Abstract:
A continuous process for producing a nylon salt solution prepared using a liquid partially balanced acid solution enriched in dicarboxylic acid, and in particular adipic acid. The liquid feed is prepared by metering dicarboxylic acid powder, based on weight, from a loss-in-weight feeder to a feeding conduit that transfers the dicarboxylic acid powder into an in-line disperser; feeding a first feed stream of diamine to the in-line disperser to form a dispersion comprising between 32 wt. % and 46 wt. % dicarboxylic acid, between 11 wt. % and 15 wt. % diamine, and between 39 wt. % and 57 wt. % water, and heating the dispersion at temperature between 50 C and 60 C to form a partially balanced acid solution. A nylon salt solution is prepared from the liquid partially balanced acid solution and continuously withdrawn into a storage tank. The nylon salt solution has a uniform pH and is suitable for producing nylon polymers.
Abstract:
A process for producing a partially balanced acid solution that involves metering dicarboxylic acid powder, based on weight, from a loss-in-weight feeder to a feeding conduit that transfers the dicarboxylic acid powder at a low variability feed rate into an in-line disperser, adding a first feed stream of diamine to the in-line disperser in an amount sufficient to form the partially balanced acid solution having a solids content of less than 60%, and storing the partially balanced acid solution at a temperature to maintain the dissolved dicarboxylic acid and to prevent formation of a slurry. The partially balanced acid solution may be used as a feed solution to prepare a nylon salt solution. Process controls for the process are also disclosed.
Abstract:
Disclosed are nylon salt solution preparation processes including a trim diamine feed. The nylon salt solution is prepared by feeding a dicarboxylic acid monomer and a diamine monomer to a single continuous stirred tank reactor. The dicarboxylic acid is metered, based on weight, from a loss-in-weight feeder to the reactor. The nylon salt solution is formed continuously and has low variability from a target pH and/or a target salt solution concentration. The nylon salt solution is transferred directly to a storage tank, without further monomer addition, pH adjustment, or salt solution adjustment after exiting the continuous stirred tank reactor.