Reduced odor esters and process for producing same

Details Reduced odor esters and process for producing same Reduced odor esters and process for producing same

2000-02-04

2003-10-21

Barts, Samuel (Department: 1623)

Organic compounds -- part of the class 532-570 series

Organic compounds

Fatty compounds having an acid moiety which contains the...

C554S176000, C554S182000, C554S227000, C560S103000, C560S112000, C560S248000

Reexamination Certificate

active

06635775

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to reduced odor or odor-free esters, and more particularly to odor-free C12-C15 alkyl benzoate esters, octanoate esters, glycol dibenzoate esters, and other emollient esters, their process of manufacture and their use in cosmetics and personal care products as carriers or vehicles, or a diluents, solvents, plasticizers, emollients and solubilizers.
2. Description of the Related Art
Esters are known for a variety of different applications for cosmetic, pharmaceutical and medicinal purposes.
Numerous references describe the production and use of benzoic acid esters. None of these references teach or suggest the specific novel reduced odor or odorless benozate esters of this invention or the use of these and other reduced odor benzoate esters in cosmetics and personal care products.
For example, benzoate esters of certain alcohols and alcohol mixtures and their uses are disclosed in assignee's U.S. Pat. Nos. 4,323,694; 4,322,545; and 4,275,222, all to Scala; and U.S. Pat. Nos. 4,791,097; 5,270,461; and 5,271,930, all to Walele et al. The disclosures of these patents are incorporated herein by reference.
U.S. Pat. Nos. 4,323,694; 4,322,545; and 4,275,222 to Scala disclose benzoic acid esters and processes for making same, using methane sulfonic acid as a catalyst at temperatures of about 160° C. to 175° C. The catalyst containing crude ester is washed and dried. Although there is no specific teaching of such washings in Scala, the industry practice is to neutralize any residual acidity with an alkali water wash. The ester is then further washed, as necessary, and dried. The Scala patents do not disclose using stannous oxalate as a catalyst, running the reaction at very high temperatures (220° C. or more), or removal of the catalyst as a process improvement to improve the odor of the resultant esters.
U.S. Pat. Nos. 4,791,097; 5,270,461; and 5,271,930 to Walele et al. disclose benzoic acid esters and processes for making same. The processes disclose reacting benzoic acid with an alcohol, using a catalyst, heating and then cooling, and collecting distillate. The mixture was subsequently treated with, among other things, hydrogen peroxide, and heated at 80° C.-100° C. The ester component was collected, washed with neutralization, and then refined by washing and drying.
U.S. Pat. No. 2,997,494 to Brown discloses a method of preparing vinyl esters of carboxylic acids.
U.S. Pat. No. 3,843,719 to Brady discloses a process for preparing esters of carboxylic acids.
U.S. Pat. No. 4,304,925 to Watanabe et al. discloses a process for obtaining esters by reacting an organic carboxylic acid or its anhydride with an alcohol in the presence of an organometallic compound as a catalyst. There is no recognition of steps taken specifically to improve the odor of the esters.
U.S. Pat. No. 4,506,091 to Deardorff discloses a method for refining esters without the necessity of washing procedures. Improvement of the odor of the ester is not contemplated or recognized.
U.S. Pat. No. 5,302,746 to Koono et al. discloses a process for producing a carboxylic acid ester, using a countercurrently contacting column for neutralization.
U.S. Pat. No. 5,693,316 to Pereira et al. discloses fatty alkoxylate esters of aliphatic and aromatic dicarboxylic acids.
U.S. Pat. No. 5,783,173 to Bonda et al. discloses a sun-screen composition containing a UV-B dibenzoyl-methane derivative such as PARSOL 1789, and a stabilizer/solubilizer for the dibenzoylmethane derivative, and mixtures thereof.
However, among the foregoing patents, none have the unique properties of the ester compositions described and claimed herein. None disclose or suggest a process for the production of esters and emollient esters which are odorless or which have extremely low odor due to the absence of odor-causing species such as aldehydes, carbonyl compounds, and the like. This is a vital property in numerous applications, as the esters may be incorporated into personal care products, where absence of odor is critical to consumer acceptance.
This is due in part to the failure of prior processes to recognize that removal of the catalyst improves the odor, and to the use of certain unsuitable catalysts. For instance, the Scala patents referred to above use Methane Sulfonic Acid (MSA) as a catalyst. The problem with using MSA as a catalyst is that it is soluble in the organic reactants. MSA dissolves in the organic matter during reaction and cannot be physically removed by filtration from the reaction mix. It is not heterogeneous as is the case with stannous oxalate and metal oxides. However, it is neutralized in the neutralization/washings which follow subsequent to the esterification reaction. So even after neutralization and washing, odorous esters are formed because the intrinsic odor from the raw materials remains. Another problem with MSA is that the reaction cannot be run at high temperatures; exceeding temperatures of about 170° C. to 175° C. results in formation of chocolate-colored organic matter. It has been found by applicants that the darker the ester product, generally the worse the odor. Esters made using MSA as a catalyst have been found by applicants to be odorous.
In developing formulations for personal care products, it is critical to utilize a product that lacks odor. Many emollients have a characteristic obnoxious odor that is difficult to mask. Masking odors is an inordinately difficult and expensive task. Known methods of producing esters and ester-emollients result in esters which are odorous, i.e., they have an MFL, a minimum fragrance level. This is a disadvantage because perfumes must then be added to mask or overcome the MFL. Additionally and/or alternatively, the esters are deodorized by various methods including filtering, bleaching clays, or steam distilling the esters. Masking the obnoxious odors of many emollients is both difficult and expensive.
The disadvantages of the known methods of producing esters and emollient esters are overcome by the process of the present invention. Unexpectedly, the esters of the invention are odorless or have a very small MFL, avoiding the need for perfumes and deodorization.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process or producing esters and emollient esters which have a low odor, or MFL, or which are odorless, due to the absence of odor causing species such as aldehydes, carbonyl compounds, and the like.
It is another object of the invention to provide a process for making reduced odor or odorless esters and emollient esters for use in cosmetics and personal care products.
It is yet another object of the invention to provide a process for making reduced odor or odorless esters and emollient esters for use in products where the addition of perfumes is objectionable.
It is a further object of the invention to provide a process for making esters and emollient-esters for use in cosmetics and personal care products which reduces the need for perfumes in cosmetics and personal care products.
Yet another object of the invention is to provide a method for producing esters and emollient esters which obviate the need for extraneous filtration or deodorizing techniques to remove odor.
Another object of the invention is to provide a method of producing reduced odor or odorless cosmetics or personal care products using certain specific benzoic acid esters.
It is another object of the invention to provide low-odor or non-odorous esters and emollient esters by reducing or substantially eliminating odor causing species.
Yet another object of the invention is to provide novel esters which may serve as emollient's and which may also modify the odor characteristics of the products in which they are used.
It is another object of the invention to provide reduced odor or non-odorous esters and ester emollients for use in products where the use of perfumes is objectionable.
It is another object of the invention to provide reduced odor or non-odorous esters and ester

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