Prior art — US Patent 9737072

Based on the "References Cited" section of US patent 9,737,072, the following prior art is identified as most relevant to the patent's claims.

Analysis of Prior Art for US Patent 9,737,072

1. WO 01/46519 A1

Full Citation: WO 01/46519 A1, "ON-SITE GENERATION OF PERACETIC ACID", to Nalco Company (assignee for Ecolab Inc.).
Dates: Filed: 2000-12-20; Published: 2001-06-28.
Brief Description: This international application discloses a process for generating peracetic acid (PAA) on-site. The method involves metering an aqueous solution of hydrogen peroxide and simultaneously co-metering a solid, dry source of an acetyl precursor, specifically tetraacetylethylenediamine (TAED), from a hopper into an agitated tank. Aqueous sodium hydroxide is then introduced into an in-line static mixer with the suspension. The resulting mixture is passed through a coiled tubular reactor to manage the exothermic reaction and form PAA. The '072 patent itself discusses this reference, noting its disadvantages include "the difficulty of accurately metering a solid and a liquid simultaneously, and the high capital equipment cost" (Description, col. 4, lines 34-40).
Potential Anticipation of Claims:
- Claims 1 & 14 (Methods): This reference teaches the core concept of on-site, continuous generation of PAA via alkali-activated perhydrolysis of an acetyl precursor with hydrogen peroxide. It discloses combining a peroxide source, an acetyl precursor, and sodium hydroxide in water to form a PAA solution. However, it does not anticipate claims 1 or 14 because it explicitly teaches using a solid acetyl precursor (TAED) that is metered separately from the hydrogen peroxide. In contrast, the '072 patent claims a method starting with a pre-mixed liquid solution of hydrogen peroxide and the liquid acetyl precursor triacetin. This use of a single, stable liquid precursor solution simplifies the process and equipment compared to the solid-liquid metering system in WO 01/46519 A1.
- Claim 20 (Composition): This reference does not disclose or suggest the stable liquid composition of 23-40% hydrogen peroxide and 20-52% triacetin as claimed.

2. US 3,432,546 A

Full Citation: US Patent 3,432,546, "Preparation of peracetic acid", to Union Carbide Corp.
Dates: Filed: 1966-07-28; Published: 1969-03-11.
Brief Description: This patent describes a continuous process for producing PAA by reacting hydrogen peroxide with acetic anhydride in a tubular reactor. The process uses ammonium hydroxide as a catalyst.
Potential Anticipation of Claims:
- Claims 1 & 14 (Methods): This patent discloses a continuous, on-site generation method but uses fundamentally different reactants. It relies on acetic anhydride as the acetyl source, not triacetin. Furthermore, it uses an ammonium hydroxide catalyst. As stated in the '072 patent background, ammonium hydroxide is an "undesirable contaminant" in PAA products intended for food, dairy, and medical applications (Description, col. 4, lines 1-6), which is a primary target for the '072 invention. Therefore, it does not anticipate the claims.
- Claim 20 (Composition): This reference does not disclose the claimed composition of hydrogen peroxide and triacetin.

3. US 2009/0043132 A1

Full Citation: US Patent Application Publication 2009/0043132 A1, "METHOD FOR GENERATING PERACETIC ACID IN SITU", Inventor: Michael G. Bailey.
Dates: Filed: 2007-08-10; Published: 2009-02-12.
Brief Description: This application describes a method for generating PAA in situ within a body of water requiring treatment. The method involves introducing hydrogen peroxide into a sidestream of the water, followed by the introduction of acetic anhydride. The reaction forms PAA directly within the sidestream, which is then returned to the main body of water.
Potential Anticipation of Claims:
- Claims 1 & 14 (Methods): This reference is relevant as it pertains to on-site PAA generation. However, it is distinguished by its use of acetic anhydride as the acetyl precursor, which the '072 patent identifies as "expensive, very corrosive, an irritant, and highly flammable" (Description, col. 4, lines 20-22). The '072 patent's use of non-toxic, non-flammable triacetin is a key distinction.
- Claim 20 (Composition): This reference does not teach or suggest the stable liquid peroxide-triacetin composition.

4. US 5,122,538 A

Full Citation: US Patent 5,122,538, "Preparation of percarboxylic acids", to Interox International.
Dates: Filed: 1991-03-27; Published: 1992-06-16.
Brief Description: This patent discloses a method for making non-equilibrium PAA by passing a solution of acetic acid and hydrogen peroxide through a column packed with a sulfonic acid ion-exchange resin, which acts as a catalyst.
Potential Anticipation of Claims:
- Claims 1 & 14 (Methods): This method involves on-site PAA generation but uses a different chemical pathway. It employs an acid catalyst (ion-exchange resin) to react acetic acid with hydrogen peroxide, whereas the '072 patent uses a base (alkali hydroxide) to induce the perhydrolysis of triacetin. The '072 patent background specifically critiques this resin-based method for requiring large, expensive resin beds that are subject to oxidative degradation (Description, col. 3, lines 46-56).
- Claim 20 (Composition): Does not disclose the claimed composition.

Disclaimer: This analysis is for informational purposes only and does not constitute legal advice. The determination of patentability or anticipation is a legal conclusion that can only be made by a patent examiner or a court.