Process for preparing an acetal from an olefin using PtI2 or PtBr2

Abstract

Process for preparing an acetal from an olefin using PtI.sub.2 or PtBr.sub.2.

Claims

1. Process comprising the process steps of: a) initially charging an olefin; b) adding a compound of formula (I): ##STR00011## where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 are selected from: H, (C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl; and, if R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8 are (C.sub.6-C.sub.20)-aryl, the aryl ring may have substituents selected from: (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl; c) adding PtI.sub.2 or PtBr.sub.2; d) adding an alcohol selected from: methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, ethane-1,2-diol, propane-1,2-diol, propane-1,3-diol, butane-1,4-diol; e) feeding in CO and H.sub.2; f) heating the reaction mixture from steps a) to e), to convert the olefin to an acetal.

2. Process according to claim 1, where R.sup.2, R.sup.3, R.sup.5, R.sup.6, R.sup.7, R.sup.8 are selected from: (C.sub.1-C.sub.12)-alkyl, (C.sub.6-C.sub.20)-aryl.

3. Process according to claim 1, where R.sup.5, R.sup.6, R.sup.7, R.sup.8 are (C.sub.6-C.sub.20)-aryl.

4. Process according to claim 1, where R.sup.2 and R.sup.3 are (C.sub.1-C.sub.12)-alkyl.

5. Process according to claim 1, where R.sup.1 and R.sup.4 are H.

6. Process according to claim 1, wherein the compound (I) has the structure (1): ##STR00012##

7. Process according to claim 1, wherein PtI.sub.2 is added in process step c).

8. Process according to claim 1, wherein PtBr.sub.2 is added in process step c).

9. Process according to claim 1, wherein the alcohol in process step d) is selected from: methanol, ethanol, 1-propanol, 1-butanol, ethane-1,2-diol, propane-1,2-diol.

10. Process according to claim 1, wherein the alcohol in process step e) is MeOH.

11. Process according to claim 1, wherein CO and H.sub.2 are fed in at a pressure in a range from 1 MPa (10 bar) to 6 MPa (60 bar).

12. Process according to claim 1, wherein CO and H.sub.2 are fed in at a pressure in a range from 3 MPa (30 bar) to 5 MPa (50 bar).

13. Process according to claim 1, wherein the olefin is selected from: ethene, propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene, 1,2-butadiene, 1-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene, heptene, 1-octene, 2-octene, di-n-butene, tri-n-butene, 1,7-octadiene, 1,9-decadiene, methyl 9-decenoate (9-Dame) or mixtures thereof.

14. Process according to claim 1, wherein the olefin has two double bonds.

15. Process according to claim 1, wherein the olefin has two double terminal bonds.

Description

GENERAL EXPERIMENTAL DESCRIPTION

[0039] The olefin, an inert solvent, the alcohol, PtX.sub.2 (X=halogen) and the ligand are placed in a stainless steel autoclave from Parr Instruments under argon. Synthesis gas CO/H.sub.2 (1:1) is injected and the reaction is conducted at the chosen reaction temperature while stirring. After the end of the reaction time, the autoclave is cooled down to room temperature, the residual pressure is released, and a GC sample for determination of the yield of target product is taken and analysed.

Variation of the Olefin: 1-Octene

Reaction Conditions:

[0040] 10 mmol 1-octene, 0.5 mol % PtI.sub.2, 2.2 eq. Xantphos (1), solvent: toluene, p(CO/H.sub.2): 40 bar, T: 80? C., t: 24 h.

[0041] Monoalcohol: 4 equivalents: diol: 2 equivalents

TABLE-US-00001 Acetal Yield [%] [00003] 90 [00004] 48 [00005] 75 [00006] 81

Variation of the Alcohol: 1,3-Butadiene

Reaction Conditions:

[0042] 10 mmol 1,3-butadiene, 0.5 mol % PtI.sub.2, 2.2 eq. Xantphos (1), solvent: toluene, p (CO/H.sub.2): 40 bar, T: 80? C., t: 24 h.

[0043] Monoalcohol: 4 equivalents: diol: 2 equivalents

TABLE-US-00002 Yield Acetal [%] [00007] 55 [00008] 86 [00009] 50

Variation of the Halogen

[0044] ##STR00010##

[0045] 10 mmol of 1-octene, 40 mmol of methanol, 10 ml of toluene, PtX.sub.2 (0.1 mol %), Xantphos (1) (0.22 mol %) are introduced into a 25 ml autoclave under argon. Synthesis gas (CO/H.sub.2=1.1) is injected to 40 bar. The reaction is conducted at 120? C. while stirring and while measuring the gas consumption in the autoclave (electronic pressure transducer, Specview software) for 24 h. The autoclave is cooled down to room temperature and the pressure is released. The yield is determined by taking a GC sample.

[0046] The reaction is conducted for X=I/Br/Cl.

Reaction Conditions:

[0047] 10 mmol 1-octene, 0.1 mol % PtX.sub.2, 2.2 eq. Xantphos (1), solvent: toluene, p (CO/H.sub.2): 40 bar, T: 120?? C., t: 24 h.

Yields:

[0048] PtI.sub.2: 46%

[0049] PtBr.sub.2: 36%

[0050] PtCl.sub.2*: 7%

[0051] * noninventive comparative experiment

[0052] As shown by the experimental results, the object is achieved by the process according to the invention.