PURIFICATION OF AN ETHYLENICALLY UNSATURATED ALCOHOL STREAM, PREPARATION OF AN ETHYLENICALLY UNSATURATED ALDEHYDE, IN PARTICULAR PRENAL, AND COMPOUNDS DERIVED THEREFROM

Abstract

Organically bound nitrogen is removed from an ethylenically unsaturated alcohol stream by contacting the alcohol stream with a weakly acidic solid adsorbent. Trace amounts of organically bound nitrogen tend to poison the oxidation catalyst in subsequent oxidation processes using the ethylenically unsaturated alcohol stream.

Claims

1.-18. (canceled)

19. A process for removing organically bound nitrogen from an ethylenically unsaturated alcohol stream, by contacting the alcohol stream with a weakly acidic solid adsorbent.

20. The process of claim 19, wherein the solid adsorbent is a crosslinked resin having phosphonic functional groups.

21. The process of claim 19, wherein the solid adsorbent is a silica-alumina hydrate.

22. The process of claim 19, wherein the ethylenically unsaturated alcohol stream is passed over a bed of the weakly acidic solid adsorbent.

23. The process of claim 19, wherein the ethylenically unsaturated alcohol stream comprises, after contacting the alcohol stream with a weakly acidic solid adsorbent, less than 2 ppm of organically bound nitrogen.

24. A process for the preparation of an ethylenically unsaturated aldehyde from an ethylenically unsaturated alcohol in the presence of an oxidant and a catalytically active metal catalyst, wherein prior to contacting with the catalytically active metal catalyst, the ethylenically unsaturated alcohol stream is treated by a process according to claim 19.

25. The process according to claim 24, wherein the catalytically active metal is selected from platinum, palladium and gold.

26. The process according to claim 24, wherein the catalytically active metal is deposited on a support.

27. The process according to claim 26, wherein the support is selected from carbonaceous materials and oxidic materials.

28. The process according to claim 24, wherein the oxidant is selected from oxygen and hydrogen peroxide.

29. The process according to claim 24, the process being carried out at a temperature in the range of from 1 to 250 C.

30. The process according to claim 19, wherein the reaction is performed in the presence of a liquid phase, which contains at least 25 wt.-% of water.

31. The process according to claim 30, wherein the liquid phase contains 1 to 75 wt.-% of the ethylenically unsaturated alcohol, based on the total amount of the liquid phase.

32. The process according to claim 24, wherein the ethylenically unsaturated alcohol is 3-methylbut-2-en-1-ol (prenol) and the ethylenically unsaturated aldehyde is 3-methylbut-2-en-1-al (prenal).

33. The process according to claim 32, wherein prenol is obtained by reacting a formaldehyde source and isobutylene to obtain 3-methylbut-3-en-1-ol (isoprenol), and subjecting at least part of the obtained isoprenol to isomerization.

34. A process for the preparation of 3,7-dimethyl-octa-2,6-dienal (citral) comprising: obtaining prenal by the process according to claim 32: condensing the prenal with prenol to obtain diprenyl acetal of prenal; and subjecting the diprenyl acetal of prenal to cleaving conditions to obtain citral via prenyl (3-methyl-butadienyl) ether and 2,4,4-trimethyl-3-formyl-1,5-hexadiene.

35. A process for the preparation of menthol, comprising preparing citral by the process according to claim 34, and reacting citral to obtain menthol.

36. A process for the preparation of linalool, comprising preparing citral by the process according to claim 34, and reacting citral to obtain linalool.

Description

[0142] The present invention can be further explained and illustrated on the basis of the following figures and examples. However, it will be understood that these figures and examples are included merely for purposes of illustration and are not intended to limit the scope of the invention in any way.

[0143] FIG. 1 shows the oxygen consumption in the liquid phase oxidation of prenol.

[0144] FIG. 2 shows the conversion and selectivity of the oxidation of prenol to prenal. Examples

EXAMPLE 1REMOVAL OF UROTROPIN FROM A PRENOL STREAM USING DIFFERENT ADSORBENTS

[0145] Different adsorbents are tested for their ability to remove urotropin from prenol. For this purpose, the relevant adsorbent is mixed with water at ambient temperature and stirred for 15 min for washing. Subsequently, the water-wet adsorbent is stirred with small amounts of the prenol (nitrogen-free) for 5 min. The prenol-wet adsorbent is then transferred to a column and the untreated prenol feed is run through the column (top down). The results are shown in table 1.

TABLE-US-00001 TABLE 1 Removal of urotropin from a prenol stream using different adsorbents urotropin urotropin before adsorption after adsorption # adsorbent [ppm] [ppm] 1* Lewatit CNP80 .sup.[1] 35-51 11 2* Purolite C104 13 DL Plus .sup.[2] 3* Purolite C107 .sup.[3] 14 4* BASF F-24X .sup.[4] 27 5* Molecular sieve 5 BASF 4 .sup.[5] 6* Molecular sieve 17 BASF 13 X .sup.[ ] 7* BASF Selexsorb CDX .sup.[6] 3 8* Chemviron Carbon 15 CPG LF .sup.[7] 9* Norit GAC 1240 .sup.[7] 7 10* Chemviron Carbon 12 Aquacarb 207C .sup.[8] 11 Purolite S956 .sup.[9] 1 12 Siral 40 .sup.[10] 0.5 .sup.[1] Weakly acidic, macroporous cation exchanger based on acrylic .sup.[2] Polyacrylic porous weak acid cation ion exchange resin .sup.[3] Polyacrylic macroporous weak acid cation ion exchange resin .sup.[4] Acid active bentonite clay .sup.[5] Zeolithe (aluminosilicates mineral) .sup.[6] Alumina-based adsorbent .sup.[7] Activated carbon .sup.[8] Coconut Based Granular Activated Carbon .sup.[9] Macroporous crosslinked polymer with a phosphonic acid functionality .sup.[10] Weakly acidic silica-alumina, pore size 40 m, high level of surface acidity *comparative example

[0146] The examples show that Purolite S956 and Siral 40 show a significant behavior regarding the removal of urotropin (organically bound nitrogen) contained in the prenol stream (ethylenically unsaturated alcohol stream).

EXAMPLE 2REMOVAL OF UROTROPIN FROM A PRENOL STREAM USING SIRAL 40

[0147] A prenol stream having an initial content of 35 ppm of urotropin is passed through a column (15 mm inner diameter, 250 mm length) of 1 g of Siral 40 with a flow rate as indicated in table 2. Every 30 min, a sample was taken and the urotropin content of the treated prenol was determined by an oxidative combustion method with a chemiluminescence detector. The results are shown in table 2.

TABLE-US-00002 TABLE 2 Removal of urotropin from a prenol stream using Siral 40 t [min] prenol [mL/min] urotropin [ppm] 0 0 35 30 0.89 1 60 0.91 1 90 0.89 2 120 0.89 2 150 1.06 2 180 1.06 2 210 1.06 2 240 1.08 2 270 1.39 2 300 1.39 2 390 1.38 3

[0148] As can be seen from the results in table 2, the process of the present invention allows for significantly removing urotropin from prenol using Siral 40 as an adsorbent with no breakthrough during the duration of the test.

EXAMPLE 3OXYGEN CONSUMPTION IN THE LIQUID PHASE OXIDATION OF PRENOL

[0149] A reactor was charged with 103 g of a Pt/Al.sub.2O.sub.3 catalyst (0.9 wt.-% Pt). A feed stream containing 97 g/h of prenol and 7 g/h of water was metered through the reactor by using metering pumps. The prenol specifications (urotropin content) varied throughout the reaction periods 1 to 7 (see FIG. 1) as shown in table 3. The reaction was carried out for 59 d at an inlet pressure of 3.9 bara and an outlet pressure of 3.6 bara, and at an inlet temperature of 45 C. and an outlet temperature of 48 C. The oxygen consumption was determined quantitatively via the decrease of oxygen flow in L/h using a flowmeter. Oxygen consumption is a measure of catalyst activity.

TABLE-US-00003 TABLE 3 Prenol specifications throughout reaction periods 1 to 7 urotropin content period pre-treatment of prenol of prenol [ppm] period 1* 4 ppm period 2 adsorption .sup.[1] using 1 wt.-% of Siral 40 <2 ppm period 3* 4 ppm period 4 adsorption .sup.[1] using 0.5 wt.-% of Siral 40 <2 ppm period 5 adsorption .sup.[1] using 0.1 wt.-% of Siral 40 2 ppm period 6 adsorption .sup.[1] using 0.5 wt.-% of Siral 40 <2 ppm period 7 adsorption .sup.[1] using 0.25 wt.-% of Siral 40 <2 ppm .sup.[1] Carried out as shown in Example 2 *comparative example

[0150] The data of table 3 and FIG. 1 shows that the decline in oxygen consumption is less marked when using prenol streams pre-treated in an adsorption step according to the invention (periods 2 and 4 to 7) in comparison to non-pre-treated prenol streams (periods 1 and 3).

EXAMPLE 4SELECTIVITY TO PRENAL

[0151] A fixed-bed reactor containing a heterogeneous catalyst was filled with an unsaturated alcohol; i) treated with an adsorbent for removing nitrogen or ii) with an untreated feed containing up to 35 ppm nitrogen. In both cases, the reaction was run at 80 C. at 1.5 bar for several hours in order to compare the results regarding the catalyst activity and selectivity. The results are depicted in FIG. 2. It can be seen from FIG. 2 that the conversion to prenal was higher and the selectivity was higher when the organically bound nitrogen was removed from the prenol feed stream before the reaction, compared to the untreated prenol feed stream.