Method and apparatus for producing aldehydes

Abstract

本発明は、C2n不飽和アルデヒド(式中、nは3以上かつ6以下の範囲である)の製造方法であって、(iv)アルドール化反応からの粗アルドール流を、蒸留条件下で操作される粗アルドール蒸留塔に通して、粗アルドール流と比較して増加した濃度のC2n不飽和アルデヒド、水及び重質物を有する塔底流と、未反応Cnアルデヒド、Cn-1アルカン、Cn-1アルケン、及び粗アルドール流と比較して減少した濃度のC2n不飽和アルデヒド、水及び重質物を含む塔頂流とを形成することと;(v)粗アルドール蒸留塔からの塔頂流を、第1の凝縮器ゾーンであって、粗アルドール蒸留塔からの塔頂流と比較して増加した濃度の未反応Cnアルデヒド及び水を含む第1の凝縮流と、Cn-1アルカン、Cn-1アルケン、及び粗アルドール蒸留塔からの塔頂流と比較して減少した濃度の未反応Cnアルデヒド及び水を含む塔頂流とを提供するように構成されている、第1の凝縮器ゾーンに通すことと;(vi)第1の凝縮器ゾーンからの塔頂流を、第2の凝縮器ゾーンであって、第1の凝縮器ゾーンからの塔頂流の少なくとも一部を凝縮して、Cn / Cn-1凝縮物を提供するように構成されている、第2の凝縮器ゾーンに通すことと;を含み、Cn / Cn-1凝縮物の少なくとも一部が、回収されて、粗アルデヒド蒸留塔の上流に又は粗アルデヒド蒸留塔に戻される、方法を提供する。

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for the production of aldehydes. Specifically, the method and apparatus according to the present invention provide improved raw material efficiency in the production of synthetic aldehydes, more specifically 2-alkylalkenals. [Background technology]

[0002] Synthetic aldehydes such as 2-alkylalkenals are generally used as intermediates in the production of alcohols such as 2-alkylalkanols, while alcohols themselves are used in a wide variety of applications in the chemical industry, including as solvents, fuels, and chemical intermediates in the synthesis of organic compounds. A wide variety of alcohols are produced globally every year. For certain alcohols (e.g., ethanol), biosynthesis methods such as fermentation may be suitable for production. However, for longer-chain and branched-chain alcohols, synthetic production is generally required.

[0003] Existing methods for the synthesis of aldehydes such as 2-alkylalkenals involve a step of hydroformylating an olefin in the presence of a catalyst (also known as the "oxo" process), followed by an aldolation step. Hydroformylation introduces a formyl group into an unsaturated olefin to provide an aldehyde. Hydroformylation can be achieved by contacting the olefin with synthesis gas (a mixture of carbon monoxide and hydrogen). Once the aldehyde is formed, hydrogenation reduces the aldehyde to the corresponding alcohol.

[0004] When longer-chain or branched-chain alcohols are required, this process may involve an aldolation step to condense two aldehydes, followed by dehydration, thereby providing an unsaturated aldehyde such as a 2-alkylalkenal. Such aldolation reaction products are typically called α,β-unsaturated aldehydes. When the aldolation reaction occurs between two identical aldehydes, the α,β-unsaturated aldehyde is called an autocondensation product. When the aldolation reaction occurs between two different aldehydes, the α,β-unsaturated aldehyde is called a cross-condensation product. The aldolation process is typically catalyzed with a base or an acid.

[0005] Next, the unsaturated aldehyde is reduced by hydrogenation to provide the corresponding saturated alcohol.

[0006] Given the broad utility of alcohols, particularly 2-alkyl alkanols, it is desirable to produce alcohols cost-effectively, on an industrial scale, and with maximum yield and purity.

[0007] Therefore, an object of the present invention is to improve the raw material efficiency and yield in the preparation of aldehydes, particularly 2-alkylalkenals, produced by industrial processes. Such advantages are beneficial in themselves and also benefit the overall raw material efficiency and yield in the production of alcohols, particularly 2-alkylalkanols, in which aldehydes are intermediates. [Overview of the project]

[0008] The inventors of this invention have found that C can be converted via an aldolization reaction. n Aldehyde to C 2n The present invention provides a novel method and apparatus for producing unsaturated aldehydes (wherein n is in the range of 3 to 6), more specifically 2-alkylalkenals, and even more specifically 2-propylhepta-2-enal. Advantageously, the method and apparatus of the present invention increase the yield of the product and increase the efficiency of the raw materials.

[0009] The method and apparatus of the present invention enable an increase in the recovery rate of unreacted C n aldehydes. The distillation column is configured to separate the reaction mixture provided by the aldolization process. More specifically, the present invention relates to unreacted C n a first condensate stream containing aldehydes, C n-1 alkanes and C n-1 alkenes together with the remaining unreacted C n aldehydes in C n / C n-1 condensate, and C n-1 any vapor stream containing alkanes and C n-1 alkenes are recovered by providing a first condenser zone and a second condenser zone at the top of the distillation column. C n-1 alkanes and C n-1 alkenes are present in the feed to the hydroformylation reaction and are thus typically present in the C n aldehyde feed stream to the aldolization reaction. Small amounts of C n-1 alkanes and C n-1 alkenes typically slip through the aldolization reaction and are described herein as C n from aldehydes to C n-1 alkanes and C n-1 it is possible to adjust the temperature at the bottom of the crude aldehyde distillation column used to at least partially separate the alkenes. C n aldehydes, C n-1 alkanes and C n-1 alkenes accumulate at the top of the aldol distillation column, are concentrated to a high level due to their hydrophobicity, and are conventionally discharged to limit their accumulation. Typically, this is achieved by partially condensing the top of the crude aldol distillation column in a single condensation step, for example, cooling to about 80 °C in the case of pentanal used in the synthesis of 2-propylhepta-2-enal. This results in losses of the C n aldehyde from the process.

[0010] According to a first aspect of the present invention, C2n A method for producing an unsaturated aldehyde (wherein n is in the range of 3 or more and 6 or less), (I C n-1 An olefin stream containing alkenes is supplied to a hydroformylation reactor, and the olefin stream is brought into contact with a hydroformylation gas stream containing hydrogen and carbon monoxide to produce a hydroformylation reaction. n Aldehyde, C n-1 Alkanes, and C n-1 To provide a crude aldehyde stream containing alkenes, (ii) The crude aldehyde stream is supplied to the crude aldehyde distillation zone, which is operated under distillation conditions, C n Aldehyde, C n-1 Alkanes, and C n-1 It contains alkenes and has an increased concentration of C relative to the crude aldehyde stream. n The bottom flow containing aldehydes and the increased concentration of C compared to the crude aldehyde flow. n-1 Alkanes, and C n-1 To form a top-down flow containing alkenes, (iii) The bottom flow from the crude aldehyde distillation column is supplied to the aldolization reactor under condensation and dehydration conditions, C n This reaction produces the aldolization of an aldehyde, resulting in the aldol product C. 2n Unsaturated aldehyde, unreacted C n Aldehyde, C n-1 Alkane, C n-1 To provide a crude aldol flow containing alkenes, water, and heavy substances, (iv) The crude aldol stream is passed through a crude aldol distillation column operated under distillation conditions, and the increased concentration of C compared to the crude aldol stream is measured. 2n The bottom flow of the tower contains unsaturated aldehydes, water, and heavy substances, and unreacted C n Aldehyde, C n-1 Alkane, C n-1 Alkenes and C with reduced concentration compared to crude aldol streams 2n To form a top flow containing unsaturated aldehydes, water, and heavy substances, (v) The top flow from the crude aldol distillation column is in the first condenser zone, and the concentration of unreacted C is increased compared to the top flow from the crude aldol distillation column. n A first condensation flow containing aldehydes and water, and C n-1 Alkane, C n-1 Alkenes and unreacted C, with reduced concentration compared to the top flow from the crude aldol distillation column. n It is configured to pass the flow through a first condenser zone, which is configured to provide a top flow containing aldehydes and water. (vi) The top flow from the first condenser zone is transferred to the second condenser zone, which condenses at least a portion of the top flow from the first condenser zone, C n / C n-1 This includes passing the material through a second condenser zone configured to provide condensates, C n / C n-1 A method is provided in which at least a portion of the condensate is recovered and returned to or upstream of the crude aldehyde distillation column.

[0011] Advantageously, the crude aldehyde distillation zone is C n-1 Alkanes and C n-1 From Alken C n It is more effective in separating aldehydes and unreacted C n This facilitates efficient recycling of aldehydes, returning them to the aldolization process rather than discarding them for discharge. n-1 Alkanes and C n-1 Alkene recovery also allows the flow to be transported as a liquid rather than a low-pressure gas, thereby enabling the recovery of C n-1 Alkanes and C n-1 Increase the value of the Alken method.

[0012] In the method of the present invention, n is appropriately 4, 5, or 6, typically 4 or 5, preferably 5. Therefore, C in the olefin feed stream n-1 The alkene may appropriately be propene or butene, preferably butene, for example, buto-1-ene. nThe aldehyde is preferably a C4, C5, or C6 aldehyde, typically C4 or C5, preferably C5, i.e., pentanal. After undergoing the aldolization reaction, the aldol product C 2n C provides unsaturated aldehydes. n Most aldehydes are straight-chain aldehydes, such as varelualdehyde (pentanal). Typically, branched aldehydes are total carbon. n Aldehydes are present in amounts of up to 10 mol%, preferably up to 7.5 mol%. For example, C n When the aldehyde is pentanal, 3-methylbutanal and 2-methylbutanal may exist. Such isomers can typically be produced during the hydroformylation process. 2n Unsaturated aldehydes are preferably C8, C 10 or C 12 Unsaturated aldehydes, typically C8 or C8. 10 Unsaturated aldehyde, preferably C 10 C 2n The unsaturated aldehyde may also be a 2-alkyl alkenal. Preferably, C 2n The aldehyde is 2-propylhepta-2-enal.

[0013] C n-1 Alkanes are C n-1 Alkanes, or isomers C n-1 It may also be a mixture of alkanes. For example, n is 5 and C n In a preferred embodiment, where the aldehyde is pentanal, C n-1 Alkanes include n-butane and i-butane, typically n-butane. C present in the method of the present invention n-1 The alkanes may be transported from the olefin feed to the hydroformylation step and / or produced during hydroformylation. n-1 Alkenes are C n-1 Alkenes, or isomer C n-1 It may also be a mixture of alkenes. For example, n is 5 and C n In a preferred embodiment, where the aldehyde is pentanal, C n-1The alkenes include but-1-ene as well as cis-but-2-ene and trans-but-2-ene. The C present in the process of the present invention n-1 The alkenes may typically be conveyed from an olefin feed to the hydroformylation step, or may be formed at various stages throughout the process. The C present in the process of the present invention n-1 alkanes and C n-1 The amount of alkenes typically depends on the nature of the olefin feed in the hydroformylation step. Throughout the process of the present invention C n-1 alkanes and C n-1 Following the alkenes, other alkanes such as C n alkanes may also be present. In other words, a stream containing increased concentrations of C n-1 alkanes and C n-1 alkenes will also have increased concentrations of C n alkanes. Any C present in the process of the present invention n alkanes may be conveyed from the olefin feed to the hydroformylation step and / or may be produced during hydroformylation.

[0014] The amount of C n-1 alkene olefins in the olefin stream is not particularly limited and is not important for the present invention. For example, a suitable olefin stream to the hydroformylation reactor may contain at least 50 mol% C n-1 alkenes, optionally at least 60 mol% C n-1 alkenes, optionally at least 70 mol% C n-1 alkenes, optionally further at least 80 mol% C n-1 alkenes, and further optionally at least 90 mol% C n-1 alkenes, based on the total moles of the olefin stream.

[0015] The hydroformylation reactor may preferably be operated with a single pass conversion of at least 40%, optionally at least 50%, optionally further at least 60% of C n-1 alkenes. The C in the crude aldehyde stream nThe aldehyde concentration will depend on this conversion level and is not important to the present invention. The crude aldehyde stream contains, for example, at least 25 mol% C relative to the total moles of the crude aldehyde stream. n It may contain aldehydes.

[0016] The bottom flow from the crude aldehyde distillation column, which also supplies feed to the aldolization reactor, contains, for example, at least 70 mol% C relative to the total moles of the feed flow. n Aldehydes, and optionally at least 80 mol% C n Aldehydes, typically containing at least 90 mol% C n It may contain aldehydes.

[0017] The top flow from the crude aldehyde distillation column contains, for example, at least 95 mol% C relative to the total moles of the top flow from the crude aldehyde distillation column. n-1 Alkanes and C n-1 It may contain alkenes. This flow is transported as a liquid rather than a low-pressure gas, thereby recovering C n-1 Alkanes and C n-1 This can enhance the value of the Alken method.

[0018] The aldolization reaction involves at least 50%, optionally at least 60%, and optionally at least 70% C n This can be appropriately handled by single-pass transformation of aldehydes. C in crude aldol flow 2n The concentration of unsaturated aldehydes depends on this conversion level and is not important to the present invention. Typically, the crude aldol flow contains, for example, at least 5 mol% C relative to the total moles of the crude aldol flow. 2n It may contain unsaturated aldehydes. This stream may contain a large amount of water, for example, at least 50 mol% water relative to the total number of moles of the crude aldol stream. The crude aldol stream also contains heavy substances. As used herein, the term "heavy substances" means C 2n Molecular weight and / or carbon content greater than that of unsaturated aldehydes 2n This refers to organic molecules that have a higher boiling point than unsaturated aldehydes. Crude aldol flow is also C n-1Alkanes and C n-1 Unreacted C along with Alken n This would also include aldehydes.

[0019] The bottom flow from the crude aldol distillation column may contain an aqueous phase, for example, at least 80 mol% of the bottom flow may be aqueous. For example, when a homogeneous catalyst is used, the aqueous phase typically contains a dissolved aldolization catalyst, such as NaOH. The aqueous phase is typically decanted by C 2n It is separated from the organic phase containing the unsaturated aldehyde. Alternatively, for example, if a heterogeneous catalyst is used in the aldolization reaction and the entire bottom flow is the organic phase, there may be no aqueous phase to separate. The organic phase is C as described herein. 2n The present invention provides a feed for a method of producing alcohol. The method is carried out according to the present invention. 2n To produce unsaturated aldehydes, and then to supply the organic phase from the bottom flow of the crude aldol distillation column to the hydrogenation zone, C 2n This causes hydrogenation of unsaturated aldehydes, C 2n This includes the step of serving alcohol (vii).

[0020] The top flow from the crude aldol distillation column contains, for example, at least 15 mol% of combined C relative to the total moles of the top flow from the crude aldol distillation column. n-1 Alkane, C n-1 Alkenes and unreacted C n It may contain aldehydes. The top flow from the crude aldol distillation column may contain at least 50 mol% water relative to the total moles of the top flow from the crude aldol distillation column. The top flow from the crude aldol distillation column may contain at least 10 mol% unreacted C relative to the total moles of the top flow from the crude aldol distillation column. n It may contain aldehydes. The top flow from the crude aldol distillation column also contains a small amount of C. 2n Unsaturated aldehydes, e.g., less than 2 mol%, typically less than 1 mol% C 2n It may contain unsaturated aldehydes.

[0021] The first condenser zone typically uses a heat exchanger to condense the top flow from the first condenser zone. Preferably, at least a portion (i.e., not all), or substantially all, of the first condensate flow is recovered as a first condensate recirculation flow and returned to the aldolization reactor. The first condensate flow typically contains water, and the first condensate flow typically passes through a decanter to remove the water before being returned to the aldolization reactor. In the decanter, the aqueous solution flow is separated from the first condensate flow to provide the first condensate recirculation flow. The aqueous solution flow typically contains at least 95 mol% water relative to the total moles of the aqueous solution flow. After passing through the decanter, the first condensate recirculation flow contains, for example, at least 60 mol% combined C relative to the total moles of the first condensate flow. n-1 Alkane, C n-1 Alkenes and unreacted C n Aldehydes, optionally, in combination of at least 80 mol% C n-1 Alkane, C n-1 Alkenes and unreacted C n Aldehydes, and optionally, less than 5 mol% water relative to the total moles of the first condensate. The first condensate also contains any small residual amounts of C 2n It may contain unsaturated aldehydes.

[0022] The top flow from the first condenser zone is typically, for example, composed of at least 50 mol% of combined C relative to the total moles of the top flow from the first condenser zone. n-1 Alkane, C n-1 Alkenes and unreacted C n It may contain aldehydes. The top flow from the first condenser zone may contain, for example, at least 10 mol% C relative to the total moles of the top flow from the first condenser zone. n It may contain aldehydes. The top flow from the first condenser zone may also contain residual water.

[0023] In the second condenser zone, C n / C n-1The condensate may be produced in a single condensation step or in multiple condensation steps. In each condensation step, or in a condensation step, the top flow from the first condenser zone may be condensed using a heat exchanger. Alternatively, or further, in each condensation step, or in a condensation step, the top flow from the first condenser zone may be condensed by washing with a process flow that is colder than the top flow from the first condenser zone. Such a process flow may be actively cooled to a lower temperature than the top flow from the first condenser zone, if necessary. A suitable process flow is at least a portion of the first condensate recirculation flow. In this case, the remainder of the first condensate recirculation flow may still be returned to the aldolization reactor. Another suitable process flow is a portion of the crude aldehyde flow. In this case, the remainder of the crude aldehyde flow is still supplied to the crude aldehyde distillation zone. Another suitable process flow is a portion of the bottom flow from the crude aldehyde distillation column. In this case, the remainder of the bottom flow from the crude aldehyde distillation column is still supplied to the aldolization reactor. Such cleaning removes any residual C n Further improve aldehyde recovery to increase raw material efficiency.

[0024] A portion (i.e., not all) or substantially all of the top flow from the first condenser zone can be condensed. In an alternative method where not all of the flow is condensed, a vapor flow is generated by the second condenser zone, which can be discharged. This vapor flow has an increased concentration of C compared to the top flow from the first condenser zone. n-1 Alkanes and C n-1 It contains alkenes appropriately. This vapor stream contains, for example, at least 90 mol% C relative to the total moles of the vapor stream. n-1 Alkanes and C n-1 Alkenes, optionally containing at least 95 mol% C n-1 Alkanes and C n-1 May contain alkenes. n / C n-1 At least a portion (i.e., not all) or substantially all of the condensate is recovered and returned to or upstream of the crude aldehyde distillation column. n / C n-1Condensates are typically, for example, C n / C n-1 A combination of C in an amount of at least 50 mol% relative to the total moles of the condensate. n-1 Alkane, C n-1 Alkenes, and C n May contain aldehydes. C n / C n-1 Condensates are, for example, C n / C n-1 At least 15 mol% of C relative to the total moles of the condensate n May contain aldehydes. C n / C n-1 The condensate may also contain residual water. In that case, the water can be removed using a decanter. In the decanter, the aqueous solution stream is C n / C n-1 It is separated from the condensate. Typically, C n / C n-1 At least 20 mol%, optionally at least 50 mol%, and optionally at least 90 mol% of the condensate are recovered as a recirculating flow. Typically, C n / C n-1 At least 95 mol% of the condensate is returned to or upstream of the crude aldehyde distillation column. Advantageously, this recirculation can be carried out without the costly compression that would normally be required because the crude aldol distillation column typically operates at lower pressures than the crude aldehyde distillation column, since the recirculation is provided as a liquid.

[0025] The temperature of the first condenser zone is typically higher than the condensation temperature of the second condenser zone, for example, by at least 10°C. The temperature of the first condenser zone is typically 50°C to 110°C, and optionally 70°C to 90°C. The condensation temperature in the second condenser zone is typically 2°C to 50°C, optionally 35°C to 45°C, and optionally 35°C to 40°C.

[0026] According to a second aspect of the present invention, C 2n An apparatus for producing unsaturated aldehydes (wherein n is in the range of 3 to 6), A hydroformylation reactor is used to bring an olefin stream containing an alkene into contact with hydrogen and carbon monoxide to produce a hydroformylation reaction with the alkene, C n Aldehyde, C n-1 Alkanes, and C n-1 A hydroformylation reactor configured to provide a feed stream containing alkenes, A crude aldehyde distillation column, configured to receive a crude aldehyde stream and provide top and bottom flows, An aldolation reactor is configured to receive a bottom flow from a crude aldehyde distillation column and provide a crude aldol flow, from which the crude aldol flow produces the aldol product C 2n Unsaturated aldehyde, unreacted C n Aldehyde, C n-1 Alkane, C n-1 An aldol reactor containing alkenes, water, and heavy substances, A crude aldol distillation column, configured to receive a crude aldol flow and provide a top flow and a bottom flow, A first condenser zone, configured to cool the first top flow and provide the first condensed flow and top flow, A second condenser zone, which is in fluid communication with the first condenser zone and is configured to cool the first top flow and provide condensate and optionally a vapor flow, is provided. The second condenser zone is in fluid communication with the crude aldehyde distillation column or the upstream of the crude aldehyde distillation column, and returns at least a portion of the condensate to the upstream of the crude aldehyde distillation column or the crude aldehyde distillation column. An apparatus is provided in which a first condenser zone is optionally fluid-connected to an aldolization reactor to return at least a portion of the first condensation flow to the aldolization reactor. [Brief explanation of the drawing]

[0027] [Figure 1] This is a schematic diagram of a conventional process for the industrial production of aldehydes. [Figure 2] This figure shows a schematic process for the industrial production of aldehydes according to the present invention. [Figure 3] This figure shows a schematic process for the industrial production of aldehydes according to the present invention. [Figure 4] This figure shows a schematic process for the industrial production of aldehydes according to the present invention. [Modes for carrying out the invention]

[0028] The present invention will now be described in detail with reference to the following non-limiting examples and accompanying drawings. Although the present invention is generally described with respect to the production of 2-propylhepta-2-enal, those skilled in the art will see that the present invention may be used for any other C 2n You will understand that this can be applied to the production of unsaturated aldehydes.

[0029] The 2-alkyl alkanols described herein are preferably formed via the hydrogenation of an α,β-unsaturated aldehyde, the α,β-unsaturated aldehyde being a self-condensation product. Preferably, the α,β-unsaturated aldehyde is a self-condensation product of pentanal. Preferably, the α,β-unsaturated aldehyde is 2-propylhepta-2-enal.

[0030] The following scheme 1 illustrates a general process for the production of 2-propylhepta-2-enal and 2-propylheptanol.

[0031] [ka]

[0032] Here, the manufacturing processes for 2-propylhepta-2-enal and 2-propylheptanol will be described with reference to Scheme 1 and Figure 1 above.

[0033] Referring to Figure 1, C n-1 Alkenes, such as buto-1-ene, and C n-1Alkanes, for example, isomers of butane, and C n-1 An olefin stream 1 containing alkenes, such as buto-1-ene, cis-buto-2-ene, and trans-buto-2-ene, is supplied to the hydroformylation reactor 5. The olefin stream 1 may be provided as a crude decomposition product stream from the industrial decomposition of hydrocarbons. Those skilled in the art will be familiar with the industrial decomposition process. The crude decomposition product stream is, for example, provided to the hydroformylation reactor 5 by passing the crude decomposition product stream through one or more distillation columns and C in the olefin stream 1. n-1 The concentration of the alkene may be increased through one or more enrichment steps.

[0034] In the hydroformylation reactor 5, C n-1 The alkene is brought into contact with carbon monoxide and hydrogen provided through synthesis gas flow 3 in the presence of a liquid catalyst solution, C n The present invention provides aldehydes, more specifically pentanal. This hydroformylation process is also known as the "oxo process." Typical flow sheets are described, for example, in U.S. Patent No. 4,148,830 or No. 5,087,763, which are incorporated herein by reference. The hydroformylation liquid catalyst system typically comprises a solvent, rhodium, ligands and other components, but may be any catalyst system suitable for hydroformylation. Typical organophosphine and organophosphine ligands are described, for example, in International Publication Nos. 2008 / 115740, 2011 / 087690, 2010 / 117391 and 2016 / 089602, which are incorporated herein by reference.

[0035] Hydroformylation causes C n-1 Alkane, C n-1 Alkenes and C n A crude aldehyde stream 7 is obtained containing an aldehyde hydroformylation product, such as pentanal, and in the case of pentanal, a mixture of isomers 2-methylbutanal and 3-methylbutanal.

[0036] The crude aldehyde stream 7 is sent to the crude aldehyde distillation zone 9 and supplied to the aldolization reactor 15, containing C in the aldolization reactor feed stream 13. n Increase the aldehyde concentration. Distillation zone 9 may be a single distillation column or a distillation apparatus with multiple columns, however, C should be used relative to the crude aldehyde flow. n C n Aldehyde, C n-1 Alkanes, and C n-1 The tower bottom flow 13 containing alkenes is C compared to the crude aldehyde flow. n-1 Alkanes, and C n-1 The condition is that it is produced along with the top flow 11 of the tower, where the concentration of alkenes increases. Flow 11 is transported out as a liquid rather than a low-pressure gas, and thereby C is recovered. n-1 Alkanes and C n-1 This can increase the value of the alkene flow. Furthermore, a portion of the flow can be recycled for hydroformylation, resulting in further C n It can convert aldehydes.

[0037] Any suitable means can be used in the distillation zone, and those skilled in the art can determine, for example, which column interior to use and the conditions appropriate for the desired separation. A further concentration step may be included between the crude aldehyde distillation column 9 and the aldolization reactor 15, but is not required. For example, a distillation column to increase the amount of linear aldehyde.

[0038] Flow 13 is supplied to the aldolization reactor 15. The aldolization reaction is carried out in the aldolization reactor 15 under condensation and dehydration conditions, C n This reaction produces an aldolation of an aldehyde, such as pentanal, and unreacted C n Aldehyde, C n-1 Alkane, C n-1 Alkenes, water, and heavy substances together, aldol product C 2n The present invention provides a crude aldol stream containing an unsaturated aldehyde, such as 2-propylhepta-2-enal. The heavy substance includes trace amounts of aldolization reaction catalysts, such as sodium hydroxide, and salts, such as sodium valerate.

[0039] Such aldolization processes are known in the art and are described, for example, in U.S. Patents 5,434,313 and 6,340,778, which are incorporated herein by reference. Suitable reagents for carrying out the aldolization reaction in the aldolization reactor 15 include suitable bases or acids. The aldolization reaction is preferably carried out in the liquid phase, i.e., in the feedstock, and the reagents are in the liquid phase. Those skilled in the art will know of suitable acids and bases for liquid-phase reactions, but can be selected from inorganic bases (e.g., NaOH), organic bases (e.g., NET3), inorganic acids (e.g., H2SO4), and organic acids (e.g., F3CCOOH). Alternatively, heterogeneous catalysts may be used, and those skilled in the art will recognize suitable such catalysts. During the aldolization reaction, water is produced as a byproduct (dehydration). To carry out the aldolization reaction, the aldolization reactor 15 is typically maintained at a temperature of 80°C to 140°C. Those skilled in the art will know n To achieve the desired single-pass conversion of an aldehyde, suitable conditions for manipulating the aldolization reaction can be determined.

[0040] The aldolization reaction is C 2n Unsaturated aldehyde, e.g., 2-propylhepta-2-enal, unreacted C n Aldehyde, C n-1 Alkane, C n-1 A crude aldol stream 17 containing alkenes, water, and heavy substances is provided. The aldolization reaction is typically operated continuously so that the crude aldol stream 17 is removed from the aldolization reactor 15 during the aldolization reaction.

[0041] The crude aldol stream 17 undergoes a concentration process by sending the crude aldol stream 17 to the crude aldol distillation column 19, and the organic phase is supplied to a hydrogenation reactor (not shown) C 2n In the bottom flow 21 of the tower, water can be decanted to remove it before producing an alcohol, such as 2-propylheptanol. 2n Increase the concentration of unsaturated aldehydes.

[0042] More specifically, the aldol distillation process involves passing the crude aldol stream 17 through a crude aldol distillation column 19, which is operated under distillation conditions, to obtain a C24 stream with increased concentration compared to the crude aldol stream 17. 2n The bottom flow 21 of the tower contains unsaturated aldehydes, water, and heavy substances, as well as unreacted C n Aldehyde, C n-1 Alkane, C n-1 Alkenes and the reduced concentration of C compared to crude aldol stream 9 2n This involves forming a top flow 23 containing unsaturated aldehydes, water, and heavy substances. Any suitable means may be used for distillation, and those skilled in the art can determine, for example, which column interiors to use and the conditions suitable for the desired separation. Distillation is described, for example, in U.S. Patent No. 5,434,313, which is incorporated herein by reference.

[0043] Figure 1 shows a crude aldol distillation column 19 included in a conventional industrial process for producing 2-propylhepta-2-enal. The top flow 23 has an increased concentration of C compared to the top flow 23. n A condensed flow 29 containing aldehydes and water, and mainly C n-1 Alkanes and C n-1 The vapor stream 27 containing alkenes is sent to a condenser zone 25 configured to provide a condenser stream 29. n-1 Alkanes and C n-1 Alkenes, and any C present in the first tower top flow 2n It contains unsaturated aldehydes. The condenser zone 25 is equipped with a heat exchanger to cool the top flow 23 to a temperature of 70°C to 90°C, preferably about 80°C, especially when producing 2-propylhepta-2-enal from pentanal. This flow 29 passes through a decanter 31, which separates the aqueous flow 33 from the recirculation flow 35, and the recirculation flow 35 recirculates the organic matter to the aldolization reactor 15. To mitigate the pressure rise in the crude aldol distillation column 19, the vapor flow 27 is simply purged during the distillation process. The vapor flow 27 is typically some C n Aldehydes, and C n-1 Alkanes and C n-1It contains an alkene, and in this way, C n Aldehydes are removed from the process during purging.

[0044] Figure 2 is a schematic diagram of the method according to the present invention, in which a first condenser zone 25 and a second condenser zone 37 are located at the top of a crude aldol distillation column.

[0045] The first condenser zone 25 comprises a first heat exchanger. The top flow 23 from the crude aldol distillation column is cooled in the heat exchanger, for example, by a flow of cold water. At least a portion of the first condensed flow 29 is decanted according to the method shown in Figure 1 and recycled to the aldolization reactor 15. Typically, the first top flow 23 is cooled in the heat exchanger 25 to a temperature of 70°C to 90°C, preferably about 80°C, especially when producing 2-propylhepta-2-enal from pentanal.

[0046] Instead of being discharged according to the conventional process shown in Figure 1, the top flow 27 from the first condenser zone is sent to the second condenser zone 37. The second condenser zone receives C with increased concentration compared to the second top flow 27. n Aldehydes, such as pentanal, containing C n / C n-1 It is configured to provide condensing flow 41. Optionally, an increased concentration of C is provided compared to the second top flow 27. n-1 Alkanes and C n-1 A vapor stream 39 is also provided that contains an alkene, such as an isomer of butane, together with buto-1-ene, cis-buto-2-ene, and trans-buto-2-ene.

[0047] The second condenser zone is C n / C n-1 A heat exchanger is provided to provide a condensing flow 41. The second top flow 27 is cooled in the second heat exchanger, typically by a chilled water flow. Preferably, the second top flow 41 is cooled in the second heat exchanger 37 to about 2°C to 50°C, optionally 35°C to 45°C, and even more optionally 35°C to 40°C, for example, to about 38°C, especially when producing 2-propylhepta-2-enal from pentanal.n / C n-1 The condensate 41 passes through a decanter 43 that separates the aqueous solution stream 45 from the recirculation stream 47 that recirculates the organic matter back to the crude aldehyde distillation column 9. This distillation column is C n-1 Alkanes and C n-1 From Alken C n It is more effective in separating aldehydes and unreacted C n This facilitates efficient recycling of aldehydes, returning them to the aldolization process rather than discarding them for discharge. n-1 Alkanes and C n-1 Alkene recovery also allows the flow to be transported as a liquid rather than a low-pressure gas, thereby enabling the recovery of C n-1 Alkanes and C n-1 Increase the value of the Alken method.

[0048] Figure 3 is a schematic diagram of another method according to the present invention, in which a first condenser zone 25 and a second condenser zone 37 are present at the top of a crude aldol distillation column. In this method, the top flow 27 is washed with a recirculation flow 35 which is colder than the top flow 27, rather than a heat exchanger, and this flow is condensed to produce C n / C n-1 A condensation flow 41 is provided. The flow 41 passes through the decanter 43 to provide a recirculation flow 47, which recirculates the organic matter to the crude aldehyde distillation column 9. n-1 Alkanes and C n-1 The vapor stream 39 containing alkenes is optional.

[0049] Figure 4 is a schematic diagram of another method according to the present invention, in which a first condenser zone 25 and a second condenser zone 37 are present at the top of a crude aldol distillation column. In this method, instead of a heat exchanger, a portion of the crude aldehyde flow 7 is used to wash the top flow 27, and this flow is condensed to C n / C n-1 A condensing flow 41 is provided. If necessary, this washing flow is cooled in a cooling stage (not shown). Flow 41 passes through a decanter 43 to provide a recirculation flow 47, which recirculates the organic matter to the crude aldehyde distillation column 9. n-1Alkanes and C n-1 The vapor stream 39 containing alkenes is optional. A portion of the crude aldol stream 7 is further supplied to the crude aldehyde distillation zone 9.

[0050] Increased concentration of C 2n The bottom flow 21 from the crude aldol distillation column shown in Figures 1-4, containing an unsaturated aldehyde, such as 2-propylhepta-2-enal, can then be decanted to remove the aqueous phase, after which the organic phase can be fed into a hydrogenation reactor (not shown). Under hydrogenation conditions in the reactor in the presence of hydrogen and a catalyst, C 2n Unsaturated aldehydes undergo hydrogenation, C 2n Alcohols, such as 2-propylheptanol, are provided. Suitable hydrogenation processes are known in the art and are disclosed, for example, in International Publication No. 2018 / 069714, which is incorporated herein by reference. The hydrogenation reactor can be operated under any preferred conditions. Catalysts are generally used. Any suitable catalyst may be used. Generally, the active components of the catalyst are based on metals of groups 6 to 10. Preferred examples include copper, nickel, manganese, zinc, cobalt, palladium, ruthenium, and iron. The catalyst may be supported. Any suitable support can be used. Preferred supports include alumina, silica, or diatomaceous earth. Particularly preferred catalysts may be supported copper chromite catalysts. The catalyst may also include co-catalysts to improve selectivity.

[0051] Hydrogenation may be carried out in the liquid phase or the vapor phase. Any suitable configuration may be used, and the reactor can be operated under any suitable conditions. The specific conditions selected depend on the catalyst selected, but hydrogenation may be carried out at temperatures of about 100°C to about 200°C and pressures from atmospheric pressure to about 15 MPa.

[0052] When liquid-phase hydrogenation is used, it can be carried out in any preferred manner. In one configuration, it may be carried out as forward flow on a packed catalyst bed. To remove the heat of the reaction, a large-scale recirculation of the cooled product may be mixed with the feed. An example of a preferred method is described in British Patent No. 1362071, incorporated herein by reference. In an alternative configuration, one or more heat exchangers may be used to remove the heat of the reaction.

[0053] C 2n A crude alcohol stream containing an alcohol, such as 2-propylheptanol, can then be purified by one or more purification steps to provide a purified alcohol stream. For example, the crude alcohol stream may undergo one or more distillation and finishing steps, as described, for example, in International Publication No. 2018 / 069714. [Examples]

[0054] The following examples demonstrate that the method and apparatus according to the present invention enable significant recovery of unreacted C5 aldehydes that would ordinarily be discarded. The following examples utilize a computational model of the system schematically shown in Figure 2, using the AVEVA PRO II simulator and known properties (e.g., boiling point, density, etc.) of known components in each stream (e.g., water, butene, pentanal), as well as vapor-liquid equilibrium data. The data are used with the method and apparatus of the present invention to recover C n / C n-1 This demonstrates that a significant amount of useful small organic molecules can be recovered from condensed logistics 41.

[0055] The results of the simulation analysis are shown in the table below.

[0056] [Table 1] * Average molecular weight of the flow based on the mole percentage of components in the related flow

[0057] These data show that the apparatus in Figure 3 advantageously enables significant recovery of C5 aldehydes, which can be recycled back into the crude aldehyde distillation column and re-entered into the aldolization reaction, along with the simultaneous separation and recovery of C4 alkanes and alkenes. As indicated by the mass flow rate, the majority of the composition of the top flow 27 in conventional methods is obtained using the method of the present invention, C n / C n-1 It is recovered as recyclable organic matter in the condensed logistics 41.

[0058] The apparatus in Figure 2 is calculated to yield approximately 1% more 2-propylheptanol after hydrogenation of the produced 2-propyl(proyl)hepta-2-enal compared to the apparatus in Figure 1.

[0059] The table below shows that the temperature of the second heat exchanger in the method and apparatus of the present invention is C n / C n-1 This shows the effect of condensation flow rate 41 on the mass flow rate.

[0060] [Table 2]

Claims

1. C ２ｎ A method for producing an unsaturated aldehyde (wherein n is in the range of 3 or more and 6 or less), (i) C ｎ－１ An olefin stream containing alkenes is supplied to a hydroformylation reactor, and the olefin stream is brought into contact with a hydroformylation gas stream containing hydrogen and carbon monoxide to produce a hydroformylation reaction, C ｎ Aldehyde, C ｎ－１ Alkanes and C ｎ－１ To provide a crude aldehyde stream containing alkenes, (ii) feeding the crude aldehyde stream to a crude aldehyde distillation zone operated under distillation conditions to form a bottoms stream comprising the C ｎ aldehyde, the C ｎ－１ alkane, and the C ｎ－１ alkene, and having an increased concentration of the C ｎ aldehyde relative to the crude aldehyde stream, and a tops stream comprising an increased concentration of C ｎ－１ alkane and C ｎ－１ alkene relative to the crude aldehyde stream; (iii) The bottom flow from the crude aldehyde distillation column is supplied to the aldolization reactor under condensation and dehydration conditions, and the C ｎ This reaction produces the aldolization of an aldehyde, resulting in the aldol product C. ２ｎ Unsaturated aldehyde, unreacted C ｎ Aldehyde, C ｎ－１ Alkane, C ｎ－１ To provide a crude aldol flow containing alkenes, water, and heavy substances, (iv) The crude aldol stream is passed through a crude aldol distillation column operated under distillation conditions to obtain the increased concentration of C compared to the crude aldol stream. ２ｎ A bottom flow containing an unsaturated aldehyde, the water and the heavy substance, and unreacted C ｎ Aldehyde, C ｎ－１ Alkane, C ｎ－１ Alkenes, and the C at a reduced concentration compared to the crude aldol flow. ２ｎ To form a top flow containing an unsaturated aldehyde, the water and the heavy substance, (v) The top flow from the crude aldol distillation column is in the first condenser zone and has an increased concentration of unreacted C compared to the top flow from the crude aldol distillation column. ｎ A first condensation flow containing aldehydes and water, and C ｎ－１ Alkane, C ｎ－１ Alkenes and unreacted C, which has decreased in concentration compared to the top flow from the crude aldol distillation column. ｎ It is configured to pass through a first condenser zone that provides a top flow containing aldehydes and water, (vi) The top flow from the first condenser zone is condensed in the second condenser zone, which condenses at least a portion of the top flow from the first condenser zone, C ｎ / C ｎ－１ This includes passing the material through a second condenser zone configured to provide condensates, Said C ｎ / C ｎ－１ A method wherein at least a portion of the condensate is recovered and returned to the upstream of the crude aldehyde distillation column or to the crude aldehyde distillation column.

2. The method according to claim 1, wherein at least a portion of the first condensation flow is recovered as a first condensation flow recirculation flow and returned to the aldolization reactor.

3. The method according to claim 1 or 2, wherein the second condenser zone is configured to condense substantially all of the top flow from the first condenser zone.

4. The method according to any one of claims 1 to 3, wherein at least a portion of the top flow from the first condenser zone is condensed by washing with a process flow.

5. The method according to any one of claims 1 to 4, wherein at least a portion of the top flow from the first condenser zone is condensed using a heat exchanger.

6. The method according to any one of claims 1 to 5, wherein the temperature of the first condenser zone is higher than the condensation temperature of the second condenser zone.

7. The method according to any one of claims 1 to 6, wherein n is 3, 4, or 5.

8. Said C ２ｎ The method according to claim 7, wherein the unsaturated aldehyde is a 2-alkyl alkenal.

9. Said C ２ｎ The method according to claim 8, wherein the unsaturated aldehyde is 2-propylhepta-2-enal.

10. Said C ｎ The method according to any one of claims 1 to 9, wherein the aldehyde is pentanal.

11. The crude aldehyde distillation zone includes a single crude aldehyde distillation column, and the single crude aldehyde distillation column is operated under distillation conditions, C ｎ Aldehyde, C ｎ－１ Alkanes and C ｎ－１ The C2 is contained in an alkene and has an increased concentration relative to the crude aldehyde stream. ｎ The bottom flow containing aldehydes and the C with increased concentration compared to the crude aldehyde flow. ｎ－１ Alkanes and C ｎ－１ The method according to any one of claims 1 to 10, for forming a tower top flow containing an alkene.

12. C ２ｎ A method for producing alcohol, wherein C is produced according to the method according to any one of claims 1 to 11. ２ｎ An unsaturated aldehyde is produced, and then the organic phase from the bottom flow of the crude aldol distillation column is supplied to the hydrogenation zone, C ２ｎ This causes hydrogenation of unsaturated aldehydes, C ２ｎ A method comprising the step (vii) of providing alcohol.

13. C ２ｎ An apparatus for producing unsaturated aldehydes (wherein n is in the range of 3 to 6), A hydroformylation reactor is provided, wherein an olefin stream containing an alkene is brought into contact with hydrogen and carbon monoxide to produce a hydroformylation reaction with the alkene, C ｎ Aldehyde, C ｎ－１ Alkanes and C ｎ－１ A hydroformylation reactor configured to provide a feed stream containing alkenes, A crude aldehyde distillation column, configured to receive the crude aldehyde flow and provide top and bottom flows, An aldolation reactor is configured to receive the bottom flow from the crude aldehyde distillation column and provide a crude aldol flow, wherein the crude aldol flow produces the aldol product C ２ｎ Unsaturated aldehyde, unreacted C ｎ Aldehyde, C ｎ－１ Alkane, C ｎ－１ An aldol reactor containing alkenes, water, and heavy substances, A crude aldol distillation column, configured to receive the crude aldol flow and provide top and bottom flows, A first condenser zone, configured to cool the first top flow and provide the first condensed flow and top flow, A second condenser zone, which is in fluid communication with the first condenser zone and is configured to cool the first top flow of the tower and provide condensate and optionally a vapor flow, is provided. The second condenser zone is in fluid communication with the crude aldehyde distillation column or the upstream of the crude aldehyde distillation column, and returns at least a portion of the condensate to the crude aldehyde distillation column or the upstream of the crude aldehyde distillation column. An apparatus wherein the first condenser zone is optionally in fluid communication with the aldol reactor, and at least a portion of the first condensation flow is returned to the aldol reactor.

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