Peroxycarboxylic acid compositions suitable for inline optical or conductivity monitoring
Peracid stable fluorescent active compounds in highly acidic, equilibrium peroxycarboxylic acid sanitizing compositions are disclosed as having improved fluorescent stability allowing for monitoring of peroxycarboxylic acid concentration by conductivity and/or optical sensors. Beneficially, the compositions are also low odor and low/no VOC dual functioning acid wash and sanitizing compositions.
1. A method for detecting a concentration of peroxycarboxylic acid and/or hydrogen peroxide in a sanitizing composition and/or cleaning process comprising:
providing an equilibrium peroxycarboxylic acid composition comprising a C 1 -C 22 peroxycarboxylic acid, a C 1 -C 22 carboxylic acid, hydrogen peroxide, and an alkyl aryl sulfonate fluorescent active compound, wherein the fluorescent active compound is stable in the equilibrium peracid composition;
measuring a fluorescence response of said equilibrium peroxycarboxylic acid composition with an optical cell, wherein the fluorescence response measures the intensity of fluorescent emission of said fluorescent active compound; and
determining a concentration of the peroxycarboxylic acid and/or the hydrogen peroxide of said equilibrium peroxycarboxylic acid composition based on the correlation of said fluorescent emission of said fluorescent active compound and the concentration of the peroxycarboxylic acid and/or the hydrogen peroxide.
2. The method of claim 1 , further comprising diluting the equilibrium peroxycarboxylic acid composition into a use solution.
3. The method of claim 2 , wherein the use solution of the equilibrium peroxycarboxylic acid composition is directed to an optical cell.
4. The method of claim 2 , wherein the use solution of the equilibrium peroxycarboxylic acid composition is measured for a fluorescence response from the fluorescent active compound.
5. The method of claim 4 , wherein the fluorescence response is a fluorescent signal detected by an optical cell during a circulating, soaking, cleaning and/or rinsing step.
6. The method of claim 1 , further comprising placing an optical cell in or along a feed line delivering the peroxycarboxylic acid compositions to a cleaning application.
7. The method of claim 1 , further comprising adjusting the concentration of the peroxycarboxylic acid and/or the hydrogen peroxide of the composition based on the measured fluorescence response.
8. The method of claim 1 , further comprising removal of at least a portion of the peroxycarboxylic acid composition to provide a new equilibrium peroxycarboxylic acid composition for dilution and use in a cleaning and/or sanitizing application.
9. The method of claim 1 , wherein the cleaning process is performed on-line or is conducted off-line using a clean-in-place system.
10. The method of claim 1 , wherein the C1-C22 peroxycarboxylic acid is a C2-C20 peroxycarboxylic acid selected from the group consisting of peroxyacetic acid, peroxyoctanoic acid, peroxysulfonated oleic acid and combinations thereof, wherein the C1-C22 carboxylic acid is a C2-C20 carboxylic acid selected from the group consisting of acetic acid, octanoic acid, sulfonated oleic acid and combinations thereof, and wherein the fluorescent active compound is sodium xylene sulfonate, toluene sulfonate, alkyl benzenesulfonate, alkyl diphenyl oxide disulfonate, naphthalene sulfonate, alkyl naphthalene sulfonate, naphthalene disulfonate or sodium cumene sulfonate.
11. The method of claim 1 , wherein the C 1 -C 22 peroxycarboxylic acid comprises from about 1 wt-% to about 40 wt-%, the C 1 -C 22 carboxylic acid comprises from about 1 wt-% to about 80 wt-%, the hydrogen peroxide comprises from about 1 wt-% to about 80 wt-%, and the fluorescent active compound comprises from about 0.001 wt-% to about 10 wt-%, and wherein the equilibrium peroxycarboxylic acid composition further comprises at least one additional agent selected from the group consisting of a hydrotrope, a solvent, a stabilizing agent, an anionic surfactant, a metal salt defoaming agent, and combinations thereof.
12. The method of claim 1 , wherein the fluorescent active compound is sodium xylene sulfonate, toluene sulfonate, alkyl benzenesulfonate, alkyl diphenyl oxide disulfonate, naphthalene sulfonate, alkyl naphthalene sulfonate, naphthalene disulfonate or sodium cumene sulfonate, and wherein the equilibrium peroxycarboxylic acid composition further comprises an metal salt defoaming agent, an anionic surfactant, and a peroxycarboxylic acid stabilizing agent, wherein the stabilizing agent is a picolinic acid or a compound having the following Formula (IA):
wherein R 1 is OH or —NR 1a R 1b , wherein R 1a and R 1b are independently hydrogen or (C 1 -C 6 )alkyl; wherein R 2 is OH or —NR 2a R 2b , wherein R 2a and R 2b are independently hydrogen or (C 1 -C 6 )alkyl; wherein each R 3 is independently (C 1 -C 6 )alkyl, (C 2 -C 6 )alkenyl or (C 2 -C 6 )alkynyl; and n is a number from zero to 3; or a salt thereof;
or a compound having the following Formula (IB):
wherein R 1 is OH or wherein —NR 1a R 1b , and R 1b are R 1b independently hydrogen or (C 1 -C 6 )alkyl; wherein R 2 is OH or —NR 2a R 2b , wherein R 2a and R 2b are independently hydrogen or (C 1 -C 6 )alkyl; wherein each R 3 is independently (C 1 -C 6 )alkyl, (C 2 -C 6 )alkenyl or (C 2 -C 6 )alkynyl; and n is a number from zero to 3; or a salt thereof, wherein the stabilizing agent delays or prevents the peroxycarboxylic acid from exceeding its self-accelerating decomposition temperature (SADT).