Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-09-13
2002-08-20
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C528S381000, C528S388000, C528S495000, C528S499000, C528S501000
Reexamination Certificate
active
06437024
ABSTRACT:
FIELD OF INVENTION
This invention relates to the field of processes utilizing methanol for extracting at least one polar organic compound, hereinafter referred to as “POC”, and at least one modifier compound from poly(arylene sulfide) polymer and oligomer streams.
BACKGROUND OF THE INVENTION
The production of poly(arylene sulfide), hereinafter referred to as P(AS), for a variety of industrial and commercial uses has been known for some time. P(AS) is moldable into various articles including, but not limited to, parts, films, and fibers by means of, for example, injection molding and extrusion molding techniques. These articles have utility in a variety of applications where heat and chemical resistance properties are desired. For example, P(AS) can be utilized as a material for preparing electrical and electronic parts and automotive parts.
Generally, high molecular weight P(AS) is prepared by contacting reactants comprising at least one dihalogenated aromatic compound, at least one POC, and at least one sulfur source, at least one base, and at least one modifier compound under polymerization conditions.
There are several problems associated with the current synthesis of P(AS) that cause the production expenses to be high. First, in both quench and flash P(AS) processes, modifiers utilized to synthesize the high molecular weight P(AS) are used once in the process and are not captured and recycled for subsequent use. This constitutes a great expense in the production of P(AS) due to the higher feedstock and waste disposal expense. Secondly, POC utilized in the process can be recovered, but often at a high cost. For example, n-hexanol is often utilized to extract N-methyl-2-pyrrolidone (NMP), a common POC. Operating the hexanol extractor system can require the handling of as much as 30 to 40 pounds of n-hexanol per pound of P(AS) produced causing high equipment and operational costs.
This invention provides a P(AS) process for recovering modifier compound and POC, which can greatly reduce the feedstock and disposal expense compared to current P(AS) processes. As a result of these improvements, the P(AS) produced by this invention has higher purity than that produced from current P(AS) processes.
SUMMARY OF INVENTION
It is an object of this invention to provide a process to recover at least one modifier compound and at least one POC from a quench process reaction mixture or flash process reaction mixture.
It is another object of this invention to provide a process that produces high purity, high molecular weight P(AS) product.
In accordance with one embodiment of the present invention, a process is provided to recover at least one POC and at least one modifier from a quench process reaction mixture comprising high molecular weight P(AS), low molecular weight P(AS), cyclic and linear P(AS) oligomers, at least one POC, at least one modifier compound, and an alkali metal halide by-product.
The process comprises:
1) contacting the quench process reaction mixture with methanol to produce a quench process methanol-rich mixture;
2) separating the quench process methanol-rich mixture to produce a high molecular weight P(AS) product, a recycle mixture, and optionally, a low molecular weight P(AS) stream;
wherein the recycle mixture comprises methanol, POC, and modifier compound;
wherein the low molecular weight P(AS) stream comprises low molecular weight P(AS) and cyclic and linear P(AS) oligomers.
In accordance with a second embodiment of this invention, a process is provided to recover at least one POC and at least one modifier from a quench process reaction mixture comprising high molecular weight P(AS), low molecular weight P(AS), cyclic and linear P(AS) oligomers, at least one POC, at least one modifier, and an alkali metal halide by-product. The process comprises:
1) contacting the quench process reaction mixture with at least one POC at a temperature sufficient to dissolve substantially all of the low molecular weight P(AS) and cyclic and linear oligomers to produce a quench process POC-rich mixture;
2) separating the quench process POC-rich mixture to produce a quench process solid stream and a quench process liquid stream;
wherein the quench process solid stream is in a substantially solid form and comprises high molecular weight P(AS), POC, modifier compound, and alkali metal halide by-product;
wherein the quench process liquid stream is in a substantially liquid form and comprises substantially all of the low molecular weight P(AS) and cyclic and linear P(AS) oligomers, POC, and modifier compound;
3) contacting the quench process solid stream with methanol to produce a quench process methanol-rich P(AS) product mixture; and
4) separating the quench process methanol-rich P(AS) product mixture to produce a high molecular weight P(AS) product and a recycle mixture;
wherein the recycle mixture comprises methanol, POC, and modifier compound.
In accordance with a third embodiment of this invention, a process is provided to recover at least one POC and at least one modifier compound from a flash process reaction mixture comprising high molecular weight P(AS), low molecular weight P(AS), cyclic and linear P(AS) oligomers, at least one POC, at least one modifier, and an alkali metal halide by-product.
The process comprises:
1) contacting the flash process reaction mixture with methanol to produce a flash process methanol-rich mixture;
2) separating the flash process methanol-rich mixture to produce a P(AS) stream and a recycle mixture;
wherein the recycle mixture comprises methanol, POC, and modifier compound.
In accordance with a fourth embodiment of this invention, a process is provided to recover at least one POC and at least one modifier compound from a flash process reaction mixture comprising high molecular weight P(AS), low molecular weight P(AS), cyclic and linear P(AS) oligomers, at least one POC, at least one modifier, and an alkali metal halide by-product.
The process comprises:
1) contacting the flash process reaction mixture with at least one POC at a temperature sufficient to dissolve a majority of the low molecular weight P(AS) and cyclic and linear oligomers to produce a flash process POC-rich mixture;
2) separating the flash process POC-rich mixture to produce a flash process solid stream and a flash process liquid stream;
wherein the flash process solid stream is in a substantially solid form and comprises insoluble P(AS), the POC, modifier compound, and alkali metal halide by-product;
wherein the flash process liquid stream is in a substantially liquid form and comprises soluble P(AS) and POC;
3) contacting the flash process solid stream with methanol to produce a flash process methanol-rich P(AS) product mixture; and
4) separating the flash process methanol-rich P(AS) product mixture to produce a high molecular weight P(AS) product and a recycle mixture;
wherein the recycle mixture comprises methanol, POC, and modifier compound.
DETAILED DESCRIPTION OF INVENTION
Different embodiments of this invention provide processes to recover at least one modifier compound and at least one POC from a P(AS) reaction mixture.
P(AS) reaction mixtures useful in this invention can be produced by any method known in the art. Examples of the reaction mixtures useful in this invention are those prepared according to U.S. Pat. Nos. 3,919,177, 4,038,261, 4,038,262, 4,116,947, 4,282,347 and 4,350,810, the entire disclosures of which are herein incorporated by reference. The U.S. Pat. No. 4,038,261 patent discloses poly(phenylene sulfide).
Generally, reaction mixtures useful in this invention are prepared by contacting a halogenated aromatic compound, at least one POC, at least one sulfur source, at least one base, and at least one modifier compound under polymerization reaction conditions to product high molecular weight P(AS). The use of modifier compounds in the production of high molecular weight P(AS) is disclosed in U.S. Pat. No. 5,334,701, herein incorporated by reference.
As used herein, the term “high molecular weight” or “high molecular weight P(AS)” means all P(AS) molecules havi
Geibel Jon F.
Vidaurri, Jr. Fernando C.
Waterman James W.
Dawson Robert
Phillips Petroleum Company
Sun Hsiang-ning
Zimmer Marc S.
LandOfFree
Menthanol extraction of polar organic compounds and modifier... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Menthanol extraction of polar organic compounds and modifier..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Menthanol extraction of polar organic compounds and modifier... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2944470