The present invention relates to a 6-hydroxy-3-hexenyl alkoxymethyl ether compound of the following general formula (1): HOCH.sub.2CH.sub.2CH=CHCH.sub.2CH.sub.2OCH.sub.2OCH.sub.2R.sup.1 (1), R.sup.1 representing a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group; and also relates to a process for preparing a 3,13-octadecadien-1-ol compound of the following formula (6): CH.sub.3(CH.sub.2).sub.3CH=CH(CH.sub.2).sub.8CH=CHCH.sub.2CH.sub.2OH (6) from the 6-hydroxy-3-hexenyl alkoxymethyl ether compound (1).

The present invention relates to a 6-hydroxy-3-hexenyl alkoxymethyl ether compound of the following general formula (1): HOCH.sub.2CH.sub.2CH=CHCH.sub.2CH.sub.2OCH.sub.2OCH.sub.2R.sup.1 (1), R.sup.1 representing a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group; and also relates to a process for preparing a 3,13-octadecadien-1-ol compound of the following formula (6): CH.sub.3(CH.sub.2).sub.3CH=CH(CH.sub.2).sub.8CH=CHCH.sub.2CH.sub.2OH (6) from the 6-hydroxy-3-hexenyl alkoxymethyl ether compound (1).

The present invention relates to a process for preparing polyoxymethylene dimethyl ethers, comprising the following steps: reaction of formaldehyde and methylal (OME.sub.1) in a reactor R1 to obtain a product mixture, distillative separation of the product mixture in a distillation unit D1 into a top stream which contains OME.sub.1, OME.sub.2, formaldehyde, methanol and water, and a bottom stream which contains OME.sub.≥3, mixing of the top stream drawn off from the distillation unit D1 with a methanol-containing stream, treatment of the mixture in a reactive distillation unit RD2 to form a top stream containing methylal and a water-containing bottom stream, introduction of the bottom stream drawn off from the distillation unit D1 into a distillation unit D3 and distillative separation of the polyoxymethylene dimethyl ethers.

The present invention relates to a process for preparing polyoxymethylene dimethyl ethers, comprising the following steps: reaction of formaldehyde and methylal (OME.sub.1) in a reactor R1 to obtain a product mixture, distillative separation of the product mixture in a distillation unit D1 into a top stream which contains OME.sub.1, OME.sub.2, formaldehyde, methanol and water, and a bottom stream which contains OME.sub.≥3, mixing of the top stream drawn off from the distillation unit D1 with a methanol-containing stream, treatment of the mixture in a reactive distillation unit RD2 to form a top stream containing methylal and a water-containing bottom stream, introduction of the bottom stream drawn off from the distillation unit D1 into a distillation unit D3 and distillative separation of the polyoxymethylene dimethyl ethers.

The present invention relates to a process for recycling polyacetal containing from 8 to 100,000 carbon atoms for the production of a produced polyoxymethylene dialkyl ether of formula R—(OCH2)n-OR′, in which R and R′ independently represent a methyl group or an ethyl group and n is an integer greater than or equal to 1, the process comprising a step of reacting an acid catalyst with a mixture comprising a polyacetal containing from 8 to 100 000 carbon atoms, a reactive polyoxymethylene dialkyl ether of formula R—(OCH2)k-OR′ in which k is an integer greater than or equal to 1, and optionally a solvent.

The present invention relates to a process for recycling polyacetal containing from 8 to 100,000 carbon atoms for the production of a produced polyoxymethylene dialkyl ether of formula R—(OCH2)n-OR′, in which R and R′ independently represent a methyl group or an ethyl group and n is an integer greater than or equal to 1, the process comprising a step of reacting an acid catalyst with a mixture comprising a polyacetal containing from 8 to 100 000 carbon atoms, a reactive polyoxymethylene dialkyl ether of formula R—(OCH2)k-OR′ in which k is an integer greater than or equal to 1, and optionally a solvent.

The present invention provides a process for preparing an alkoxymethyl alkynyl ether compound having a terminal triple bond of the following formula (4): H—C≡C(CH.sub.2).sub.aOCH.sub.2OCH.sub.2R (4), wherein R represents a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group, and “a” represents an integer of 1 to 10, the method comprising subjecting an alkynol compound having a terminal triple bond of the following formula (1): H—C≡C(CH.sub.2).sub.aOH (1), wherein “a” is as defined above, to an alkoxymethylation with a halomethyl alkyl ether compound of the following formula (3): RCH.sub.2OCH.sub.2X (3), wherein X represents a halogen atom, and R is as defined above, in the presence of a dialkylaniline compound of the following formula (2): [CH.sub.3(CH.sub.2).sub.b][CH.sub.3(CH.sub.2).sub.c]NC.sub.6H.sub.5 (2), wherein b and c represent, independently of each other, an integer of 0 to 9, to form the alkoxymethyl alkynyl ether compound (4) having a terminal triple bond.

The present invention provides a process for preparing an alkoxymethyl alkynyl ether compound having a terminal triple bond of the following formula (4): H—C≡C(CH.sub.2).sub.aOCH.sub.2OCH.sub.2R (4), wherein R represents a hydrogen atom, an n-alkyl group having 1 to 9 carbon atoms, or a phenyl group, and “a” represents an integer of 1 to 10, the method comprising subjecting an alkynol compound having a terminal triple bond of the following formula (1): H—C≡C(CH.sub.2).sub.aOH (1), wherein “a” is as defined above, to an alkoxymethylation with a halomethyl alkyl ether compound of the following formula (3): RCH.sub.2OCH.sub.2X (3), wherein X represents a halogen atom, and R is as defined above, in the presence of a dialkylaniline compound of the following formula (2): [CH.sub.3(CH.sub.2).sub.b][CH.sub.3(CH.sub.2).sub.c]NC.sub.6H.sub.5 (2), wherein b and c represent, independently of each other, an integer of 0 to 9, to form the alkoxymethyl alkynyl ether compound (4) having a terminal triple bond.

A preparation method for polyoxymethylene dimethyl ether (DMMn, generally, n=3-8 or 2-8) and mixture thereof may include one or more of the following: mixture of aqueous formaldehyde solution and polyalcohol is heated and dehydrated under vacuum conditions to yield flowing polyoxymethylene containing low moisture, which is heated and gasified to obtain relatively pure gaseous formaldehyde, which is mixed with methylal, previous batch of low-boiling-point substances applied, macromolecules, etc. in presence of catalyst. Or, the method mainly includes: aqueous formaldehyde solution, polyalcohol, and previous batch of macromolecular mixture applied are heated under vacuum conditions to remove moisture so as to obtain anhydrous flowable polyoxymethylene etherate, which is mixed with methylal, previous batch of low-boiling-point substances applied, macromolecules, etc. in presence of catalyst.

A preparation method for polyoxymethylene dimethyl ether (DMMn, generally, n=3-8 or 2-8) and mixture thereof may include one or more of the following: mixture of aqueous formaldehyde solution and polyalcohol is heated and dehydrated under vacuum conditions to yield flowing polyoxymethylene containing low moisture, which is heated and gasified to obtain relatively pure gaseous formaldehyde, which is mixed with methylal, previous batch of low-boiling-point substances applied, macromolecules, etc. in presence of catalyst. Or, the method mainly includes: aqueous formaldehyde solution, polyalcohol, and previous batch of macromolecular mixture applied are heated under vacuum conditions to remove moisture so as to obtain anhydrous flowable polyoxymethylene etherate, which is mixed with methylal, previous batch of low-boiling-point substances applied, macromolecules, etc. in presence of catalyst.