The present invention relates to an improved process for preparing hydrazine hydrate from the azine of methyl ethyl ketone obtained from methyl ethyl ketone by oxidizing ammonia with hydrogen peroxide in the presence of an activator, characterized in that it comprises a step of recycling the pyrazoline-class heterocycles purge.

The present invention relates to an improved process for preparing hydrazine hydrate from the azine of methyl ethyl ketone obtained from methyl ethyl ketone by oxidizing ammonia with hydrogen peroxide in the presence of an activator, characterized in that it comprises a step of recycling the pyrazoline-class heterocycles purge.

The present invention provides a process for preparing (9Z,11E)-9,11-hexadecadienal of the following formula (4), the process comprising: subjecting (2E)-2-heptenal of the following formula (1) to a Wittig reaction with a triarylphosphonium 9,9-dialkoxynonylide compound of the following general formula (2), wherein Ar represents an aryl group that may be same with or different from each other, and R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, or R.sup.1 and R.sup.2 may form together a divalent hydrocarbon group, R.sup.1-R.sup.2, having 2 to 10 carbon atoms to form a (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound of the following general formula (3), wherein R.sup.1 and R.sup.2 are as defined above; and hydrolyzing the (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound (3) to form (9Z,11E)-9,11-hexadecadienal (4).

##STR00001##

The present invention provides a process for preparing (9Z,11E)-9,11-hexadecadienal of the following formula (4), the process comprising: subjecting (2E)-2-heptenal of the following formula (1) to a Wittig reaction with a triarylphosphonium 9,9-dialkoxynonylide compound of the following general formula (2), wherein Ar represents an aryl group that may be same with or different from each other, and R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, or R.sup.1 and R.sup.2 may form together a divalent hydrocarbon group, R.sup.1-R.sup.2, having 2 to 10 carbon atoms to form a (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound of the following general formula (3), wherein R.sup.1 and R.sup.2 are as defined above; and hydrolyzing the (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound (3) to form (9Z,11E)-9,11-hexadecadienal (4).

##STR00001##

The present invention provides a process for preparing (9Z,11E)-9,11-hexadecadienal of the following formula (4), the process comprising: subjecting (2E)-2-heptenal of the following formula (1) to a Wittig reaction with a triarylphosphonium 9,9-dialkoxynonylide compound of the following general formula (2), wherein Ar represents an aryl group that may be same with or different from each other, and R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, or R.sup.1 and R.sup.2 may form together a divalent hydrocarbon group, R.sup.1—R.sup.2, having 2 to 10 carbon atoms to form a (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound of the following general formula (3), wherein R.sup.1 and R.sup.2 are as defined above; and hydrolyzing the (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound (3) to form (9Z,11E)-9,11-hexadecadienal (4). ##STR00001##

The present invention provides a process for preparing (9Z,11E)-9,11-hexadecadienal of the following formula (4), the process comprising: subjecting (2E)-2-heptenal of the following formula (1) to a Wittig reaction with a triarylphosphonium 9,9-dialkoxynonylide compound of the following general formula (2), wherein Ar represents an aryl group that may be same with or different from each other, and R.sup.1 and R.sup.2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 15 carbon atoms, or R.sup.1 and R.sup.2 may form together a divalent hydrocarbon group, R.sup.1—R.sup.2, having 2 to 10 carbon atoms to form a (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound of the following general formula (3), wherein R.sup.1 and R.sup.2 are as defined above; and hydrolyzing the (5E,7Z)-16,16-dialkoxy-5,7-hexadecadiene compound (3) to form (9Z,11E)-9,11-hexadecadienal (4). ##STR00001##

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 primarily relates to compounds of formula (I) as defined herein and to compositions comprising one, two, three or more compounds of formula (I) as defined herein, or consisting of two, three or more compounds of formula (I) as defined herein. The invention further relates to methods for producing compounds of formula (I) (or (Ia) or (Ib)), to the use of compounds of formula (I) as fragrance substances and the use of compositions comprising a compound of formula (I) or consisting of compounds of formula (I) as fragrance substance mixtures. It further relates to fragrance substance compositions comprising or consisting of compounds or compositions as defined herein and one or more additional fragrance substances, to perfumed products comprising compounds or compositions or fragrance substance compositions as defined herein, to methods for producing perfumed products as defined herein and to methods for perfuming hair, skin, textile fibres, surfaces and/or ambient air.

The present invention primarily relates to compounds of formula (I) as defined herein and to compositions comprising one, two, three or more compounds of formula (I) as defined herein, or consisting of two, three or more compounds of formula (I) as defined herein. The invention further relates to methods for producing compounds of formula (I) (or (Ia) or (Ib)), to the use of compounds of formula (I) as fragrance substances and the use of compositions comprising a compound of formula (I) or consisting of compounds of formula (I) as fragrance substance mixtures. It further relates to fragrance substance compositions comprising or consisting of compounds or compositions as defined herein and one or more additional fragrance substances, to perfumed products comprising compounds or compositions or fragrance substance compositions as defined herein, to methods for producing perfumed products as defined herein and to methods for perfuming hair, skin, textile fibres, surfaces and/or ambient air.