Ticona Gmbh

Hoechst Aktiengesellschaft

Other

Celanese Sales Germany Gmbh

Michael Hoffmockel

Michael Haubs

Jürgen Lingnau

Karl-Friedrich Muck

Gunter Sextro

Robert M Gronner

Karl-Friedrich Mück

Horst Roeschert

Gerhard Emig

Horst Röschert

Frank Kern

Arnold Schneller

Klaus Kurz

Joachim Clauss

Michael G Yearwood

Gerhard Reuschel

Matthias Göring

Peter Eckardt

Benno Kruger

Karlheinz Burg

Juergen Lingnau

Dietrich Fleischer

Lowell Jay Larson

Helmut Schlaf

Damian Feord

Stefan Disch

Satyajit Verma

Ernst Hofmann

Karl-Friedrich M&uuml;ck

Karl-Friedrich M Uck

Jeurgen Lingnau

Karl-Friedrich Mueck

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

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

The present invention relates to a process for the preparation of oxymethylene polymers as well as oxymethylene polymers obtainable therefrom. The process includes polymerization of a monomer, which forms &#x2014;CH&#x2014;O&#x2014; units in the presence of an acetal of formaldehyde or a polyhydric alcohol and an initiator for cationic polymerization. The initiator may be a heteropoly acid or an acid salt thereof which is dissolved in an alkyl ester of a polybasic carboxylic acid.

Oxymethylene polymers and process for the preparation thereof

An initiator for cationic polymerization comprises a salt of a protic acid as well as a protic acid. 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.

Oxymethylene copolymers having a high proportion of terminal alkyl ether groups and having terminal hydroxyalkylene groups are described. These polymers are distinguished by high thermal stability and high hot water resistance. Furthermore, a process for the preparation of oxymethylene copolymers is described in which the polymerization of at least one monomer forming &#x2014;CH&#x2014;O&#x2014; units is effected in the presence of at least one acetal of formaldehyde and of at least one initiator of cationic polymerization and the initiator of cationic polymerization is used in an amount of less than or equal to 10mol %, based on the amount of the monomers present at the beginning of the polymerization and forming &#x2014;CH&#x2014;O&#x2014; units, in which starting materials of the polymerization are used such that the content of water and formic acid at the beginning of the polymerization is less than or equal to 40 ppm, and in which the initiator and/or the active polymer chains are deactivated by treatment of the prepared polymer with a base-containing protic solvent.

Oxymethylene copolymers and the use thereof and process for the preparation of oxymethylene copolymers

A process and an apparatus are described for preparation of oxymethylene polymers. This process encompasses polymerization, in a homogeneous phase, of a monomer which forms oxymethylene groups, as far as 90% of maximum conversion in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, followed by deactivation of the reaction mixture. The resultant oxymethylene polymers have alkyl ether end groups and are extremely stable.

Process for preparation of oxymethylene polymers in a homogeneous phase, and use

The invention relates to a process for preparation of polymer blends comprising at least one polyoxymethylene and at least one thermoplastic elastomer, where the thermoplastic elastomer is micropelletized by a pelletizing process and the pellets obtained in a) are dispersed in the polyoxymethylene matrix via melting of the components and mixing of these at low shear forces, and also to the use of micropelletized thermoplastic elastomers for preparation of polyoxymethylenes with low formaldehyde emission.

Process for preparation of polymer blends composed of polyoxymethylenes and of thermoplastic elastomers

A process is described for preparation of oxymethylene homo- and copolymers. This encompasses heterogeneous polymerization of a monomer which forms oxymethylene groups in the presence of an acetal of formaldehyde and of an initiator for cationic polymerization, followed by the deactivation of the polymer in a homogeneous phase via treatment with a basic aprotic solvent or with an aprotic solvent which comprises a base. Oxymethylene homopolymers with very high stability are also described.

Process for preparation of oxymethylene polymers, selected polymers, and their use

A process for preparing acetals from aldehydes and alcohols is carried out by generating a reaction/distillation zone charged with an acidic fixed bed catalyst in a distillation column, feeding the aldehyde and the alcohol to the reaction/distillatlon zone and at least partly converting them to the acetal, heating the column bottom disposed below the reaction/distillation zone in order to at least partly evaporate the bottom's mixture and to establish a defined temperature in the reaction/distillation zone, feeding an extractant into a rectifying section of the column, disposed above the reaction/distillation zone and condensing a product having more than 90% by weight of acetal at the top of the column.

Processes for the manufacture of acetals

Process for removing methanol from formaldehyde-containing solutions. The present invention relates to a process for removing methanol from formaldehyde-containing solutions, with methanol being converted into formaldehyde dimethyl acetal by reactive distillation in the presence of an acidic fixed-bed catalyst, and the resultant mixture comprising methanol, formaldehyde dimethyl acetal and possibly other impurities being distilled off.

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Niedernhausen, Germany

Michael Hoffmockel