Abstract: Degradable materials are provided that may be utilized in various wellbore treatment fluids, such as hydraulic fracturing fluids. In particular, the degradable materials can be formed from cellulose esters that are capable of effectively degrading at specific rates when exposed to the aqueous environments commonly found in wellbores. More particularly, the degradable materials can be in the form of degradable fibers that are formed from the cellulose esters described herein.

Abstract: The present invention comprises the use of sulfite additives to reduce discoloration of L-ascorbic acid produced from acid or aqueous solutions of 2-keto-L-gulonic acid. In one aspect, the present invention comprises a continuous process for producing L-ascorbic acid from an aqueous solution of 2-keto-L-gulonic acid. The use of sulfite additives reduces product stream color and improves product recovery by binding to high molecular weight reaction by-products. In a continuous process, the reaction stream is separated from residual sulfite and sulfite-bound by-products to produce a product stream enriched in aqueous ascorbic acid for recovery, and an enriched 2-keto-L-gulonic acid stream which is recycled to the reactor. The in situ use of sulfite additives during the reaction increases the overall yield of L-ascorbic acid, with no loss in selectivity of the synthesis.

Abstract: A process for recovering a desired organic acid from a solution includes the steps of: providing an aqueous solution including at least one desired organic acid or its acid anion; adjusting the proton concentration in the aqueous solution to a desired level, with the desired proton concentration being selected, at least in part, by the amount of available protons needed to associate with the acid anions of the desired organic acid(s) to be recovered and/or acid anions that are weaker than the desired organic acids; and recovering at least a portion of the at least one desired organic acid from the aqueous phase. The desired proton concentration can be based on the amount of available protons being greater than, less than or substantially equal, to the amount of protons needed to associate with the anion of the desired organic acid(s) and acid anions that are weaker than the desired organic acid(s).

Abstract: The present invention provides methods and an apparatus for the manufacture of an L-ascorbic acid product in high yield by direct conversion of an aqueous solution containing 2-keto-L-gulonic acid by contact with an acid catalyst or under thermal self-catalyzed conditions at a conversion level that maximizes the formation of L-ascorbic acid and minimizes decomposition of the L-ascorbic acid thus formed. The separation process for L-ascorbic acid and KLG is operated in such a way that an efficient separation process allows the majority of the KLG to be recycled for further conversion. The product stream from the separation process is then subjected to a recovery step to obtain crystalline L-ascorbic acid product.

Abstract: Disclosed is a process wherein a solution of a carboxylic acid in a first solvent and an alcohol are fed to a simulated moving bed reactor (SMBR) containing a solid(s) to produce a first stream comprising a solution of an ester of the carboxylic acid and the alcohol and a second stream comprising the first solvent. The solid(s) present in the SMBR facilitates the esterification reaction and the separation of the first solvent from the carboxylic acid. The process is particularly valuable for the preparation of an alkanol solution of an alkyl 2-keto-L-gulonate ester (AKLG) from an aqueous fermentation broth containing dissolved 2-keto-L-gulonic acid (KLG) by feeding the fermentation broth and an alkanol to a simulated moving bed reactor which contains a solid acidic esterification catalyst to produce a stream comprising an alkanol solution of an ALKG. The alkanol solution of an ALKG may be used directly to convert the ALKG to ascorbic acid (Vitamin C).

Abstract: The present invention provides methods and an apparatus for the manufacture of an L-ascorbic acid product in high yield by direct conversion of an aqueous solution containing 2-keto-L-gulonic acid by contact with an acid catalyst or under thermal self-catalyzed conditions at a conversion level that maximizes the formation of L-ascorbic acid and minimizes decomposition of the L-ascorbic acid thus formed. The separation process for L-ascorbic acid and KLG is operated in such a way that an efficient separation process allows the majority of the KLG to be recycled for further conversion. The product stream from the separation process is then subjected to a recovery step to obtain crystalline L-ascorbic acid product.

Abstract: The present invention comprises the use of sulfite additives to reduce discoloration of L-ascorbic acid produced from acid or aqueous solutions of 2-keto-L-gulonic acid. In one aspect, the present invention comprises a continuous process for producing L-ascorbic acid from an aqueous solution of 2-keto-L-gulonic acid. The use of sulfite additives reduces product stream color and improves product recovery by binding to high molecular weight reaction by-products. In a continuous process, the reaction stream is separated from residual sulfite and sulfite-bound by-products products to produce a product stream enriched in aqueous ascorbic acid for recovery, and an enriched 2-keto-L-gulonic acid stream which is recycled to the reactor. The in situ use of sulfite additives during the reaction increases the overall yield of L-ascorbic ascorbic acid, with no loss in selectivity of the synthesis.

Abstract: A process for recovering a desired organic acid from a solution includes the steps of: providing an aqueous solution including at least one desired organic acid or its acid anion; adjusting the proton concentration in the aqueous solution to a desired level, with the desired proton concentration being selected, at least in part, by the amount of available protons needed to associate with the acid anions of the desired organic acid(s) to be recovered and/or acid anions that are weaker than the desired organic acids; and recovering at least a portion of the at least one desired organic acid from the aqueous phase. The desired proton concentration can be based on the amount of available protons being greater than, less than or substantially equal, to the amount of protons needed to associate with the anion of the desired organic acid(s) and acid anions that are weaker than the desired organic acid(s).

Abstract: A process for recovering an organic acid or a metal salt thereof includes contacting an alcoholic phase containing one or more organic acid(s) or metal salt(s) thereof with water under conditions effective to provide an aqueous phase containing a portion of the organic acid(s) or metal salt(s) thereof. The aqueous phase does not contain substantial amounts of the alcohol(s). This process can also include recovery of the organic acid(s) or metal salt(s) thereof from the aqueous phase.