Process for the preparation of trioxane and polyoxymethylene copolymers
AssigneeTicona LLC
InventorsElke Schweers, Thomas Kaiser, Michael Haubs, Michael Rosenberg
Life of this patent
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Abstract
Processes for making trioxane, polyoxymethylene and polyoxymethylene copolymers from formaldehyde, made by the dehydrogenation of methanol in the presence of a catalytic active species set free from a sodium compound, at a temperature in the range of 300° C. to 1000° C., wherein a carrier gas stream which has a temperature above the dehydrogenation temperature is fed to the reactor.
Claims8
A process for preparing trioxane, which comprises
- converting methanol into formaldehyde by dehydrogenation in a reactor at a temperature in the range from 300 to 1000° C. in the presence of a catalyst, where a carrier gas stream having a temperature above the dehydrogenation temperature is fed to the reactor, and
- the formaldehyde prepared in this way is trimerized to give trioxane.
A process for preparing polyoxymethylene, which comprises
- converting methanol into formaldehyde by dehydrogenation in a reactor at a temperature in the range from 300 to 1000° C. in the presence of a catalyst, where a carrier gas stream having a temperature above the dehydrogenation temperature is fed to the reactor, and
- optionally, purifying the formaldehyde obtained in this way,
- polymerizing the formaldehyde,
- capping the end groups of the polymer prepared in this way and
- optionally, homogenizing the polymer in the melt and/or providing it with suitable additives.
A process for preparing polyoxymethylene copolymers, which comprises
- converting methanol into formaldehyde by dehydrogenation in a reactor at a temperature in the range from 300 to 1000° C. in the presence of a catalyst, where a carrier gas stream having a temperature above the dehydrogenation temperature is fed to the reactor, and
- trimerizing the formaldehyde obtained in this way to give trioxane,
- optionally, purifying the trioxane,
- copolymerizing the trioxane with cyclic ethers or cyclic acetals,
- optionally, removing unstable end groups and
- optionally, homogenizing the polymer prepared in this way in the melt and/or admixing it with suitable additives.
A process for preparing polyoxymethylene copolymers, which comprises
- converting methanol into formaldehyde by dehydrogenation in a reactor in the presence of a catalyst at a temperature in the range from 300 to 1000° C., where a circulating gas stream comprising by-products of the dehydrogenation is passed through the reactor, and
- optionally, purifying the formaldehyde obtained in this way,
- copolymerizing the formaldehyde with cyclic others or cyclic acetals,
- optionally, removing unstable end groups and
- optionally, homogenizing the polymer prepared in this way in the melt and/or admixing it with suitable additives.
Process for preparing trioxane, which comprises converting methanol into formaldehyde by preparing formaldehyde from methanol by dehydrogenation of the methanol at a temperature in the range from 300 to 1000° C. in the presence of a catalytically active species set free from a sodium compound, wherein the sodium compound used is
- a) sodium alkoxides,
- b) sodium carboxylates,
- c) sodium salts of C—H acid compounds or
- d) sodium oxide, sodium hydroxide, sodium nitrite, sodium acetylide, sodium carbide, sodium hydride or sodium carbonyl, and
- trimerizing the formaldehyde prepared to give trioxane.
A process for preparing polyoxymethylene, which comprises converting methanol into formaldehyde by preparing formaldehyde from methanol by dehydrogenation of the methanol at a temperature in the range from 300 to 1000° C. in the presence of a catalytically active species set free from a sodium compound, wherein the sodium compound used is
- a) sodium alkoxides,
- b) sodium carboxylates,
- c) sodium salts of C—H acid compounds or
- d) sodium oxide, sodium hydroxide, sodium nitrite, sodium acetylide, sodium carbide, sodium hydride or sodium carbonyl, and
- optionally purifying the formaldehyde
- polymerizing the formaldehyde,
- capping the end groups of the polymer and
- optionally homogenizing the polymer in the melt and/or providing it with additives.
A process for preparing polyoxymethylene copolymers, which comprises converting methanol into formaldehyde by preparing formaldehyde from methanol by dehydrogenation of the methanol at a temperature in the range from 300 to 1000° C. in the presence of a catalytically active species set free from a sodium compound, wherein the sodium compound used is
- a) sodium alkoxides,
- b) sodium carboxylates,
- c) sodium salts of C—H acid compounds or
- d) sodium oxide, sodium hydroxide, sodium nitrite, sodium acetylide, sodium carbide, sodium hydride or sodium carbonyl, and
- trimerizing the formaldehyde obtained in this way to give trioxane, optionally purifying the trioxane,
- copolymerizing the trioxane with cyclic ethers or cyclic acetals,
- optionally removing unstable end groups and
- optionally homogenizing the polymer in the melt and/or admixing it with additives.
A process for preparing polyoxymethylene copolymers, which comprises converting methanol into formaldehyde by preparing formaldehyde from methanol by dehydrogenation of the methanol at a temperature in the range from 300 to 1000° C. in the presence of a catalytically active species set free from a sodium compound, wherein the sodium compound used is
- a) sodium alkoxides,
- b) sodium carboxylates,
- c) sodium salts of C—H acid compounds or
- d) sodium oxide, sodium hydroxide, sodium nitrite, sodium acetylide, sodium carbide, sodium hydride or sodium carbonyl, and
- optionally purifying the formaldehyde,
- copolymerizing the formaldehyde with cyclic ethers or cyclic acetals,
- optionally removing unstable end groups and
- homogenizing the polymer in the melt and/or admixing it with additives.
Dependencies are inferred from the claim text.