JP2006036741A - Method for producing aldol condensate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a cross-aldol in which an alpha alkyl aldehyde bonds to a nonsubstituted alpha aldehyde in 1:1 ratio by efficiently carrying out cross-aldol condensation of the alpha alkyl aldehyde in the presence of the nonsubstituted alpha aldehyde. <P>SOLUTION: The cross-aldol in which the alpha alkyl aldehyde bonds to the nonsubstituted alpha aldehyde in 1:1 ratio is produced by aldol condensation of an aldehyde mixture containing 70-99 wt% alpha alkyl aldehyde and 1-30 wt% nonsubstituted alpha aldehyde. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing an aldol condensate of aldehydes. More specifically, the present invention relates to a method for producing an aldol condensate by subjecting an aldehyde (s) containing 50 wt% or more of an alpha alkyl aldehyde (s) and 50 wt% or less of an alpha unsubstituted aldehyde (s) to aldol condensation.

Feeder Organic Chemistry (above) p. 195 (Correction 2nd edition, 1955) Bithermel Organic Chemistry p. 129 (1976) Organic Industrial Chemical Handbook (1962, Asakura Shoten) p. 321

  As an example of the production of an aldol condensate, two molecules of acetaldehyde are bonded between the head (head, aldehyde group part) and the tail (tail, methyl group part next to the aldehyde) to produce acetaldol or crotonaldehyde ( Homoaldol condensation). The aldol condensation reaction is a typical head-to-tail reaction (head-to-tail reaction), where the aldehyde group is the head and the adjacent carbon is the tail. In this case, it is necessary for hydrogen to be present on the carbon adjacent to the aldehyde group (α-carbon). For example, Feather Organic Chemistry (above) p. As described in 195 (Correction 2nd edition, 1955), in the case of trimethylacetaldehyde (neopental) or benzaldehyde without this, it is said that aldol condensation does not occur. Therefore, alpha-unsubstituted aldehydes have been mainly used as raw materials for the conventional methods for producing aldol condensates of aldehydes. As the alpha unsubstituted aldehyde, for example, n-aldehydes such as acetaldehyde, propionaldehyde, and n-butyraldehyde are generally used as raw materials. For example, isobutyraldehyde (alphaalkyl), which is a byproduct of the oxo reaction of propylene, is used. Aldehyde) is not used as a raw material for the production of aldol condensates. Aldol condensates are useful, for example, as raw materials for plasticizer alcohols.

  As an example of an alpha unsubstituted aldehyde, n-butyraldehyde, for example, an aqueous caustic soda solution is added and stirred under heating to perform a homoaldol condensation reaction to obtain 2-ethylhexenal, which is then used as a conventional hydrogenation catalyst. General method for industrially producing 2-ethylhexanol (2EH) for plasticizer raw materials by adding hydrogen in the presence and hydrogenating carbon-carbon double bonds and reducing aldehyde groups to alcohols Uses only n-butyraldehyde as a raw material and does not use isobutyraldehyde.

  Two molecules of 2EH are diesterified to phthalic anhydride, and the resulting dioctyl phthalate (DOP, di-2-ethylhexyl phthalate) is obtained, for example, from Bithermel Industrial Organic Chemistry p. 129 (1976), it is the most widely used industrially in the world as a general plasticizer that is excellent for polyvinyl chloride and safe.

  The n-butyraldehyde used in this aldol condensation has been produced previously through aldol condensation of acetaldehyde, but is currently produced mainly by hydroformylation of propylene (oxo reaction).

As an example of a plasticizer raw alcohol production process, propylene oxo reaction mainly yields n-butyraldehyde as an alpha-unsubstituted aldehyde, but as a by-product is usually 10-40% alpha-alkyl aldehyde, that is, alpha-alkyl aldehyde. Isobutyraldehyde is by-produced. In general, after distilling and separating from n-butyraldehyde, it is generally hydrogenated and put on the market as an isobutanol solvent. Sometimes used as an isobutylurea fertilizer. In general, an oxo alcohol is produced by homoaldol condensation of n-butyraldehyde separated by distillation from isobutyraldehyde and hydrogenating the produced 2-ethylhexenal to produce 2EH. The product price of these isobutyraldehyde derivatives is low, and is a burden of the manufacturing cost of 2-EH.
The situation of separation of this alpha-unsubstituted aldehyde and alpha-alkyl aldehyde and whether to use alpha-alkyl aldehyde in the aldol condensation reaction are not limited to the reaction product of propylene oxo reaction. And 2-pentanal and / or alpha unsubstituted C6 aldehyde as alpha unsubstituted aldehyde by oxo reaction of pentene (s) and pentene (s) and alpha methylbutanal and / or alpha alkyl C6 aldehyde as alpha alkyl aldehyde Of course, many of the following explanations apply to the oxo reaction of propylene, followed by separation of a mixture of n-butyraldehyde and isobutyraldehyde, aldol condensation reaction, which is widely practiced in the industry. Use Carried out by way of example.

  Aldol condensation occurs when there is a hydrogen bonded to the carbon next to the carbonyl group (α-carbon). In the case of acetaldehyde, there are three hydrogens, and acetaldol or crotonaldehyde is produced by aldol condensation. In the case of acetone, there are four hydrogens bonded to the carbon (α-carbon) next to the carbonyl group, and diacetone alcohol and methyl isobutenyl ketone are produced by aldol condensation.

  Isobutyraldehyde as an example of an alpha alkyl aldehyde has one hydrogen bonded to the carbon adjacent to the carbonyl group (α-carbon), and the reaction rate of aldol condensation is much slower than that of n-butyraldehyde. It is unreacted under the aldol condensation reaction conditions of n-butyraldehyde. Isobutyraldehyde is not industrially used for aldol condensation for 2-EH production.

  In order to economically perform the aldol condensation reaction of aldehydes, the reaction system is made alkaline or acidic, and / or the temperature of the system is increased to increase the aldol condensation reaction rate. For this reason, alkali metal compounds and alkaline earth metal compounds are used as catalysts, and sulfuric acid, hydrochloric acid, phosphoric acid and the like are used as acidic substances. A solid acid or a solid alkali may be used for the catalyst.

  Conventional aldol condensations of aldehydes include alpha-unsubstituted aldehydes such as acetaldehyde {3 hydrogens present on carbon next to aldehyde group (α-carbon)}, n-butyraldehyde {carbons next to aldehyde group ( It is common to use n-aldehydes such as the presence of two hydrogens in the α-carbon).

  Since alpha alkyl aldehydes such as isobutyraldehyde are not industrially used for aldol condensation, ancillary equipment including distillation separation with n-butyraldehyde, hydrogenation equipment and tanks not only increase the construction cost of the oxo reactor. This leads to a complicated operation and an increase in operation cost, resulting in a decrease in the yield of the aldol condensation product and an increase in the cost of the product due to the absence of isobutyraldehyde. Propylene becomes expensive and is insufficient as a raw material, but isobutyraldehyde is not used as an isobutanol solvent, but the use of an isobutanol solvent complicates the oxo reactor and increases the cost due to a decrease in the yield of the aldol condensate relative to propylene. Yes.

  To that end, an improvement made industrially in the past has been to make the selectivity to alpha-unsubstituted aldehydes in the oxo reaction even greater than the selectivity to alpha-alkyl aldehydes that are not utilized for aldol condensation. Historically, with the advent of phosphorus compound-substituted rhodium compounds, especially rhodium hydrogen, CO, and triphenylphosphine complex catalysts (Wilkinson catalysts) instead of the cobalt catalysts conventionally used for oxo reaction catalysts, for example, propylene In the case of the oxo reaction, the selectivity of n-butyraldehyde / isobutyraldehyde could be improved from about 6/4 (cobalt catalyst) to about 9/1 (rhodium catalyst).

  However, even in this process, the alpha alkyl aldehyde cannot be reduced to zero. For example, in the case of an oxo reaction of propylene, it is necessary to industrially isolate isobutyraldehyde by-produced by about 10% by distillation.

  Despite the disadvantages of this equipment and operational complexity, one reason for isolating isobutyraldehyde is that alpha alkyl aldehyde isobutyraldehyde is compared to alpha unsubstituted aldehyde n-butyraldehyde under conventional aldol condensation reaction conditions. This is because the aldol condensation reactivity is low, and it remains as an unreacted substance under the conditions under which conventional n-butyraldehyde is subjected to an aldol condensation reaction, which is not economical for use in the aldol condensation reaction.

  For example, a mixture of n-butyraldehyde and isobutyraldehyde is obtained in the oxo-reaction of propylene, but the distillation separation equipment of both, the hydrogenation equipment of isobutyraldehyde, and incidental equipment including a product tank lead to an increase in the construction cost of the oxo-reactor. Not only is the equipment complicated, the operation is complicated, and the operation cost is increased, but also the disadvantage of reducing the yield of the aldol condensation product and increasing the cost of the product because isobutyraldehyde is not used for the aldol condensation. As a result of diligent research efforts, the present inventors have found that it is industrially advantageous to break the conventional common sense and not to separate the two, but to perform aldol condensation while mixing the two. In addition, isobutyraldehyde, 2-methylbutyraldehyde and alphaalkyl C6 aldehydes are subjected to cross-aldol condensation with alpha-unsubstituted aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, n-pentanal (n-pentanal, valeraldehyde) and the like. It has been found that it can be used for the production of plasticizer alcohols.

In particular, when isobutyraldehyde is used for aldol condensation, cross-aldol condensation with n-butyraldehyde having a high aldol condensation reaction rate or an alpha-unsubstituted aldehyde such as n-pentanal causes isobutyraldehyde to undergo homoaldol condensation. There is an advantage that various aldol condensates can be obtained more easily.

  The present invention is not limited to the reaction product of propylene oxo reaction, but 2-pentanal and / or alpha unsubstituted C6 as alpha unsubstituted aldehyde by oxo reaction of butene (s) and pentene (s). Of course, the present invention also applies to the case of using alphamethylbutanal and / or alphaalkyl C6 aldehyde as aldehyde and alphaalkylaldehyde. By these combinations, raw materials for plasticizer alcohol having various boiling points can be obtained, and useful plasticizers having various boiling points can be obtained. These may be an independent aldol condensing apparatus, or raw materials for plasticizer alcohol having various boiling points may be obtained by block operation in the same apparatus.

  When new aldol condensation reaction conditions are given to the reaction product, the aldol condensation catalyst may be once separated or may not be separated. A new aldol condensation catalyst may or may not be added.

  In addition, a plasticizer using a C9 or higher oxo alcohol (s) obtained from a cross-aldol condensation reaction product of isobutyraldehyde and an alpha unsubstituted aldehyde (s) having a carbon number of C5 or higher has a heat resistance higher than that of DOP. Since this is considered to be further improved, there is no possibility of a decrease in the heat resistance of the plasticizer due to the use of isobutyraldehyde for the aldol condensation. In addition, an economically advantageous plasticizer can be obtained with little consideration of a decrease in plasticizer performance. In the case of alphamethylbutanal, C8 aldehyde is obtained from C7 aldehyde and propionaldehyde by cross-aldol condensation with acetaldehyde. In the case of alpha alkyl C6 aldehyde, C8 aldehyde is obtained from acetaldehyde and C9 aldehyde is obtained from propionaldehyde, which can be directed to the production of various plasticizer alcohols.

  For example, even if the head-to-tail reaction, which is an aldol condensation between isobutyraldehyde and isobutyraldehyde, is difficult, if a small amount of n-butyraldehyde is added to cause aldol condensation in the presence of a large excess of isobutyraldehyde, the aldehyde group of isobutyraldehyde Cross aldol condensation, where the (head) reacts with the methylene group next to the aldehyde group of n-butyraldehyde (tail, with two hydrogens), is thought to occur easily. In addition, if a cross-aldol condensation reaction between isobutyraldehyde and aldehyde (s) having a carbon number of 5 or more is performed, and a plasticizer using alcohol (s) obtained through the reaction is obtained, the heat resistance of the plasticizer is obtained. Has the advantage of improving.

  Therefore, even when an alpha alkyl aldehyde is obtained as a by-product of, for example, about 10% of the oxo reaction, a cross-aldol condensation is directly performed on the mixture of the two without distilling with, for example, n-pentanal as an alpha unsubstituted aldehyde, Even if about 20% of crossover (hereinafter referred to as ni-) C10 alcohol is mixed by hydrogenation, a C10 alcohol mixture containing 80% 2-propylheptanol (2PH) is obtained to obtain phthalic anhydride and diester. A much cheaper plasticizer can be obtained as diisododecyl phthalate (hereinafter referred to as (n−n−n−i−) DIDP, DIDP) (the one resulting from crossed aldol condensation is referred to as (n−i) DIDP). In this case, the boiling point of the C10 alcohol itself is higher than the boiling point of 2EH, so that the boiling point of DIDP is slightly higher than that of DOP even though it is slightly lower than DDP derived from 2PH (2PH diester to phthalic anhydride). , DIDP containing about 20% (ni-) DIDP has better heat resistance than DOP. In addition, (ni-) DIDP has a higher degree of branching than DDP, but this difference does not significantly affect the plasticizer performance.

  Also, in this case, for example, when alphamethylbutyraldehyde is obtained as an alpha alkyl aldehyde as a by-product of the oxo reaction, aldol condensation is directly performed on the mixture of the two without distilling off, for example, n-pentanal as an alpha unsubstituted aldehyde. Hydrogenation to obtain a C10 alcohol mixture mainly containing 2-propylheptanol (2PH) and phthalic anhydride and diester can be used as a plasticizer as DIDP.

  As the alpha alkyl aldehyde and the alpha unsubstituted aldehyde used as the raw material of DIDP, an oxo reaction product of monoolefins in the C4 fraction can be suitably used. This may be a C4 fraction of an ethylene plant. Usually, spent BB (raffinate-1) after butadiene extraction or raffinate BB (raffinate-2) after isobutylene is separated therefrom can be suitably used. FCCBB can be used in the same manner, and raffinate BB after isobutylene is separated therefrom can also be suitably used.

  When the pentene (s) oxo reaction is carried out, it may be the C5 fraction of an ethylene plant, and it is usually preferred to partially hydrogenate alkylacetylenes and dienes to produce monoolefins and carry out the oxo reaction. Similarly, the C5 fraction in the FCC apparatus can be suitably used.

  In both cases, it is not necessary to separate both the alpha-unsubstituted aldehyde and the alpha alkyl aldehyde, and the separation section is not required. Therefore, the industrial process can be simplified, and the size of the downstream portion of the process can be reduced because the raw material unit is small. The device cost is reduced because it is small.

Therefore, even in this case, even if the head-to-tail reaction, which is a homoaldol condensation between alphamethylbutyraldehyde and alphamethylbutyraldehyde, is difficult, a small amount of n-pentanal is added to the aldol in the presence of a large excess of alphamethylbutyraldehyde. When condensed, the aldehyde group (head) of alphamethylbutyraldehyde reacts with the methylene group next to the aldehyde group of n-pentanal (tail, with two hydrogens), cross-aldol condensation (reaction of ni-aldehyde) There is a method in which (ni-) C10 alcohol is obtained. In addition, there is a utilization method derived from cross-aldol condensation of alphamethylbutyraldehyde with n-butyraldehyde and / or C4 aldehydes to C9 alcohols.
On the other hand, when two molecules of n-pentanal react with each other to obtain an aldol condensation product, it can be said to be homoaldol condensation (which may be referred to as nn-aldehyde reaction).

  According to the present invention, if the alpha alkyl aldehyde obtained by the oxo reaction is 50% or less and the simultaneously present alpha unsubstituted aldehyde is 50% or more of the mixed aldehyde raw material, the alpha alkyl aldehyde and the alpha unsubstituted aldehyde are used. It is theoretically possible to readily utilize the entire amount of alpha alkyl aldehyde for alcohol as a crossed aldol product with a molar ratio of 1: 1 with. In this case, the carbon number of the alpha alkyl aldehyde and the alpha unsubstituted aldehyde do not necessarily have to be the same.

  In industrial oxo reactions, aldo-free aldehydes (n-aldehydes) are usually about 60-90%, and by-product alpha alkyl aldehydes are about 10-40% of aldol condensation raw materials. By-product alpha alkyl aldehydes do not require separation from alpha-unsubstituted aldehydes (n-aldehydes), and can be used up for oxo alcohols without any practical problems. In this case, of course, the homoaldol condensation of the stoichiometrically remaining alpha-unsubstituted aldehydes occurs easily. Even if the alpha alkyl aldehyde produced by the oxo reaction exceeds 10%, it is 50% or less, and as long as the alpha unsubstituted aldehyde present at the same time is 50% or more, there is no problem.

  In industrial oxo reactions, aldo-free aldehydes (n-aldehydes) are usually about 60-90%, and by-product alpha alkyl aldehydes are about 10-40%. According to the separation method, alpha-unsubstituted aldehydes (n-aldehydes) are about 50%, by-product alpha alkyl aldehydes are about 50% aldol condensation raw materials and substantially alpha-unsubstituted aldehydes (n-aldehydes). Of course, it is also possible to separate the aldehydes into aldols separately.

  The aldol condensation reaction according to the present invention can be carried out in various reaction systems, whether it is a batch reactor, a batch continuous reactor or a continuous reactor. It can also be implemented in a continuous two-stage reactor connected in series. In this case, the first reaction tower in the previous stage can be named as the first (nn-aldehyde) reaction tower, and mainly reacts with alpha-unsubstituted aldehyde (in the case of oxo reaction product of propylene, n-butyraldehyde). To leave unreacted alpha alkyl aldehyde (isobutyraldehyde in the case of the oxo reaction product of propylene) and a 1: 1 molar ratio of alpha unsubstituted aldehyde.

  Next, an unreacted alpha alkyl aldehyde remaining in the front stage and a 1: 1 molar ratio of the alpha unsubstituted aldehyde are then converted into a crossed aldol in a second molar ratio of the alpha alkyl aldehyde and the alpha unsubstituted aldehyde in the subsequent stage. The product is used in such a way that it can participate in the reaction as a whole.

  In this case, an excess of an alpha-unsubstituted aldehyde may be added again so that the entire amount of alpha-alkyl aldehyde reacts stoichiometrically in the subsequent stage. For example, when the alpha alkyl aldehyde is isobutyraldehyde, n-butyraldehyde having the same molecular weight may be added, or an alpha unsubstituted aldehyde having a different molecular weight may be added. This may be added separately from the oxo reactants.

  Unsaturated aldehydes obtained through this aldol condensation reaction are derived into oxo alcohols for plasticizers by a conventional hydrogenation reaction. The produced oxo alcohols may be mixed with other alcohols having different molecular weights and reacted to carry out different types of phthalic anhydride diesterification.

  In the present invention, cross-aldol condensation is used, and an oxo reactant can be used in accordance with various olefin raw material circumstances. If 1-butene is preferentially obtained by partially hydrogenating butadiene, this can also be used as a suitable raw material. Similarly, isobutylene and 2-butene can be used as suitable raw materials. C5 olefins and oxo reactants from ethylene can also be used as cross-aldol condensation raw materials, and are flexible for various raw materials. The raw material should just be an olefin cheaper than propylene.

  These are preferably monoolefins.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the scope of the best mode and can be easily analogized by those skilled in the art. Of course, it can be extended to a range.

A first stainless steel cylindrical reaction column of 20 mm in inner diameter and 5 m in total length filled with magnetic Raschig rings having an outer diameter of 3 mm shown in FIG. 1 and filled with a porosity of 35% is vertically placed, 10 wt% alphamethylbutyraldehyde and 90 wt% n-pentanal. The mixture was passed through 100 g / hr and 1.5% caustic soda aqueous solution 10 g / hr from bottom to top at 0.3 MPa and 90 ° C. From the outlet, a homoaldol condensation product (A) in which only n-pentanals were subjected to homoaldol condensation, and a mixture (B) of 90 wt% unreacted alphamethylbutyraldehyde and 10 wt% n-pentanal were obtained.
A homoaldol condensation product (A) in which only a mixture of 90% by weight of unreacted alphamethylbutyraldehyde and 10% by weight of n-pentanal is subjected to vacuum distillation by homoaldol condensation between n-pentanal after separation of a 1.5% aqueous caustic soda solution. Separate and once stored in the aldol product tank. Subsequently, 10 g / hr of this mixture, 90 g / hr of substantially alphamethylbutyraldehyde, and 10 g / hr of 5% sodium hydroxide aqueous solution were passed from the bottom to the top at 0.3 MPa and 130 ° C. From the outlet, a 1: 1 cross-aldol condensation product of n-pentanal and alphamethylbutyraldehyde (C) and a mixture of substantially unreacted alphamethylbutyraldehyde (D) are obtained. (D) was used for circulation to the second reaction tower.

  Contents with a rotary stirrer, a thermometer, a dropping funnel and a vent valve shown in FIG. 2 are placed in an autoclave which is a 500 ml batch reactor, and 100 g of a mixture of 10 wt% isobutyraldehyde and 90 wt% n-butyraldehyde is added to 0.2 MPa. The mixture was appropriately heated or cooled to keep at 100 ° C., and a 1.5% sodium hydroxide aqueous solution was added dropwise at a rate of 1 g / min with vigorous stirring. The dropping was completed in 30 minutes, and then the stirring was continued at 100 ° C. for 30 minutes. About 90 g of a homoaldol condensation product obtained by homoaldol condensation of n-butyraldehyde and about 10 g of unreacted isobutyraldehyde remained in the flask. This was separated by distillation under reduced pressure, and about 10 g of unreacted isobutyraldehyde was recovered from the top of the column and stored in an intermediate tank. Subsequently, 100 g of isobutyraldehyde and 5 g of 5% caustic soda aqueous solution were placed in an autoclave which is a 500 ml batch reactor equipped with a rotary stirrer, a thermometer, a dropping funnel and a vent valve shown in FIG. The mixture was appropriately heated or cooled to keep it, and n-pentanal was added dropwise at a rate of 3.3 g / min with vigorous stirring. The dropping was completed in 33 minutes, and then stirring was continued at 120 ° C. for 30 minutes. In the flask, about 200 g of a product obtained by cross-aldol condensation of n-pentanal and isobutyraldehyde 1: 1 was left.

2 g of alphamethylbutyraldehyde 100 g / hr, 5% aqueous caustic soda solution is added to an autoclave which is a 500 ml batch reactor with a rotary stirrer, a thermometer, a dropping funnel and a vent valve shown in FIG. The mixture was appropriately heated or cooled and n-pentanal was added dropwise at a rate of 2 g / min with vigorous stirring. The dropwise addition was completed in 30 minutes, and then the mixture was stirred at 120 ° C. for 30 minutes. About 40 g of a cross-aldol condensation product obtained by cross-aldol condensation of about 120 g of n-pentanal and alphamethylbutyraldehyde at a 1: 1 molar ratio and unreacted alphamethylbutyraldehyde remained in the flask.

  2 g of 2-methylpentanal and 5% caustic soda aqueous solution are put in an autoclave which is a 500 ml batch reactor with a rotary stirrer, a thermometer, a dropping funnel and a vent valve shown in FIG. The mixture was appropriately heated or cooled to keep it, and propionaldehyde was added dropwise at a rate of 3.3 g / min with vigorous stirring. The dropping was completed in 33 minutes, and then stirring was continued at 120 ° C. for 30 minutes. In the flask, about 200 g of a product obtained by cross-aldol condensation of propionaldehyde and 2-methylpentanal 1: 1 was left.

2 g of alphamethylbutyraldehyde 100 g / hr, 5% aqueous caustic soda solution is added to an autoclave which is a 500 ml batch reactor with a rotary stirrer, a thermometer, a dropping funnel and a vent valve shown in FIG. The mixture was appropriately heated or cooled and n-pentanal was added dropwise at a rate of 2 g / min with vigorous stirring. The dropwise addition was completed in 30 minutes, and then the mixture was stirred at 120 ° C. for 30 minutes. About 40 g of a cross-aldol condensation product obtained by cross-aldol condensation of about 120 g of n-pentanal and alphamethylbutyraldehyde at a 1: 1 molar ratio and unreacted alphamethylbutyraldehyde remained in the flask.

A stainless steel first reaction tower having an inner diameter of 20 mm and a total length of 5 m filled with a magnetic Raschig ring having an outer diameter of 3 mm shown in FIG. 3 filled with a porosity of 35% is vertically set, and 20 wt% of alphamethylbutyraldehyde and 80 wt% of n-pentanal. The mixture was passed through 100 g / hr and 1.5% caustic soda aqueous solution 10 g / hr from top to bottom at 0.3 MPa and 90 ° C. From the outlet, a homoaldol condensation product (A) in which only n-pentanals were subjected to homoaldol condensation, and a mixture (B) of 95% by weight of unreacted alphamethylbutyraldehyde and 5% by weight of n-pentanal were obtained.
After separation of 1.5% caustic soda aqueous solution, unreacted mixture of 95% by weight of unreacted alphamethylbutyraldehyde and 5% by weight of n-pentanal is subjected to vacuum distillation with the reaction product to form a homoaldol condensation product in which only n-pentanal is condensed with each other Separated from product (A) and once stored in the aldol product tank. Subsequently, 20 g / hr of this unreacted mixture, 10 g / hr of 5% aqueous caustic soda solution, 20 g / hr of a mixture of 20 wt% alphamethylbutyraldehyde and 80 wt% n-pentanal, and unreacted of this second reaction column Along with the mixture (D) with alpha methyl butyraldehyde, a stainless steel cylindrical second reaction tower having an inner diameter of 20 mm and a total length of 5 m, filled with a magnetic Raschig ring having an outer diameter of 3 mm shown in FIG. It was passed at 3 MPa and 130 ° C. From the outlet, a 1: 1 cross-aldol condensation product of n-pentanal and alphamethylbutyraldehyde (C) and a mixture of substantially unreacted alphamethylbutyraldehyde (D) are obtained, 5% caustic soda After separating the aqueous solution, the unreacted substance (D) was separated from the reactant in the unreacted substance separation tower and used for circulation to the second reaction tower.

Comparative Example 1

  Contents with a rotary stirrer, thermometer, dropping funnel and vent valve Put 500g of isobutyraldehyde and 90g of n-butyraldehyde in a 500ml autoclave, heat or cool appropriately at 90 ° C, and stir vigorously with 2% sodium hydroxide aqueous solution. The solution was added dropwise at a rate of 0.2 g / min. The dropping was completed in 30 minutes, and then stirred at 0.3 MPa and 120 ° C. for 30 minutes. In the flask, a homoaldol product obtained by homoaldol condensation of about 90 g of n-butyraldehyde with each other and 10 g of unreacted isobutyraldehyde remained.

Comparative Example 2

  Contents with a rotary stirrer, thermometer, dropping funnel and vent valve 500 g of autoclave, 10 g of isobutyraldehyde and 90 g of n-butyraldehyde are heated or cooled appropriately at 0.3 MPa, 100 ° C., and 2% with vigorous stirring. An aqueous caustic soda solution was added dropwise at a rate of 0.2 g / min. The dropping was completed in 30 minutes, and then the mixture was stirred at 30 MPa and 120 ° C. for 30 minutes. In the flask, a homoaldol condensation product in which about 90 g of n-butyraldehyde is homoaldol-condensed between two molecules and a cross-aldol condensation in which 20 g of n-butyraldehyde and isobutyraldehyde are cross-aldol-condensed in a 1: 1 molar ratio. About 90 g of product and unreacted isobutyraldehyde remained.

The invention's effect

  As described above, according to the present invention, conventionally, when aldol condensation of an alpha alkyl aldehyde and an alpha unsubstituted aldehyde is carried out, a crossed aldol in which the unreacted alpha alkyl aldehyde is also bonded to the alpha unsubstituted aldehyde in a one-to-one relationship. Can be linked to a plasticizer alcohol.

  According to the present invention, a larger amount of plasticizer alcohol can be easily produced from raw materials.

FIG. 1 is a schematic diagram of an aldol condensation continuous reaction showing one embodiment of the present invention.
In FIG. 1, V1 is a first-stage aldol condensation batch type continuous reaction apparatus {described as a first (n-aldehyde) reaction column} as a first stage, and V2 is a second-stage aldol condensation as a second stage. It is a batch-type continuous reaction apparatus {denoted as a second (ni-aldehyde) reaction tower}. In the first-stage aldol condensation reaction apparatus, a homoaldol condensation product (denoted as n-aldol product) is mainly produced from an alpha-unsubstituted aldehyde and can be isolated by separating it from the unreacted substance after the outlet. is there. If this is put into a T1: n-aldol product tank, in the case of an oxo reaction product of propylene, 2-ethylhexanal is the main, and 2-EH is obtained by hydrogenation. In the case of an oxo reaction product of 1-butene, 2-propylheptanal is predominant, and 2-PH is obtained by hydrogenation.
In the second stage aldol condensation reactor of V2, a cross-aldol product (described as ni-aldol product) in a 1: 1 molar ratio of alpha alkyl aldehyde to alpha unsubstituted aldehyde is converted from alpha unsubstituted aldehyde. It forms as a mixture with the homoaldol condensation product.

FIG. 2 is a schematic diagram of an aldol condensation batch continuous reaction system showing one embodiment of the present invention.
In FIG. 2, V is an aldol condensation batch type continuous reaction apparatus.
V1 ... first-stage aldol condensation batch-type continuous reaction apparatus, V2 ... second-stage aldol condensation batch-type continuous reaction apparatus, S ... unreacted substance separation tower, T1 ... n-aldol product tank, T2 ... n -I-Aldol product tank, ST ... stirrer, V ... stirring reaction tank, T ... reaction product tank

FIG. 3 is a schematic diagram of an aldol condensation two-stage continuous separation reaction system showing an embodiment of the present invention.
In FIG. 3, V1 is the first-stage aldol condensation batch-type continuous reaction apparatus {described as the first (nn-aldehyde) reaction column} as the first stage, and V2 is the second-stage as the second stage. It is an aldol condensation batch type continuous reaction apparatus {denoted as a second (ni-aldehyde) reaction tower}. In the first-stage aldol condensation reaction apparatus, a homoaldol condensation product (denoted as n-aldol product) is mainly produced from an alpha-unsubstituted aldehyde and can be isolated by separating it from the unreacted substance after the outlet. is there. If this is put into the T1: nn-aldol product tank, in the case of the oxo reaction product of propylene, 2-ethylhexanal is the main, and 2-EH is obtained by hydrogenation. In the case of an oxo reaction product of 1-butene, 2-propylheptanal is predominant, and 2-PH is obtained by hydrogenation.
In the second stage aldol condensation reactor of V2, a cross-aldol product (described as ni-aldol product) in a 1: 1 molar ratio of alpha alkyl aldehyde to alpha unsubstituted aldehyde is converted from alpha unsubstituted aldehyde. It forms as a mixture with the homoaldol condensation product.

It is a schematic diagram of aldol condensation continuous reaction. It is a schematic diagram of an aldol condensation batch type continuous reaction system. It is a schematic diagram of an aldol condensation two-stage continuous separation type reaction system.

Explanation of symbols

V1 ... first-stage aldol condensation batch-type continuous reaction apparatus, V2 ... second-stage aldol condensation batch-type continuous reaction apparatus, S ... unreacted substance separation tower, T1 ... n-aldol product tank, T2 ... n -I-Aldol product tank, ST ... stirrer, V ... stirring reaction tank, T ... reaction product tank V0: oxo reactant tank, F1 ... first caustic soda catalyst tank, F2 ... second caustic soda catalyst tank S1 ... n- n unreacted substance separation tower, S2... n-i unreacted substance separation tower

Claims (7)

  A method for producing an aldol condensate using, as a raw material, a mixture of aldehyde (s) containing 50 wt% to 99.9 wt% alpha alkyl aldehyde (s) and 50 wt% to 0.1 wt% alpha-unsubstituted aldehyde (s).   The aldehyde (s) mixture containing 50 wt% to 99.9 wt% of the alpha alkyl aldehyde (s) and 50 wt% to 0.1 wt% of the alpha unsubstituted aldehyde (s) is used as a raw material. A process for producing a crossed aldol condensate with a substituted aldehyde (s).   Aldol condensation is performed in a first-stage reactor on an aldehyde (s) mixture containing 5 wt% to 50 wt% alpha alkyl aldehyde (s) and 50 wt% to 95 wt% alpha-unsubstituted aldehyde (s). The aldehyde (s) containing 50 wt% to 99.9 wt% of the alpha alkyl aldehyde (s) obtained as a product and 50 wt% to 0.1 wt% of the alpha unsubstituted aldehyde (s) as the remaining raw material The process according to claim 1, wherein the aldol condensate is produced in a reactor.   Aldol condensation is performed in a first-stage reactor on an aldehyde (s) mixture containing 5 wt% to 50 wt% alpha alkyl aldehyde (s) and 50 wt% to 95 wt% alpha-unsubstituted aldehyde (s). The aldehyde (s) containing 50 wt% to 99.9 wt% of the alpha alkyl aldehyde (s) obtained as a product and 50 wt% to 0.1 wt% of the alpha unsubstituted aldehyde (s) as the remaining raw material The process of claim 1, wherein the reactor produces a crossed aldol condensate of alpha alkyl aldehyde (s) and alpha unsubstituted aldehyde (s).   A first-stage aldol condensation is performed on an aldehyde (s) mixture containing 5 wt% to 50 wt% alpha alkyl aldehyde (s) and 50 wt% to 95 wt% alpha unsubstituted aldehyde (s). The aldehyde (s) containing 50 wt% to 99.9 wt% of the alpha alkyl aldehyde (s) obtained as an unreacted substance after separation and 50 wt% to 0.1 wt% of the alpha unsubstituted aldehyde (s) is used as the remaining raw material. The process according to claim 3, wherein the second-stage aldol condensate is produced.   A first-stage aldol condensation is performed on an aldehyde (s) mixture containing 5 wt% to 50 wt% alpha alkyl aldehyde (s) and 50 wt% to 95 wt% alpha unsubstituted aldehyde (s). The aldehyde (s) containing 50 wt% to 99.9 wt% of the alpha alkyl aldehyde (s) obtained as an unreacted substance after separation and 50 wt% to 0.1 wt% of the alpha unsubstituted aldehyde (s) is used as the remaining raw material. 4. The process of claim 3, wherein a crossed aldol condensate of alpha alkyl aldehyde (s) and alpha unsubstituted aldehyde (s) is produced in a second stage reactor.   Use acetaldehyde, propionaldehyde, n-butyraldehyde, 2-pentanal and / or alpha unsubstituted C6 aldehyde as the alpha unsubstituted aldehyde and use isobutyraldehyde, alpha methyl butanal and / or alpha alkyl C6 aldehyde as the alpha alkyl aldehyde The method for producing the aldol condensate according to claim 1.

Images