Reduced odor esters and process for producing same

Abstract

An improved process for preparing reduced-odor or odorless esters, preferably benzoate esters, octanoate esters, aliphatic emollient esters and glycol dibenzoate esters. The improved process comprises, in part, removing the esterification catalyst from the crude ester after the esterification reaction is substantially complete, before neutralization of acidity. The resultant ester compositions are odorless or have substantially reduced odor as compared to commercially available esters.

We claim:  
     
         1 . A method of reducing or eliminating odor in an ester composition comprising removing the esterification catalyst from the crude ester before neutralization of acidity.  
     
     
         2 . In a process for preparing reduced-odor esters comprising reacting an acid with an alcohol in the presence of an effective amount of a catalyst, and removing water of esterification until esterification is substantially complete, the improvement which comprises removing said catalyst after the esterification reaction is substantially complete.  
     
     
         3 . In a process for preparing odorless, colorless esters from an esterification reaction mixture obtained by reacting an acid and an alcohol in the presence of an effective amount of a catalyst, which comprises adding alkali to the esterification reaction mixture and washing the ester, the improvement, wherein prior to addition of alkali, removing said catalyst from said reaction mixture, and wherein after neutralization with said alkali is completed, contacting the wet, crude ester with a bleaching agent.  
     
     
         4 . The process of  claim 3  wherein said odorless esters are benzoate esters, octanoate esters, aliphatic emollient esters, or glycol dibenzoate esters, wherein said acid is selected from the group consisting of benzoic acid, ethylhexanoic acid, and linear or branched carboxylic acids with 4 to 22 carbon atoms, and wherein said alcohol has from 3 to 22 carbon atoms.  
     
     
         5 . In a process for preparing reduced-odor benzoate esters from an esterification reaction mixture obtained by reacting benzoic acid with an alcohol in the presence of an effective amount of a catalyst, which comprises the steps of: 
 heating said reaction mixture;    collecting distillate comprising the water of reaction;    neutralizing and washing the acidity of said reaction mixture with at least one alkali;    drying said ester; and    filtering the refined ester product;    the improvement comprising removing said catalyst from said reaction mixture after the reaction is complete, and before neutralization.    
     
     
         6 . The process of  claim 5  wherein said catalyst comprises an organometallic compound or metal oxide compound.  
     
     
         7 . The process of  claim 5  wherein said catalyst is stannous oxalate or zinc oxide.  
     
     
         8 . The process of  claim 5  wherein said catalyst is removed by filtration.  
     
     
         9 . The process of  claim 5  wherein in said neutralization step, the filtered, crude ester is neutral washed with at least stoichiometric amounts of alkali.  
     
     
         10 . The process of  claim 5  wherein said alkali comprises an alkali metal carbonate or alkali metal hydroxide.  
     
     
         11 . The process of  claim 5  wherein after said neutralization is completed, contacting the wet, crude ester with a bleaching agent.  
     
     
         12 . The process of  claim 5  wherein said bleaching agent is hydrogen peroxide.  
     
     
         13 . The process of  claim 5  wherein said wet, crude ester is contacted with a bleaching agent in a first or subsequent washing step, after neutralization is complete.  
     
     
         14 . The process of  claim 5  wherein said alcohol comprises from 3 to 22 carbon atoms.  
     
     
         15 . The process of  claim 5  wherein said alcohol preferably comprises 12 to 15 carbon atoms.  
     
     
         16 . The process of  claim 5  wherein said alcohol is most preferably Neodol 25.  
     
     
         17 . The process of  claim 5  wherein said crude ester has an acidity of no more than 10 mg KOH/g.  
     
     
         18 . The process of  claim 5  further comprising pretreating said alcohol with sodium borohydride before reacting with benzoic acid and before contacting with said catalyst.  
     
     
         19 . The process of  claim 5  wherein said neutralization wash further comprises at least one salt selected from the group consisting of sodium chloride, sodium sulfate, potassium chloride and potassium sulfate.  
     
     
         20 . The process of  claim 5  further comprising the step of cooling said reaction mixture after said reaction is substantially complete and before said neutralization step.  
     
     
         21 . The process of  claim 5  comprising the step of further washing the resulting crude ester after said neutralization and washing step.  
     
     
         22 . The process of  claim 21  wherein at least one salt selected from the group consisting of sodium chloride, sodium sulfate, potassium chloride, and potassium sulfate is added in at least one of said washing steps.  
     
     
         23 . The process of  claim 5  wherein distillate is collected until sterification is substantially complete.  
     
     
         24 . The process of  claim 5  wherein said process is a batch process.  
     
     
         25 . The process of  claim 5  wherein said process is a continuous process.  
     
     
         26 . The process of  claim 25  wherein said process is conducted in a continuous extractor.  
     
     
         27 . A reduced odor benzoic acid ester prepared by the process of  claim 5 .  
     
     
         28 . A reduced odor C12-C15 alkyl benzoate ester prepared by the process of  claim 5 .  
     
     
         29 . A non-aqueous composition for topical application comprising one or more active ingredients and a benzoic acid ester emollient agent prepared by the process of  claim 5 .  
     
     
         30 . The composition of  claim 29  wherein said one or more active ingredients are selected from the group consisting of sunscreens, moisturizers, film formers, detergents, emulsifiers, emollients, thickening agents, antiseptic agents, conditioning agents, deodorant actives, and reducing agents.  
     
     
         31 . An aqueous composition comprising one or more active ingredients and a benzoic acid ester emollient agent prepared by the process of  claim 5 .  
     
     
         32 . The composition of  claim 31  wherein said one or more active ingredients are selected from the group consisting of sunscreens, moisturizers, film formers, detergents, emulsifiers, emollients, thickening agents, antiseptic agents, conditioning agents, deodorant actives, and reducing agents.  
     
     
         33 . In a process for preparing reduced-odor octanoate esters from an esterification reaction mixture obtained by reacting ethylhexanoic acid with an alcohol in the presence of an effective amount of a catalyst, which comprises the steps of: 
 heating said reaction mixture;    collecting distillate comprising the water of reaction;    neutralizing and washing the acidity of said reaction mixture with at least one alkali;    drying said ester; and    filtering the refined ester product;    the improvement comprising removing said catalyst from said reaction mixture after the reaction is complete, and before neutralization.    
     
     
         34 . The process of  claim 33  wherein said alcohol comprises from 3 to 22 carbon atoms.  
     
     
         35 . The process of  claim 33  wherein said alcohol preferably comprises 12 to 15 carbon atoms.  
     
     
         36 . The process of  claim 33  wherein said alcohol is preferably Neodol 25.  
     
     
         37 . The process of  claim 33  wherein said catalyst is stannous oxalate or zinc oxide.  
     
     
         38 . The process of  claim 33  wherein after said neutralization is completed, contacting the wet, crude ester with a bleaching agent.  
     
     
         39 . A reduced odor octanoate ester prepared by the process of  claim 33 .  
     
     
         40 . In a process for preparing reduced odor aliphatic, emollient esters from an esterification reaction mixture obtained by reacting a carboxylic acid with an alcohol in the presence of an effective amount of a catalyst, which comprises the steps of: 
 heating said reaction mixture;    collecting distillate comprising the water of reaction;    neutralizing and washing the acidity of said reaction mixture with at least one alkali;    drying said ester; and    filtering the refined ester product;    the improvement comprising removing said catalyst from said reaction mixture after the reaction is complete, and before neutralization.    
     
     
         41 . The process of  claim 40  wherein said alcohol comprises from 3 to 22 carbon atoms and wherein said carboxylic acid comprises linear or branched carboxylic acids with 4 to 22 carbon atoms.  
     
     
         42 . The process of  claim 40  wherein said alcohol preferably comprises 12 to 15 carbon atoms.  
     
     
         43 . The process of  claim 40  wherein said alcohol is preferably Neodol 25.  
     
     
         44 . The process of  claim 40  wherein said catalyst is stannous oxalate or zinc oxide.  
     
     
         45 . The process of  claim 41  wherein after said neutralization is completed, contacting the wet, crude ester with a bleaching agent.  
     
     
         46 . A reduced odor octanoate ester prepared by the process of  claim 40 .  
     
     
         47 . In a process for preparing reduced odor glycol dibenozate esters from an esterification reaction mixture obtained by reacting a glycol with benzoic acid in the presence of an effective amount of a catalyst, which comprises the steps of: 
 heating said reaction mixture;    collecting distillate comprising the water of reaction;    neutralizing and washing the acidity of said reaction mixture with at least one alkali;    drying said ester; and    filtering the refined ester product;    the improvement comprising removing said catalyst from said reaction mixture after the reaction is complete, and before neutralization.    
     
     
         48 . The process of  claim 47  wherein said glycol comprises from 3 to 12 carbon atoms.  
     
     
         49 . The process of  claim 47  wherein said glycol preferably comprises 6 to 12 carbon atoms.  
     
     
         50 . The process of  claim 47  wherein said glycol is preferably dipropylene glycol.  
     
     
         51 . The process of  claim 47  wherein said catalyst is stannous oxalate or zinc oxide.  
     
     
         52 . The process of  claim 47  wherein after said neutralization is completed, contacting the wet, crude ester with a bleaching agent.  
     
     
         53 . A reduced odor glycol dibenozate ester prepared by the process of  claim 47.