Abstract:
The present invention provides a process for the production of an aromatic dicarboxylic acid comprising the catalytic oxidation of a hydrocarbon precursor in an organic solvent, comprising the steps of: i) separating a vent gas from an oxidation stage into an organic solvent-rich liquid stream and a water-rich vapor stream in a distillation stage; and ii) separating an aqueous purification mother liquor comprising organic compounds from purified aromatic dicarboxylic acid crystals in a separation stage, characterized in that the process further comprises the steps of: iii) transferring the aqueous purification mother liquor from the separation stage to an extraction stage; iv) extracting said organic compounds from the aqueous purification mother liquor by contacting the aqueous purification mother liquor at a temperature of at least 90° C. with an organic liquid in the extraction stage to form an aqueous phase and an organic phase, wherein the concentration of said organic compounds in the aqueous phase is lower than the concentration of said organic compounds in the aqueous purification mother liquor; and v) transferring the aqueous phase to said distillation stage. The present invention further provides an apparatus for carrying out the process.
Abstract:
A solvent is at least partially separated from a catalyst. The catalyst comprises nickel and a bidentate phosphorus-containing ligand. The method for separation involves distilling a catalyst solution. The ratio of 2-pentenenitrile to 3-pentenenitrile in distillation column bottoms is controlled to reduce the amount of 3-pentenenitrile which is isomerized to form 2-methyl-3-butenenitrile. Isomerization of 3-pentenenitrile to 2-methyl-3-butenenitrile and subsequent isomerization of 2-methyl-3-butenenitrile to 2-methyl-2-butenenitrile, and/or hydrocyanation of 2-methyl-3-butenenitrile to methylglutaronitrile represents a loss in adiponitrile yield in a process for making adiponitrile.
Abstract:
The present invention provides an improved process for preferentially concentrating 2-methylglutaronitrile from mixtures comprising 2-methyl-glutaronitrile and other C6 nitriles having very close relative volatilities, for example, 2-ethylsuccinonitrile and adiponitrile, in a particular integrated, continuous distillative refining process, advantageously utilizing a carefully staged distillation apparatus train and by operating in an optimized window for effective separation.
Abstract:
Included are segmented polyurethane elastic fibers or spandex fibers, capable of bonding to polymer fiber such as nylon or polyamide fibers, in addition to bonding to itself, for apparel textile applications. More particularly the invention relates to bicomponent spandex fibers, with a heat resistant core and a heat sensitive sheath, spun from polymer solutions. The nylon fabrics containing such spandex fibers have enhanced stretch performance and improved surface appearance after heat treatment to activate the fusing and bonding between nylon fibers and spandex fibers.
Abstract:
The present disclosure provides methods and apparatuses estimating casting throughput during casting process to provide polyamide pellets. The method of estimating casting throughput of an extruded polyamide polymer comprises measuring an amount of casting water flowing in to a casting apparatus typically from two or more locations, measuring the temperature of the casting water flowing in, and measuring the temperature of the casting water flowing out. Additional steps include calculating a heat transfer between the casting water flowing in and the casting water flowing out using the measured amount, and correlating the heat transfer to the casting throughput.
Abstract:
The application relates to compositions for preparing articles, preforms or containers comprising composition for preparing articles, preforms or containers comprising a base polyester, a copolyester-ether, a transition metal-based oxidation catalyst, and a magnesium or lithium compound, wherein the weight ratio of the transition metal-based oxidation catalyst to the magnesium or lithium compound, on basis of the weight of the transition metal and the magnesium or lithium, is from 50:1 to 1:50.
Abstract:
Included herein is an articles and methods including a core spun yarn. The core spun yarn includes a sheath of hard fibers and two sets of elastic fibers wherein the sets of elastic fibers have different properties. The properties may differ in one or more ways such as having a different denier, composition or draft. One or both of the sets of elastic fibers can be precovered.
Abstract:
The invention provides a continuous process for the production of 3-pentenenitrile, comprising: (a) contacting, in a reaction zone, a hydrogen cyanide-containing feed, a 1,3-butadiene-containing feed, and a catalyst precursor composition, wherein the catalyst precursor composition comprises a zero-valent nickel and at least one multidentate phosphorus-containing ligand selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, and a mixed phosphorus-containing ligand or a combination of such members; and (b) maintaining a residence time sufficient to convert about 95% or more of the hydrogen cyanide and to produce a reaction mixture comprising 3-pentenenitrile and 2-methyl-3-butenenitrile, wherein the 2-methyl-3-butenenitrile concentration is maintained below about 15 weight percent of the total mass of the reaction mixture.