted nonequilibrium peracid salt composition.
29 . The method of claim 28 , wherein the substrate comprises a surface of a solid object to be sanitized.
30 - 31 . (canceled)
32 . An aqueous, nonequilibrium peracid salt composition for generation of singlet oxygen for use in oxidative treatments, the composition comprising:
dissolved peracid anion of an alkali metal salt of a peracid at a concentration in a range of from 1.0% (weight/volume) to 8.0% (weight/volume);
pH in a range of from pH 12.0 to pH 13.5;
a concentration of dissolved hydrogen peroxide of no more than 1400 mg/L;
a 10-minute stability index (SI 10 ) at a temperature of 22° C. of at least 0.80, wherein the 10-minute stability index is calculated according to Equation I:
S
I
1
0
=
C
A
1
0
/
CA
0
Equation
I
wherein:
SI 10 is the 10-minute stability index;
CA 0 is the concentration (% weight/volume) of the peracid anion determined for a first time; and
CA 10 is a concentration (% weight/volume) of the peracid anion determined for a second time corresponding to 10 minutes following the first time.
33 - 36 . (canceled)
37 . The composition of claim 32 , comprising a 30-minute stability index (SI 30 ) at a temperature of 22° C. of at least 0.65, wherein the 30-minute stability index is calculated according to Equation II:
SI
3
0
=
C
A
3
0
/
CA
0
Equation
II
wherein:
SI 30 is the 30-minute stability index; and
CA 0 is the concentration (% weight/volume) of the peracid anion determined for a first time; and
CA 30 is a concentration (% weight/volume) of the peracid anion determined for a third time corresponding to 30 minutes following the first time;
and wherein the 30-minute stability index is smaller than the 10-minute stability index by at least 0.05.
38 - 43 . (canceled)