Methods for preparing phenolic branched chain alkyl fatty acids or esters thereof and methods for killing microorganisms
Inventors
Lew, HELEN N. • Wagner, Karen • Fan, Xuetong • Nunez, Alberto • Moreau, Robert A. • Haas, Michael J. • YAN, ZONGCHENG
Assignees
US Department of Agriculture USDA
Publication Number
US-10071946-B2
Publication Date
2018-09-11
Expiration Date
2036-03-01
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Abstract
Disclosed are methods for preparing phenolic branched chain fatty acids or alkyl esters thereof, involving subjecting in a pressurized container (a) at least one phenolic compound, (b) unsaturated fatty acids having 6 to 25 carbon atoms, alkyl esters thereof, or mixtures thereof, and (c) H-ferrierite zeolite catalyst in the presence of distilled water or alcohol and a nitrogen atmosphere at a temperature of about 100° C. to about 400° C. and a pressure of about 10 to about 1000 psi, and isolating saturated phenolic branched chain fatty acids or alkyl esters thereof or mixtures thereof. Also disclosed are methods for killing microorganisms on or in an object, involving contacting said object with an effective microorganisms killing amount of a composition comprising phenolic branched chain fatty acids or alkyl esters thereof, and optionally a carrier; the phenolic branched chain fatty acids or alkyl esters thereof may be produced by the methods described herein.
Core Innovation
The invention discloses methods for preparing phenolic branched chain fatty acids or alkyl esters thereof by reacting at least one phenolic compound, unsaturated fatty acids having 6 to 25 carbon atoms or their alkyl esters, and H-ferrierite zeolite catalyst in a pressurized container. The reaction is conducted in the presence of distilled water or alcohol under a nitrogen atmosphere at temperatures from about 100° C. to about 400° C. and pressures from about 10 to about 1000 psi. The process yields saturated phenolic branched chain fatty acids or alkyl esters with a yield greater than about 70 wt %, wherein at least one phenolic group is attached to the fatty acid alkyl chain.
The problem addressed arises from the instability of carbon-carbon double bonds in fatty acids of vegetable oils and animal fats at elevated temperatures, which limits their applications. Existing biobased fluids exhibit unique properties but there is a need for new chemical classes with improved versatility and enhanced properties such as lubricity, thermal and oxidative stability, biodegradability, and low-temperature fluidity. Previous methods for producing branched chain fatty acids use homogeneous catalysts or stoichiometric reagents and often result in mixtures with moderate yields and non-recyclable catalysts. There's a need to develop new synthetic approaches that improve production of aryl-branched-chain fatty acids while minimizing byproducts like dimers and lactones.
The disclosed methods utilize a heterogeneous catalytic approach with H-ferrierite zeolite catalyst, operating under defined reaction conditions involving phenolic compounds, unsaturated fatty acids or their esters, water or alcohol, and nitrogen atmosphere under pressure and heat. This single-step process yields high conversion and selectivity towards phenolic branched chain fatty acids or esters with minimal formation of byproducts. The phenolic branched chain fatty acids produced exhibit antimicrobial properties, especially against Gram-positive bacteria, providing a novel use for these compounds in killing microorganisms.
Claims Coverage
The patent contains one independent claim covering a method for preparing phenolic branched chain fatty acids or alkyl esters thereof using specified reactants and conditions; it includes multiple inventive features related to reaction parameters, catalyst use, and product characteristics.
Method for preparing phenolic branched chain fatty acids or alkyl esters thereof
Subjecting at least one phenolic compound, unsaturated fatty acids having 6 to 25 carbon atoms (or their alkyl esters), and H-ferrierite zeolite catalyst in a pressurized container with distilled water or alcohol under nitrogen atmosphere at a temperature of about 100° C. to about 400° C. and pressure about 10 to about 1000 psi, and isolating saturated phenolic branched chain fatty acids or alkyl esters thereof, wherein the ratio of phenolic compound to unsaturated fatty acids or alkyl esters is about 100 to about 1, and the yield of said saturated phenolic branched chain fatty acids is greater than about 70 wt % with at least one phenolic group on the fatty acid alkyl chain.
Process parameters for improved product yield and catalyst management
The process uses unsaturated fatty acids with 10 to 22 carbon atoms preferably 16 to 22, achieves a conversion greater than about 85%, yield of dimers less than about 15 wt %, and yield of linear chain fatty acid less than about 18 wt %. The catalyst, H-ferrierite zeolite, especially H+-ferrierite-NH4, can be recycled and regenerated by washing with acid solution or solvent, heating, drying at about 115° C. for about 20 hours, and calcination at about 500° C. for at least 5 hours.
Production of phenolic branched chain fatty acids or esters with varying phenol substitutions
The process produces phenolic branched chain fatty acids or alkyl esters having one, two, or three phenolic groups on the fatty acid alkyl chain, achieved by using at least two phenolic compounds in the reaction.
These inventive features together define the method of producing high-yield saturated phenolic branched chain fatty acids or their esters with controlled phenolic substitutions on the alkyl chain, using H-ferrierite zeolite catalyst under specified temperature, pressure, and reactant ratio conditions, with catalyst recyclability and regeneration steps to enhance process sustainability.
Stated Advantages
The method achieves high yields (>70 wt %) of saturated phenolic branched chain fatty acids or esters while minimizing byproducts such as dimers and lactones.
The use of a heterogeneous H-ferrierite zeolite catalyst allows for catalyst recyclability and reuse, improving process efficiency and sustainability.
The produced phenolic branched chain fatty acids exhibit strong antimicrobial properties, particularly against Gram-positive bacteria, enabling effective killing of microorganisms.
The process allows for manufacturing products with enhanced properties, such as lower melting points due to branched structures, improving low-temperature fluidity for industrial applications.
Documented Applications
Use of phenolic branched chain fatty acids or alkyl esters thereof to kill microorganisms on or in objects including surfaces, foods, beverages, food-packages, cosmetics, pharmaceuticals, sanitizers, and kitchen countertops.
Antimicrobial treatment of foods such as meat, poultry, seafood, eggs, nuts, fruits, vegetables, and particularly fresh-cut produce including peeled or sliced fruits and vegetables.
Potential use of these compounds to treat skin diseases and infections caused by Propionibacterium acnes.
Applications in biobased industrial fluids requiring properties like superior lubricity, thermal and oxidative stability, corrosion inhibition, oxidation stability, rust inhibition, and stain resistance in textiles and lubricants.
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