E.i. Dupont De Nemours and Company

Leon S Scott

John Joseph Ostermaier

Michael Brian D'Amore

Emilio Enrique Bunel

Richard E Ernst

Anne Irisa Breikss

James D Verbsky

John D Super

William S Kalema

Peter A Bloxham

James Hastings

Chen-Chou Chiang

Roy W Sommers

Erik J Schaumann

Process for the recovery of a purified adiponitrile (ADN) from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine, utilizing two sequential distillations: (1) a first distillation in which the mixture is distilled in a distillation column at a head pressure that causes at least 7% of the ADN to go into the distillate, along with bishexamethylenetriamine (BHMT) and 2-cyanocyclopentylideneimine (CPI), and (2) a second distillation in which the distillate from the first distillation is distilled in a second distillation column at a head pressure sufficient to cause minimum-temperature azeotropy between ADN and BHMT, thereby allowing the majority of the BHMT and CPI to be removed from the second distillation as distillate, and ADN, substantially free of both BHMT and CPI, to be removed as bottoms.

Recovery of adiponitrile from a mixture of adiponitrile, aminocapronitrile and hexamethylenediamine

A method for separating a mixture of hexamethylenediamine, aminocapronitile and polarographically reducible impurities using fractional distillation in which the temperature in the rectifying zone of a distillation column varies sigmoidally along its length to force a major portion of the PRI to co-distill with the aminocapronitrile.

Recovery of hexamethylenediamine (HMD) with low polarographically reducible impurities (PRI) from mixtures of HMD, aminocapronitirle and PRI

A process for removing precursors, such as low boiling alkyl glycols (e.g., ethylene glycol and/or 1,2-propylene glycol), to undersirable color forming acetal impurities (e.g., 1,3 -dioxolane and 4-methyl-1,3-dioxolane) from technical grade 1,4-butanediol/2-methyl-1,4-butanediol mixtures and the like by distillative topping of the diol mixture prior to ring closing cyclization to corresponding tetrahydrofuran/3-methyl tetrahydrofuran mixture and subsequent polymerization to polytetramethylene glycol ether polymers. Such a process is useful to produce THF and PTMEG having a APHA color index of nearly zero.

Method for controlling color formation during polytetramethylene ether

Preparation of 3-pentenoic acid by the reaction of 3-pentenoylchloride, water and butadiene. 3-chloro-1-butene and 1-chloro-2-butene are also formed. Preferably the 3-pentenoylchloride is formed by the reaction of chlorobutene with carbon monoxide using a palladium catalyst.

Preparation of 3-pentenoic acid and a catalyst therefore

Extraction of valeric and/or caproic acid from an aqueous solution containing adipic acid and/or methyl glutaric acid using an organic solvent is enhanced by carrying out the process using an extraction-enhancing acid, such as acetic or isobutyric acid, which is soluble in the organic solvent.

Enhanced extraction of valeric acid or caproic acid from aqueous mixtures

Process for the preparation of fiber-grade terephthalic acid by continuously oxidizing paraxylene while vaporizing a portion of the contents of the reactor. Fiber-grade terephthalic acid is produced by maintaining (1) a temperature of at least 210.degree. C., (2) a molecular oxygen content of the noncondensables in the vapor withdrawn from the reactor in the range 3.0-6.0%, (3) a water level of the contents of the oxidizer in the range 5.0-17.0%, (4) a mole ratio of sodium to cobalt plus manganese in the range 0.06-2.0 in the reactor, (5) a mole ratio of cobalt to manganese in the range 0.5-5.0 (6) an organic burn in the range 8.0-15.0 burn units and (7) a productivity in the range 0.45-1.45 pounds of terephthalic acid per minute per 100 pounds of reactor contents.

Growing community of inventors

Wilmington, DE, United States of America

Leon S Scott