PROCESS FOR ETHYNYLATING SPECIFIC ALPHA, BETA-UNSATURATED KETONES

Abstract

The present invention relates to an improved process for ethynylating specific ,-unsaturated ketones for producing tertiary acetylenic alcohols.

Claims

1. Process for the production of compounds of formula (I) ##STR00024## wherein R is H; a linear, branched or cyclic C.sub.1-C.sub.30 alkyl group, which can comprise ring systems and, which can be substituted with oxygen atoms; or a linear, branched or cyclic C.sub.2-C.sub.30 alkylene moiety, which can comprise ring systems and, which can be substituted with oxygen atoms, wherein a first step lithium is added to NH.sub.3 and then ethyne (HCCH) is added to the reaction mixture and in a second step (step (II)) a compound of formula (II) ##STR00025## wherein R and the wavy bond have the same meaning as defined for the compound of formula (I), and then in a third step (step (III)) the obtained product is hydrolyzed, wherein the steps (I) and step (II) and optionally step (III) are controlled by monitoring the reaction progress by using Raman spectroscopy.

2. Process according to claim 1, wherein R is H; a linear, branched or cyclic C.sub.1-C.sub.15 alkyl group, which can comprise ring systems and, which can be substituted with oxygen atoms; or a linear, branched or cyclic C.sub.1-C.sub.15 alkenyl group, which can comprise ring systems and, which can be substituted with oxygen atoms.

3. Process according to claim 1, wherein R is H; a linear or branched C.sub.1-C.sub.10 alkyl group; a linear, branched or cyclic C.sub.1-C.sub.15 alkenyl group, which comprise one carbon-carbon double bond; or a substituted cyclohexene ring chosen from the group consisting of ##STR00026## wherein the * shows the C bonding to the formula (I) and (II) and R is H or a C.sub.1-C.sub.4 alkyl group or (CO)C.sub.1-C.sub.4alkyl or C(COCH.sub.3)(CH.sub.3).sub.2.

4. Process according to claim 1, wherein R is H; a linear or branched C.sub.1-C.sub.10 alkyl group; a linear, branched or cyclic C.sub.1-C.sub.15 alkenyl group, which comprise one carbon-carbon double bond; or a substituted cyclohexene ring chosen from the group consisting of ##STR00027## wherein the * shows the C bonding to the formula (I) and (II).

5. Process according to claim 1, wherein R is H.

6. Process according to claim 1, wherein step (I) is carried out at a temperature range of from 90 C. to 10 C.

7. Process according to claim 1, wherein the dosing of acetylene is stopped when new peaks in the region of 1880-1835 cm.sup.1 appear.

8. Process according to claim 1, wherein at least one inert solvent is added to the reaction mixture when two peaks in the region of 1880-1835 cm.sup.1 are observed.

9. Process according to claim 8, wherein the at least one inert solvent is chosen from the group consisting of ethers and aromatic hydrocarbon compounds.

10. Process according to claim 8, wherein the at least one inert solvent is chosen from the group consisting of diethyl ether, di-n-propyl ether, diisopropyl ether, dioxane, tetrahydrofuran, 2-methyl tetrahydrofuran, benzene and toluene.

11. Process according to claim 1, wherein the dosing of acetylene is stopped when two peaks in the region of 1880-1835 cm.sup.1 have disappeared and the peak approximately at 1885 cm.sup.1 appears.

12. Process according to claim 1, wherein the dosing of the compound of formula (II) ##STR00028## wherein R is H; a linear, branched or cyclic C.sub.1-C.sub.30 alkyl group, which can comprise ring systems and, which can be substituted with oxygen atoms; or a linear, branched or cyclic C.sub.2-C.sub.30 alkylene moiety, which can comprise ring systems and, which can be substituted with oxygen atoms is stopped when the band approximately at 1885 cm.sup.1 has disappeared.

13. Process according to claim 1, wherein step (II) is carried out at a temperature between 70 C. and 0 C.

14. Process according to claim 1, wherein step (III) is carried out at a temperature between 70 C. and 0 C.

15. Process according to claim 1, wherein step (III) the at least compound is chosen from the group consisting of sulfuric acid, acetic acid, water and ammonium chloride.

Description

[0110] At the end of step (III), the compound of formula (I) is obtained and isolated and purified by using commonly known methods.

[0111] FIG. 1: Raman spectrum of ammonia

[0112] FIG. 2: Raman spectrum of ammonia after addition of some of the lithium

[0113] FIG. 3: Raman spectrum of acetylene solvated in ammonia

[0114] FIG. 4: Raman spectrum of lithium carbide

[0115] FIG. 5: Raman spectrum of lithium acetylide

[0116] FIG. 6: Raman spectrum of the lithium alkoxide product III.

[0117] FIG. 7: Raman spectra of the reactions Example 1 and Comparison Example 1 (C1)

[0118] The following examples illustrate the invention further without limiting it. All percentages and parts, which are given, are related to the weight and the temperatures are given in C., and the pressures are absolute pressures when not otherwise stated.

EXAMPLES

Example 1

[0119] Ammonia gas is condensed into a cooled (50 to 30 C.) 2L jacketed vessel fitted with a Raman probe under argon until the vessel contains approximately 500 ml of liquid ammonia. Lithium metal (10.5 g) is slowly added with stirring (FIG. 1.fwdarw.FIG. 2). Acetylene gas is added to the reaction mixture at a rate of approximately 1 L/min (FIG. 3). The addition of acetylene is stopped when the Raman spectrum indicated formation of the lithium carbide (FIG. 4).

[0120] The reaction temperature is increased to between 10 and +10 C. and diethyl ether (approximately 625 ml) is added. The reaction mixture is cooled to 15 to 5 C. and acetylene gas is added at a rate of approximately 1 L/min. When complete formation of the lithium acetylide is observed (FIG. 5), a solution of methyl vinyl ketone (120 g in 120 ml of diethyl ether) is prepared and is added to the lithium acetylide solution at approximately 3.3 ml/min. The reaction is monitored by Raman spectroscopy and as soon as the consumption of the lithium acetylide is complete (FIG. 6), the addition is stopped and the unused methyl vinyl ketone solution is disposed of (approx. 171 g of MVK solution added). The reaction mixture is stirred and then added over approximately 20 minutes to a cooled solution of sulfuric acid (30%, approximately 400 ml).

[0121] The ether layer is separated, dried over sodium sulfate and most of the ether is removed at normal pressure to give the crude 3-methylpent-1-en-4-yn-3-ol as a yellow oil (248.5 g, 53.3 weight % content, 97.9% yield based on MVK and 91.3% yield based on lithium).

Comparative Example 1 (C.SUB.1.) (not Using a Raman Spectroscopy to Monitor the Reaction Progress)

[0122] The procedure of Example 1 was repeated, without the use of Raman spectroscopy using the same amounts of lithium metal and methyl vinyl ketone solution. The point at which the lithium acetylide was fully consumed was estimated to be reached after the addition of approximately 193 g of the MVK solution (approx. 1.59 mol).

[0123] After work-up, 255.8 g of crude 3-methylpent-1-en-4-yn-3-ol was obtained as a yellow oil (51.5 weight % content, 86.6% yield based on MVK). In addition, a polymer was formed (see FIG. 7) that made the removal of the mixture from the reactor and purification significantly harder.

Comparative Example 2 (C.SUB.2.) (not Using a Raman Spectroscopy to Monitor the Reaction Progress)

[0124] The procedure of Example 1 was repeated, without the use of Raman spectroscopy using the same amounts of lithium metal and methyl vinyl ketone solution. The point at which the lithium acetylide was fully consumed was estimated to be reached after the addition of approximately 146 g of the MVK solution (approx. 1.20 mol).

[0125] After work-up, 209.8 g of crude 3-methylpent-1-en-4-yn-3-ol was obtained as a yellow oil (52.9 weight % content, 96.3% yield based on MVK and 76.5% yield based on lithium).