APPARATUS FOR AND PROCESS OF MAKING PSEUDOIONONE AND HYDROXY PSEUDOIONONE

Abstract

The invention relates to an apparatus (1) for producing pseudoionone and hydroxy pseudoionone. It suggests an apparatus (1) comprising first and second substantially vertically oriented reactor chambers oriented such that components flow through the first and second reactor chambers in different directions, wherein the first reactor chamber (13) is configured to receive a first component feed (C1) containing a first aqueous mixture through an inlet (15), and to produce a second aqueous mixture, and wherein the apparatus (1) comprises a mixing device (17) positioned downstream of the first component feed inlet (15) and configured to add a second component feed (C2) to the first component feed (C1) when the second aqueous mixture has formed, and the second reactor chamber (23) is configured to receive the first and second component feeds unified in the mixing device (17) from the first reactor chamber (13) and to produce a third aqueous mixture from the first and second aqueous mixtures. The invention further suggests a method and a use for producing pseudoionone and hydroxy pseudoionone.

Claims

1. An apparatus (1) for producing pseudoionone and hydroxy pseudoionone, comprising a first vertically oriented reactor chamber (13) arranged such that components flow through the first reactor chamber in a first flow direction, a second vertically oriented reactor chamber (23) in fluid communication with the first reactor chamber (13), and the second reactor chamber (23) being oriented such that components flow through the second reactor chamber (23) in a second flow direction different from the first flow direction, wherein the first reactor chamber (13) is configured to receive a first component feed (C1) containing a first aqueous mixture through an inlet (15), and to produce a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture and wherein the apparatus (1) comprises a mixing device (17) positioned downstream of the first component feed inlet (15) and configured to add a second component feed (C2) to the first component feed (C1) when the second aqueous mixture has formed, and the second reactor chamber (23) is configured to receive the first and second component feeds unified in the mixing device (17) from the first reactor chamber (13) and to produce a third aqueous mixture from the first and second aqueous mixtures.

2. The apparatus (1) of claim 1, wherein the first flow direction is oriented upwards, and the second flow direction is oriented downwards, or vice versa.

3. The apparatus (1) of claim 1, wherein the mixing device (17) is positioned on an outlet end of the first reactor chamber (13).

4. The apparatus (1) of claim 1, wherein the inlet (15) to the first reactor chamber (13) for receiving the first component feed (C1) is a first inlet, and the first reactor chamber (13) further comprises a second inlet (19) for receiving the second component feed (C2), wherein the second component feed (C2) is positioned upstream from the mixing device (17), wherein preferably, the second inlet (19) is positioned immediately upstream of the mixing device (17), or at a predetermined distance upstream of the mixing device (17), wherein preferably, the distance is selected such that the entire second component feed (C2) is drawn into the mixing device (17) without prior backwards flow inside the first reactor chamber (13).

5. The apparatus (1) of claim 1, wherein the first reactor chamber (13) comprises a tapered section (26) upstream of and tapered towards the inlet of the mixing device (17), preferably immediately upstream of the second inlet, for accelerating the flow speed of the second aqueous mixture; and/or the first reactor chamber (13) comprises a number of further mixing elements (29) upstream of the mixing device (17), the mixing elements (29) configured to harmonize a residence time of the first component feed (C1) between the inlet (15) to the first reactor chamber and the mixing device (17); and/or the second reactor chamber (23) comprises an opening (39) that is configured to be reversibly opened and closed with a corresponding cover, the opening (39) being dimensioned for introducing a packing into the second reactor chamber (23), the packing preferably comprising or consisting of loose packing material.

6. The apparatus (1) of claim 1, wherein the inlet for the first component feed (C1) is in fluid communication with a feed line (3), the feed line (3) being configured to generate the first component feed (C1) from a plurality of starter materials, wherein preferably, the feed line (3) comprises a first mixer (5) and a second mixer (9), wherein the first mixer (5) is configured to combine a first starter material feed (S1) and a second starter material feed (S2), and the second mixer (9) is positioned downstream of the first mixer (5) and configured to combine the unified first and second starter feeds (S1+S2) coming from the first mixer (5) with a third starter material feed (S3) into the first component feed (C1).

7. The apparatus (1) of claim 6, wherein the feed line (3) comprises at least one heating device (7), preferably at least one heat exchanger, configured to heat the first and second starter material feeds (S1, S2) to a predetermined temperature that is higher than a temperature of the third starter material feed (S3), wherein the at least one heating device (7) preferably is configured to heat the first and second starter materials as a function of the first, second and third starter material feed rates and the temperature of the third starter material feed such that the first component feed (C1) reaches a predetermined set point temperature prior to entering the first reactor chamber (13), and/or is positioned in between the first and second mixers (5, 9).

8. The apparatus (1) of claim 1, wherein at least one of the first and second reactor chambers (13, 23) is a reactor tube.

9. The apparatus (1) of claim 1, wherein the second reactor chamber (23) is at least partially formed as a ring chamber.

10. The apparatus (1) of claim 8, wherein the first reactor chamber (13) and second reactor chamber (23) are part of one common reactor (11), said reactor (11) having an inner tube (14) and an outer tube (25), wherein the first reactor chamber (13) is delimited by a volume of the inner tube (14), and the second reactor chamber (23) is delimited by a volume of the outer tube (25) minus the volume of the inner tube (14).

11. A process of making pseudoionone and hydroxy pseudoionone, in an apparatus (1) of claim 1, comprising the steps of: feeding a first component feed (C1) containing a first aqueous mixture into a first reactor chamber (13) through an inlet (15), the first aqueous mixture comprising first concentrations of acetone, citral and hydroxide, producing a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture, so that pseudoionone, hydroxy pseudoionone and 4-hydroxy-4-methylpentan-2-one are formed, and acetone, citral, and hydroxide are consumed, the second aqueous mixture comprising 4-hydroxy-4-methylpentan-2-one at a concentration which is higher than its concentration in the first aqueous mixture, acetone, citral and hydroxide at second concentrations which are lower than their first concentrations, and pseudoionone and hydroxy pseudoionone, and adding a second component feed (C2) to the first component feed (C1), comprising a second amount of hydroxide, downstream of the inlet (15), in particular when the second aqueous mixture has formed, supplying the first and second component feeds (C1+C2) to a second reactor chamber (23), and producing a third aqueous mixture by allowing the second aqueous mixture and the second component feed (C2) to react for a reaction time in the second reactor chamber (23), so that an additional amount of pseudoionone is formed in the third aqueous mixture in the second reactor chamber (23).

12. The process of claim 11, comprising one, several or all of the steps of: accelerating the flow speed of the second aqueous mixture prior to adding the second component feed; and/or generating the first component feed (C1) by combining a first starter material feed (S1) and a second starter material feed (S2), and subsequently combining the unified first and second starter feeds with a third starter material feed (S3) into the first component feed (C1); and/or heating the first and second starter material feeds (S1, S2) to a predetermined temperature that is higher than a temperature of the third starter material feed (S3), preferably by heating the first and second starter materials as a function of the first, second and third starter material feed rates and the temperature of the third starter material feed such that the first component feed (C1) reaches a predetermined set point temperature prior to entering the first reactor chamber (13).

13. The process of any one of claims 11, further comprising one, more or all of the steps: controlling a feed rate of the first component feed (C1) such that the first component feed (C1) has a predetermined residence time in the first reactor chamber (13) before reaching the second reactor chamber (23), preferably in the range of 3 minutes or more, further preferably 5 minutes or more; and/or harmonizing the residence time of the first component feed (C1) in the first reactor chamber (13) by providing a number of mixing elements (29); and/or providing a packing in the second reactor chamber (23); and/or determining a pressure difference between the first (13) and second reactor chamber (23), preferably at a respective location upstream and downstream of the mixing device (17).

14. The process of claim 11, further comprising the steps of: b1) determining at least one of: an amount of hydroxide unwantedly accumulating inside the first reactor chamber (13), an amount of citral entering the first reactor chamber (13), an amount of citral at the outlet or downstream of the first reactor chamber (13), an amount of citral at the outlet or downstream of the second reactor chamber (23), an amount of water at the outlet or downstream of the second reactor chamber (23), an amount of at least one of pseudoionone or hydroxy pseudoionone at the outlet or downstream of the first reactor chamber (13), an amount of at least one of pseudoionone or hydroxy pseudoionone at the outlet or downstream of the second reactor chamber (23); the reactor feed temperature of at least one of the first or second component feeds (C1, C2), the reactor residence time of at least one of the first or second component feeds (C1, C2); or a feed rate of the first component feed (C1); and b2) if the amount or amounts or the values calculated therefrom determined in b1) fall outside of respective predetermined threshold ranges, increasing or decreasing at least one of: the feed rate of the second component feed (C2) relative to the first component feed (C1), or the feed rate of that starter material feed which comprises hydroxide, preferably the third starter material feed (S3), relative to the first component feed (C1) such that the amounts determined in b1) return to inside of the threshold range.

15. A use of a system according to claim 1 for making pseudoionone and hydroxy pseudoionone.

Description

[0191] A preferred embodiment of the invention, in particular under the first and second aspects of the invention, will be described hereinafter in detail with reference to the accompanying drawings, wherein

[0192] FIG. 1: a schematic view of an apparatus for making pseudoionone and hydroxy pseudoionone according to a preferred embodiment, and

[0193] FIG. 2: a schematic detail view of a reactor of the apparatus of FIG. 1.

[0194] FIG. 1 depicts an apparatus 1 for making pseudoionone and hydroxy pseudoionone according to the invention as described in general terms hereinabove. The apparatus 1 comprises a feed line 3 for generating a first component feed C.sub.1. The feed line 3 comprises a first mixer 5 which is configured to receive and combine a first starter material feed S.sub.1 and a second starter material feed S.sub.2, wherein the first starter material feed S.sub.1 preferably contains citral, and the second starter material feed S.sub.2 preferably contains acetone.

[0195] Downstream of the first mixer 5, the feed line 3 comprises a heat exchanger 7 configured to heat the combined first and second starter material feed S.sub.1+S.sub.2 to a predetermined temperature. Downstream thereof, the feed line 3 comprises a second mixer 9 configured to combine the first and second starter material feed S.sub.1+S.sub.2 with a third starter material feed S.sub.3, preferably comprising hydroxide. The temperature of the third starter material feed S.sub.3 is preferably lower than the temperature of the first and second starter material feeds S.sub.1+S.sub.2 downstream of the heat exchanger 7. Therewith the first component feed C.sub.1 exiting the second mixer 9 preferably may be controlled to have a predetermined set point temperature.

[0196] The apparatus 1 comprises a reactor 11 which in the preferred embodiment is a double tube reactor. The reactor 11 comprises a first reactor chamber 13 having an inlet 15 and an outlet 16. The outlet 16 is at the same time the outlet portion of a mixing device 17 located on the outlet end of the first reactor chamber 13. The first reactor chamber 13 is delimited by an inner tube 14 of the reactor 11.

[0197] The reactor 11 further comprises a second reactor chamber 23 which is delimited by an outer tube 25 and the inner tube 14 of the reactor 11 and has a substantially annular shape in the region where the inner tube 14 and outer tube 25 overlap. The outlet 16 of the first reactor chamber 13 is at the same time the inlet to the second reactor chamber 23. The second reactor chamber 23 further comprises an outlet 18 configured to withdraw material from the reactor 11. While in the embodiment shown here, the second reactor chamber comprises exactly one main outlet 18, it shall be understood that the second reactor chamber is designed to comprise at least one outlet 18, and in preferred embodiments may comprise a plurality of outlets 18, meaning two, three, four, five, six, seven, eight or more outlets 18.

[0198] The inlet 15 located at the bottom end of the first reactor chamber 13 is a first inlet, and the reactor 11 further comprises a second inlet 19 upstream from the mixing device 17, wherein the second inlet 19 is configured to receive a second component feed C.sub.2 and to distribute the second component feed C.sub.2 towards the mixing device 17. In order to accomplish this, the second inlet 19 comprises a feed tube 20 that is positioned within a distance H.sub.0 of preferably 50 cm or less upstream of the inlet to the mixing device 17. The feed tube 20 comprises a number ofi.e. one or a plurality ofdistribution outlets 21, each having an orifice 27 oriented towards the mixing device 17.

[0199] Upstream of the mixing device 17, the first reactor chamber 13 comprises a tapered section 26 which is tapered an angle ? towards the mixing device 17, effective to increase the flow velocity of the first component feed C1 flowing through the first reactor chamber 13.

[0200] In the embodiment shown in FIGS. 1 and 2, the first reactor chamber 13 is a vertical upward flow column, and the second reactor chamber 23 is a substantially annular vertical downward flow column. The flow velocity in the first reactor chamber 13 is significantly greater than the flow velocity in the second reactor chamber 23 due to the dimensioning of the reactor 11, as is seen in more detail in FIG. 2. Below the first inlet 15, the first reactor chamber 13 comprises a sump 28 for gathering liquid, and particularly water and/or hydroxide, and a drainage 30 for quickly removing material from the first reactor chamber 13 if need be.

[0201] FIG. 2 shows the reactor 11 of apparatus 1 in more detail. Inside the reactor 11, the first reactor chamber 13 is provided with a plurality of mixing elements 29, which preferably are stationary X-type mixing elements. The mixing elements 29 are distributed over a column height H.sub.1. Downstream from the plurality of mixing elements 29, the first reactor chamber 13 is tapered along a length H.sub.2. In between the section comprising the mixing elements 29 and the tapered section 26, the first reactor chamber 13 and its inner tube 14 are preferably fixed to the outer tube 25 with corresponding fixing means 33, for example a plurality of spokes.

[0202] The first reactor chamber 13 comprises a perforated cover sheet 31. The cover sheet 31 is configured to promote an even flow distribution across the chamber diameter, i. e. to promote breaking the directed flow (jet) coming from the inlet tube by means of a pressure drop.

[0203] The first reactor chamber 13 has a diameter D.sub.1 which is larger than a diameter D.sub.0 of the mixing device 17, but smaller than a diameter D.sub.2 of the outer tube 25 delimiting the second reactor chamber 23. Preferably, the diameter D.sub.2 of the outer tube 25 is 1.5? to 3.0? the size of the diameter D.sub.1 of the inner tube 14. The diameter D.sub.1 of the inner tube 14 preferably is in the range of 3.0? to 5.0? the diameter D.sub.0 of the mixing device.

[0204] The column height H.sub.1 preferably is defined as a function of the diameter D.sub.1 of the first reactor chamber. Preferably, the ratio H.sub.1/D.sub.1 is in a range of 15:1 or more, further preferred in a range of 25:1 or more.

[0205] The mixing device 17 has a length H.sub.3 in the direction of flow. H.sub.3 preferably is defined as a function of the diameter D.sub.0 of the mixing device. Preferably, the ratio H.sub.3/D.sub.0 is in a range of 3:1 or more, further preferred in a range of 5:1 or more.

[0206] Above the outlet 16 of the mixing device 17, i.e. first reactor chamber 13, the second reactor chamber 23 preferably comprises a head room having a height H.sub.4. H.sub.4 preferably is defined as a function of the diameter D.sub.2 of the outer tube 25. Preferably, the ratio H.sub.4/D.sub.2 is in a range of 3:2 or more, further preferred in a range of 5:2 or more.

[0207] The second reactor chamber 23 comprises at least one lateral port 35 for taking samples. Additionally, the second reactor chamber 23 preferably comprises a lateral opening 39 that can be reversibly opened and closed for inspection of the second reactor chamber 23, and/or for installing loose packing material into the annular portion of the second reactor chamber 23. The opening 39 may be a handhole or manhole.

[0208] The reactor 11 comprises a number ofi.e. one or a plurality ofperforated sheets , for example indicated by reference sign 41, in the annular section of the second reactor chamber 23 to delimit the volume in which packing material may be arranged. Further, reactor 11 comprises at least one cover sheet 37 configured to promote even flow distribution across the diameter of the annular portion.

[0209] In the outlet end of the second reactor chamber, downstream of the outlet 18, the apparatus 1 comprises an inspection glass 43 allowing for visual inspection of the material that is withdrawn from the reactor 11. Additionally, the reactor 11 may comprise a sensor assembly 45 for determining at least one of temperature, pressure and concentration of materials in the outlet feed.

[0210] Additionally, the reactor 11 may comprise a sensor assembly 47 arranged in the region of the sump 28 and configured to determine a liquid level and/or temperature and/or hydroxide concentration within the first reactor chamber in the region of the sump 29. The drainage line 30 may further comprise a sensor assembly 49 configured to determine a hydroxide concentration and/or flow parameters.

[0211] Within the region potentially to be filled with packing material, the second reactor chamber 23 may also comprise a number ofi.e. one or a plurality oftemperature sensors 53.

[0212] In the following, preferred embodiments 1 to 15 of the process for making pseudoionone and hydroxy pseudoionone under the third aspect of the present invention are summarized. It is to be understood that each of these embodiments is at the same time also an embodiment of the invention under the first and second aspects described hereinabove and claimed hereinafter.

Embodiment 1

[0213] Process of making pseudoionone and hydroxy pseudoionone, comprising the following steps: [0214] (P1) preparing a first aqueous mixture comprising first concentrations of acetone, citral and hydroxide, by combining first amounts of water, acetone, citral and hydroxide, [0215] (P2) producing a second aqueous mixture by allowing to react for a reaction time the components of the first aqueous mixture so that [0216] pseudoionone, hydroxy pseudoionone and 4-hydroxy-4-methylpentan-2-one are formed, and [0217] acetone, citral and hydroxide are consumed, [0218] the second aqueous mixture comprising [0219] 4-hydroxy-4-methylpentan-2-one at a concentration which is higher than its concentration in the first aqueous mixture, [0220] acetone, citral and hydroxide at second concentrations which are lower than their first concentrations, and [0221] pseudoionone and hydroxy pseudoionone, [0222] and [0223] (P3) producing a third aqueous mixture by adding to the second aqueous mixture a second amount of hydroxide so that an additional amount of pseudoionone is formed in the third aqueous mixture.

Embodiment 2

[0224] Process according to Embodiment 1 [0225] wherein in step (P3): [0226] the second amount of hydroxide which is added to the second aqueous mixture is in the range of from 5 mass-% to 50 mass-%, preferably in the range of from 10 mass-% to 40 mass-%, of the first amount of hydroxide in the first aqueous mixture, [0227] and/or [0228] the concentration of dissolved hydroxide present in the third aqueous mixture is higher than the concentration of dissolved hydroxide present in the second aqueous mixture at the end of the reaction time.

Embodiment 3

[0229] Process according to any of the preceding Embodiments wherein the second amount of hydroxide is added to the second aqueous mixture in step (P3): [0230] when the molar concentration of 4-hydroxy-4-methylpentan-2-one in the second aqueous mixture has reached a value of 70 mmol/l or above;
and/or [0231] before the concentration of 4-hydroxy-4-methylpentan-2-one in the second aqueous mixture has reached a maximum or when the concentration of 4-hydroxy-4-methylpentan-2-one in the second aqueous mixture has reached a maximum; [0232] and/or [0233] when the concentration of 4-hydroxy-4-methylpentan-2-one in the second aqueous mixture has a value of ?80%, preferably of ?85% of its maximum value;
and/or [0234] 3 minutes or more, preferably 5 minutes or more, after the first aqueous mixture has been prepared, [0235] and preferably less than 25 minutes, more preferably less than 20 minutes and yet more preferably less than 15 minutes after the first aqueous mixture has been prepared;
and/or [0236] after 3 minutes or more, preferably after 5 minutes or more, of reaction time of the components of the first aqueous mixture in step (P2), [0237] and preferably after less than 25 minutes, more preferably after less than 20 minutes and yet more preferably after less than 15 minutes, of reaction time of the components of the first aqueous mixture in step (P2);
and/or [0238] when the molar ratio of 4-hydroxy-4-methylpentan-2-one:acetone in the second aqueous mixture has reached a value in the range of from 1:45 to 1:8.

Embodiment 4

[0239] Process according to any of the preceding Embodiments, wherein the first aqueous mixture and/or the second aqueous mixture and/or the third aqueous mixture are mixed or agitated mechanically.

Embodiment5

[0240] Process according to any of the preceding Embodiments wherein [0241] at least a part of the process, preferably the entire process, is conducted continuously, preferably in a tube reactor, more preferably in a tube reactor showing a flow regime which is as close as possible to plug-flow behaviour;
and/or [0242] the second amount of hydroxide is added to the second aqueous mixture continuously.

Embodiment 6

[0243] Process according to any of the preceding Embodiments, preferably according to any of claims 1 to 4, wherein at least a part of the process, preferably the entire process, is conducted discontinuously, preferably in batch-mode or semi-batch mode.

Embodiment 7

[0244] Process according to any of the preceding Embodiments, wherein the second amount of hydroxide is added to the second aqueous mixture in one single portion or in several individual portions, preferably in one single portion.

Embodiment 8

[0245] Process according to any of the preceding Embodiments, wherein the total amount of pseudoionone formed in a sequence of steps (P2) and (P3) in a reaction time t [(P2)+(P3)] is higher than the total amount of pseudoionone formed in an isolated step (P2) in an equal reaction time t [(P2)+(P3)].

Embodiment 9

[0246] Process according to any of the preceding Embodiments, wherein the total process time is in the range of from ?9 to ?30 minutes, preferably in the range of from ?12 to ?25 minutes, more preferably in the range of from >12 to ?20 minutes.

Embodiment 10

[0247] Process according to any of the preceding Embodiments, [0248] wherein [0249] the first concentration of the hydroxide in the first aqueous mixture is in the range of from 0.0015 to 0.02 mass-%, preferably of from 0.0015 to 0.0140 mass-%, more preferably in the range of from 0.0017 to 0.0070 mass-% and even more preferably in the range of from 0.0020 to 0.0065 mass-%, relative to the total mass of water and acetone present in the first aqueous mixture; [0250] and/or [0251] the molar ratio of the first amount of hydroxide present in the first aqueous mixture relative to the first amount of citral present in the first aqueous mixture is in the range of from 1.0 to 30.0 mmole/mole, preferably in the range of from 2.0 to 20.0 mmole/mole and more preferably in the range of from 2.0 to 12.0 mmole/mole; [0252] and/or [0253] the molar ratio of the total amount of acetone present in the first aqueous mixture relative to the total amount of citral present in the first aqueous mixture is in the range of from 24.0:1 to 65.5:1, preferably in the range of from 31.5:1 to 65.5:1, more preferably in the range of from 35.0:1 to 60.0:1, and yet more preferably in the range of from 37.5:1 to 50.0:1.

Embodiment 11

[0254] Process according to any of the preceding Embodiments, wherein the first amount of hydroxide which is used to prepare the first aqueous mixture and/or the second amount of hydroxide which is added to the second aqueous mixture is provided by one or more metal hydroxides, [0255] wherein preferably [0256] the one or more metal hydroxides are selected from the group consisting of: [0257] alkali metal hydroxides, preferably LiOH, NaOH and KOH; and [0258] alkaline earth metal hydroxides, preferably Mg(OH).sub.2, Ca(OH).sub.2, Sr(OH).sub.2 and Ba(OH).sub.2, [0259] wherein more preferably the one or one of the more metal hydroxides is an alkali metal hydroxide, yet more preferably selected from the group consisting of LiOH, NaOH and KOH, [0260] wherein most preferably the one or at least one of the more metal hydroxides is NaOH; [0261] and/or [0262] the one or more metal hydroxides comprise one or more metal hydroxides dissolved in a liquid phase, [0263] wherein preferably the one or more metal hydroxides comprise one or more aqueous metal hydroxides, [0264] and wherein more preferably the one or more metal hydroxides are provided in the form of an aqueous solution of one or more metal hydroxides, [0265] wherein preferably the aqueous solution has a concentration of hydroxide ions in the range of from 0.3 to 1.5 mass-%, preferably in the range of from 0.35 to 0.65 mass-% and more preferably in the range of from 0.4 to 0.6 mass-%, relative to the total mass of water and metal hydroxides present in the aqueous solution.

Embodiment 12

[0266] Process according to any of the preceding Embodiments, wherein the first aqueous mixture and/or the second aqueous mixture and/or the third aqueous mixture form liquid phases below their boiling points. [0267] and wherein preferably [0268] the reaction temperature in the first aqueous mixture and/or in the second aqueous mixture and/or in the third aqueous mixture is in the range of from 60 to 110? C., preferably in the range of from 70 to 100? C. and more preferably in the range of from 70 to 90? C.; [0269] and/or [0270] at least a part of the process, preferably the entire process, is conducted at a pressure in the range of from 150 to 1000 kPa, preferably in the range of from 150 to 700 kPa, more preferably in the range of from 200 to 650 kPa and yet more preferably in the range of from 250 to 600 kPa; [0271] and/or [0272] at least a part of the process, preferably the entire process, is conducted under adiabatic conditions.

Embodiment 13

[0273] Process according to any of the preceding Embodiments, wherein the reaction conditions, preferably the concentrations of acetone, citral and/or hydroxide, are selected or adjusted so that the first aqueous mixture forms a single liquid phase and/or the second aqueous mixture forms a single liquid phase and/or the third aqueous mixture forms a single liquid phase.

Embodiment 14

[0274] Process according to any of the preceding Embodiments, wherein the total amount of hydroxide present in the third aqueous mixture is dissolved in the liquid phase.

Embodiment 15

[0275] Process according to any of the preceding Embodiments, wherein the first aqueous mixture comprises water in a concentration in the range of from 3 to 9 mass-%, preferably in the range of from 4 to 8 mass-% and more preferably in the range of from 5 to 7 mass-%, relative to the total mass of water and acetone present in the first aqueous mixture.