Ticona Gmbh

Hoechst Aktiengesellschaft

Hoechst Celanese Corporation

Celanese Sales Germany Gmbh

Hoechst Aktiengelesellschaft

Michael Haubs

Jürgen Lingnau

Michael Hoffmockel

Reinhard Wagener

Damian Feord

Klaus Kurz

Hendrich A Chiong

Jacob Grayson

Robert M Gronner

Horst Röschert

Venkata Nekkanti

Arnold Schneller

Horst Roeschert

Thomas Kaiser

Elke Schweers

Michael Rosenberg

Stanley Leonard

Willi Kreuder

Joachim Clauss

Juergen Wildhardt

Claus-Peter Krieg

Mark Shatzer

Helmut Bahrmann

Andreas Schleicher

Helmut Scheckenbach

Thomas Muller

Werner Prass

Detlef H Skaletz

Harald Cherdron

Axel Schonfeld

Paul Foley

Lowell Jay Larson

Marie Borzo

Dominick L Cangiano

Stefan Disch

Friedrich Herold

Michael G Yearwood

Doris Pospiech

Otto Hermann-Schonherr

Frank Bohme

Hansotto Drotloff

Joni Sianturi

Stephan Wagner

Olaf Besser

Dennis Kappler

Eberhard Mann

Wildhardt Juergen

Thorsten Niklas

Stanislaw Penczek

Afif Nesheiwat

Markus Lehrl

Jeurgen Lingnau

Sianturi Joni

Methods of forming a polyarylene sulfide and systems as may be utilized in carrying out the methods are described. Included in the formation method is a filtration process for treatment of a mixture, the mixture including a polyarylene sulfide, a salt byproduct of the polyarylene sulfide formation reaction, and a solvent. The filtration process includes maintaining the downstream side of the filter medium at an increased pressure. The downstream pressure can such that the boiling temperature of the mixture at the downstream pressure can be higher than the temperature at which the polyarylene sulfide is insoluble in the solvent.

Salt byproduct separation during formation of polyarylene sulfide

A method for formation of a semi-crystalline polyarylene sulfide is described. The method can include reaction of sulfur-containing monomer with a dihaloaromatic monomer in an organic amide solvent to form a polymer following by combination of the polymer with a crystallization solution. The crystallization solution is pre-heated and the mixture formed is slowly cooled to crystallize the polymer.

Method of polyarylene sulfide crystallization

Methods, devices, and systems that can be utilized in separating a polymer from other compounds of a polymer formation process are described. The methods utilize multiple sedimentors in a countercurrent flow design in conjunction with different solvent solutions in the multiple sedimentors to separate a product polymer from other compounds of a polymer formation process. The sedimentors include feed inlets that can encourage contact between countercurrent flows and improve mass transfer rates between the countercurrent flows.

Method and system for separation of a polymer from multiple compounds

The present invention relates to a process for producing cyclic acetal comprising i) preparing a liquid reaction mixture comprising a) formaldehyde source, b) an aprotic compound and c) a catalyst; and ii) converting the formaldehyde source into cyclic acetals.

Process for the production of trioxane

A multi-stage process and system for formation of a polyarylene sulfide is described. The multi-stage process can include at least three separate formation stages that can take place in three different reactors. The first stage of the formation process can include reaction of an alkali metal sulfide with an organic amide solvent to form a complex including a hydrolysis product of the solvent and an alkali metal hydrogen sulfide. The second stage of the formation process can include reaction of the complex formed in the first stage with a dihaloaromatic monomer to form a prepolymer, and the third stage can include further polymerization of the prepolymer with additional monomers to form the final product.

Multi-stage process for forming polyarylene sulfides

The present invention relates to a process for producing cyclic acetal comprising i) preparing a reaction mixture comprising a) a formaldehyde source in a liquid medium and b) a catalyst; ii) converting the formaldehyde source into cyclic acetals, wherein the final conversion of said formaldehyde source to said cyclic acetal is greater than 10% on basis of the initial formaldehyde source.

Process for producing a cyclic acetal

The present invention relates to a process for producing cyclic acetal comprising i) preparing a liquid reaction mixture comprising a) a formaldehyde source, b) an aprotic compound and c) a catalyst; wherein the total amount of protic compounds is less than 40 wt.-%, based on the total weight of the reaction mixture; and ii) converting the formaldehyde source into cyclic acetals.

Process for the production of trioxane from aqueous formaldehyde sources

A process for producing a cyclic acetal is disclosed. According to the process, a formaldehyde source is combined with an aprotic compound and contacted with a heterogeneous catalyst which causes the formaldehyde source to convert into a cyclic acetal such as trioxane. The catalyst, for instance, may comprise a solid catalyst such as an ion exchange resin. In one embodiment, the process is used for converting anhydrous formaldehyde gas to trioxane. The anhydrous formaldehyde gas may be produced form an aqueous formaldehyde solution by an extractive distillation.

Process for producing a cyclic acetal in a heterogeneous reaction system

A process for producing cyclic acetals is described. A formaldehyde source is contacted with an aprotic compound in the presence of a catalyst to produce the cyclic acetals. The aprotic compound can increase conversion rates and/or efficiency. In one embodiment, the formaldehyde source is obtained from methanol. In particular, methanol can be converted into formaldehyde which is then converted into a cyclic acetal. In one embodiment, the cyclic acetal can then be used to produce oxymethylene polymers.

Integrated process for producing cyclic acetals and oxymethylene polymers

A process for recycling polyoxymethylene polymers is disclosed. A polyoxymethylene polymer is at least partially dissolved in an aprotic compound. The resulting solution or suspension (liquid mixture) is then contacted with a catalyst which causes the polyoxymethylene polymer to be converted into a cyclic acetal. The cyclic acetal can be separated, collected and used in other processes. In one embodiment, the cyclic acetal may be used to produce a polyoxymethylene polymer.

Process for recycling polyacetals

An initiator for cationic polymerization comprises a salt of a protic acid as well as a protic add. The molar ratio of protic acid to salt is in the range from 1:0.01 to 1:2000. The initiator is used for example for cationic homo- or copolymerization of trioxane, and permits stable and flexible operation of the polymerization.

Initiator

The present invention relates to a process for the preparation of oxymethylene polymers, the oxymethylene polymers obtained therefrom as well as their use.

Process for producing oxymethylene polymers

Oxymethylene polymers having a bimodal distribution or having a distribution of higher modality and having a targeted content of a low molecular weight fraction of from 1 to 5 percent by mass are described. Moldings of these polymers are distinguished by high low-temperature notched impact strength associated with a high modulus of elasticity.

Oxymethylene polymers, process for the preparation thereof and use thereof

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Bad Kreuznach, Germany

Michael Haubs