Methods for the production of a C2N unsaturated aldehyde and a C2N alcohol, and apparatus for the production of a C2N unsaturated aldehyde.

Description

24 Methods for the production of a C2n unsaturated aldehyde and a C2n alcohol, and apparatus for the production of a C2n unsaturated aldehyde. FIELD OF THE INVENTION

[001] The present invention relates to a method and apparatus for the production of aldehydes. In particular, the methods and apparatus according to the present invention provide improved raw material efficiency in the production of synthetic aldehydes, more particularly 2-alkylalkenals. BACKGROUND

[002] Synthetic aldehydes, such as 2-alkylalkenals, are generally used as intermediates in the production of alcohols, such as 2-alkylalkanols, which are used in a wide variety of applications in the chemical industries, including as solvents, fuels, chemical intermediates in the synthesis of organic compounds, and the like. Globally, a wide variety of alcohols are produced each year. For certain alcohols, for example, ethanol, biosynthetic methods, such as fermentation, may be suitable for alcohol production. However, for longer-chain and branched-chain alcohols, synthetic production is generally necessary.

[003] Existing methods for the synthetic production of aldehydes such as 2-alkylalkenals include the hydroformylation step of olefins in the presence of a catalyst (also called the 'Oxo' process), followed by an aldolization reaction. Hydroformylation introduces a formyl group into the unsaturated olefin to provide an aldehyde.Hydroformylation can be carried out by bringing the olefin into contact with synthesis gas, a mixture of carbon monoxide and hydrogen. Once the aldehyde has been produced, hydrogenation reduces the aldehyde to give the corresponding alcohol.

[004] When longer-chain or branched-chain alcohols are required, the process may include an aldolization step to condense two aldehydes, followed by dehydration, thus providing Petition 870260074513, dated 07 / 27 / 2026, page 10 / 33 / 24 an unsaturated aldehyde, such as a 2-alkylalkenal. Such aldolization reaction products are typically called α,β-unsaturated aldehydes. When the aldolization reaction occurs between two identical aldehydes, the α,β-unsaturated aldehyde is called a self-condensation product. When the aldolization reaction occurs between two different aldehydes, the α,β-unsaturated aldehyde is called a cross-condensation product. The aldolization process is typically catalyzed by a base or an acid.

[005] The unsaturated aldehyde is then subsequently reduced by hydrogenation to give the corresponding saturated alcohol.

[006] Given the wide utility of alcohols, particularly 2-alkylalkanols, it is desirable to produce alcohols in an economical way, on an industrial scale with maximum yield and maximum purity.

[007] It is therefore an objective of the present invention to improve the efficiency of the raw material and the yield in the preparation of aldehydes, particularly 2-alkylalkenols, produced by industrial processes. This advantage is a benefit in itself and also a benefit to the overall efficiency of the raw material and the yield in the production of alcohols, particularly 2-alkylalkanols, in which aldehydes are an intermediate. SUMMARY OF THE INVENTION

[008] The inventors provide a new method and apparatus for the production of an unsaturated aldehyde C2n from an aldehyde Cn, wherein n is in the range of, inclusive, 3 to 6, by means of an aldolization reaction, more particularly 2-alkylalkenals and even more particularly 2-propyl hept-2enal. Advantageously, the method and apparatus of the present invention increase the yield of the product and increase the efficiency of the raw material.

[009] The method and apparatus of the present invention enable enhanced recovery of unreacted Cn aldehyde from a crude aldol distillation column supplied after the aldolization reaction. The distillation column is configured to separate the reaction mixture supplied by the step Petition 870260074513, dated 07 / 27 / 2026, p. 11 / 33 / 24 of aldolization. More particularly, the present invention provides a first condenser zone and a second condenser zone above the distillation column to recover a first condensed stream comprising unreacted Cn aldehyde, a Cn / Cn-1 condensate comprising the remaining unreacted Cn aldehyde together with Cn-1 alkane(s) and Cn-1 alkene(s), and an optional vapor stream comprising Cn-1 alkane(s) and Cn-1 alkenes. The Cn-1 alkane(s) and Cn-1 alkene(s) are typically present in the Cn aldehyde feed stream for the aldolization reaction because they are present in the feed stream for the hydroformylation reaction.A small amount of Cn-1 alkane(s) and Cn-1 alkene(s) is typically allowed to pass through to the aldolization reaction to moderate the temperature at the base of a crude aldehyde distillation column described in this document and used to at least partially separate the Cn-1 alkane(s) and Cn-1 alkene(s) from the Cn aldehyde. The Cn aldehyde, Cn-1 alkane(s), and Cn-1 alkene(s) accumulate at the top of the aldol distillation column and concentrate to a high degree due to their hydrophobic nature, and are conventionally vented to limit their accumulation. Typically, this was achieved by partially condensing the top vapors of the crude aldol distillation column in a single condensation step, for example, by cooling to about 80 °C in the case of pentanal used in the synthesis of 2-propyl hept-2-enal. This leads to the loss of Cn aldehyde feedstock from the process.

[0010] According to a first aspect of the invention, a method is provided for the production of an unsaturated aldehyde C2n, wherein n is in the range of, inclusive, 3 to 6, the method comprising: (i) feeding an olefin stream comprising a Cn-1 alkene to a hydroformylation reactor and contacting the olefin stream with a hydroformylation gas stream comprising hydrogen and carbon monoxide to effect a hydroformylation reaction to provide Petition 870260074513, dated 07 / 27 / 2026, page 12 / 33 / 24 a crude aldehyde stream comprising a Cn aldehyde, Cn-i alkane(s) and Cn-i alkene(s); (ii) feeding the crude aldehyde stream into a crude aldehyde distillation zone operated under distillation conditions to form a bottom stream comprising Cn aldehyde, Cn-i alkane(s) and Cn-i alkene(s) and comprising an increased concentration of Cn aldehyde relative to the crude aldehyde stream and a top vapor stream comprising an increased concentration of Cn-i alkane(s) relative to the crude aldehyde stream; (iii) feeding the bottom stream from the crude aldehyde distillation column to an aldolization reactor under condensation and dehydration conditions to effect an aldolization reaction of Cn aldehyde to provide a crude aldol stream comprising an unsaturated aldehyde C2n aldol product, unreacted aldehyde Cn, alkane(s) Cn-i, alkene(s) Cn-i, water and heavy; (iv) pass the crude aldol stream to a crude aldol distillation column operated under distillation conditions to form a bottom stream having an increased concentration of unsaturated aldehyde C2n, water and heavys compared to the crude aldol stream and a top vapor stream comprising unreacted aldehyde Cn, alkane(s) Cn-i, alkene(s) Cn-i and a reduced concentration of unsaturated aldehyde C2n, water and heavys compared to the crude aldol stream; (v) move the top vapor stream from the crude aldol distillation column to a first condenser zone, the first condenser zone being configured to provide a first condensed stream comprising an increased concentration of unreacted aldehyde Cn and water compared to the top vapor stream from the crude aldol distillation column, and a top vapor stream comprising Cn-i alkane(s), Cn-i alkene(s) and a reduced concentration of unreacted aldehyde Cn and water Petition 870260074513, dated 07 / 27 / 2026, p. 13 / 33 / 24 in comparison with the top vapor stream of the crude aldol distillation column; (vi) passing the top vapor stream from the first condenser zone to a second condenser zone, the second condenser zone being configured to condense at least a portion of the top vapor stream from the first condenser zone to provide the Cn / Cn-1 condensate; and at least a portion of the Cn / Cn-1 condensate being recovered and returned upstream of the crude aldehyde distillation column or to the crude aldehyde distillation column.

[0011] Advantageously, the crude aldehyde distillation zone is more effective at separating Cn aldehyde from Cn-1 alkane(s) and Cn-1 alkene(s) and facilitates the efficient recycling of unreacted Cn aldehyde back to the aldolization step instead of wasting it on venting release. The recovery of Cn-1 alkane(s) and Cn-1 alkene(s) in the crude aldehyde distillation zone further enables the stream to be exported as a liquid instead of a low-pressure gas, thus increasing the value of the recovered Cn-1 alkane(s) and Cn-1 alkene(s) stream(s).

[0012] In the method of the invention, n is suitably 4, 5 or 6, typically 4 or 5, preferably 5. Consequently, the alkene Cn-1 in the olefin feed stream may suitably be propene or butene, preferably butene, for example but-1-ene. The aldehyde Cn is suitably a C4, C5 or C6 aldehyde, typically C4 or C5, preferably C5, i.e. pentanal. Most of the aldehyde Cn undergoing the aldolization reaction to provide the unsaturated aldol product aldehyde C2n is a linear aldehyde, for example, valeraldehyde (pentanal). Typically, the branched aldehyde will be present in an amount of at most 10 mol%, suitably at most 7.5 mol%, of the total aldehyde Cn. For example, 3-methylbutanal and 2-methylbutanal may be present where the aldehyde Cn is Petition 870260074513, dated 07 / 27 / 2026, page 14 / 33 / 24 pentanal. Such isomers can typically be generated during the hydroformylation step. The unsaturated aldehyde C2n is suitably an unsaturated aldehyde Cg, C10 or C12, typically an unsaturated aldehyde C8 or C10, preferably C10. The unsaturated aldehyde C2n can be a 2-alkylalcenal. Preferably, the aldehyde C2n is 2-propyl hept-2-enal.

[0013] The Cn-1 alkane(s) may be a Cn-1 alkane or a mixture of isomeric Cn-1 alkanes. For example, in the preferred embodiment where n is 5 and the Cn aldehyde is pentanal, the Cn-1 alkane(s) include n-butane and i-butane, typically n-butane. The Cn-1 alkane(s) present in the method of the invention may be transported from the olefin feed stream to the hydroformylation step and / or may be produced during hydroformylation. The Cn-1 alkene(s) may be a Cn-1 alkene or a mixture of isomeric Cn-1 alkenes. For example, in the preferred aspect where n is 5 and the aldehyde Cn is pentanal, the Cn-1 alkene(s) include(s) but-1-ene and cis- and trans-but-2-ene. The CN-1 alkenes present in the method of the invention are typically transported from the olefin feed stream to the hydroformylation step and may also form at various stages throughout the process.The amount of Cn-1 alkane(s) and Cn-1 alkene(s) present in the method of the invention will typically depend on the nature of the olefin feed stream in the hydroformylation step. Other alkane(s), such as Cn alkane(s), may also be present, which will follow the Cn-1 alkane(s) and Cn-1 alkene(s) throughout the process of the invention. In other words, a stream comprising an increased concentration of Cn-1 alkane(s) and Cn-1 alkene(s) will also have an increased concentration of Cn alkane(s). Any Cn alkane(s) present in the method of the invention may be transported from the olefin feed stream to the hydroformylation step and / or may be produced during hydroformylation.

[0014] The amount of Cn-1 olefin alkene in the olefin stream is not particularly limited and is not of critical importance to the invention. Petition 870260074513, dated 07 / 27 / 2026, p. 15 / 33 / 24 example, a suitable olefin stream for the hydroformylation reactor may comprise at least 50%, by mole, of the alkene Cn-1, optionally at least 60%, by mole, of the alkene Cn-1, optionally at least 70%, by mole, of the alkene Cn-1, optionally at least 80%, by mole, of the alkene Cn-1, optionally at least 90%, by mole, of the alkene Cn-1, relative to the total moles of the olefin stream.

[0015] The hydroformylation reactor can be suitably operated at a single-pass conversion of the alkene Cn-1 of at least 40%, optionally at least 50%, and optionally at least 60%. The concentration of aldehyde Cn in the crude aldehyde stream will depend on this conversion level and is not of critical importance to the invention. The crude aldehyde stream may comprise, for example, at least 25%, by mole, of aldehyde Cn relative to the total moles of the crude aldehyde stream.

[0016] The bottom stream of the crude aldehyde distillation column, which also provides the feed stream to the aldolization reactor, may comprise, for example, at least 70 mol% of Cn aldehyde, optionally at least 80 mol% of Cn aldehyde, typically at least 90 mol% of Cn aldehyde relative to the total moles of the feed stream.

[0017] The top vapor stream from the crude aldehyde distillation column may comprise, for example, at least 95%, by mole, of Cn-1 alkane(s) and Cn-1 alkene(s) relative to the total moles of the top vapor stream from the crude aldehyde distillation column. This stream may be exported as a liquid instead of a low-pressure gas, thereby increasing the value of the recovered Cn-1 alkane(s) and Cn-1 alkene(s) stream(s).

[0018] The aldolization reaction can be suitably operated to a single-pass conversion of the aldehyde Cn of at least 50%, optionally at least 60%, and optionally at least 70%. The concentration of unsaturated aldehyde C2n in the crude aldol stream will depend on this level of conversion and Petition 870260074513, dated 27 / 07 / 2026, p. 16 / 33 / 24 is not of critical importance to the invention. Typically, the crude aldol stream may comprise, for example, at least 5%, by mole, of the unsaturated aldehyde C2n relative to the total moles of the crude aldol stream. A large amount of water may be present in this stream, for example, at least 50%, by mole, relative to the total moles of the crude aldol stream. The crude aldol stream will also comprise heavy molecules. As used herein, the term heavy molecules refers to organic molecules having a molecular weight greater than that of the unsaturated aldehyde C2n and / or a boiling point greater than that of the unsaturated aldehyde C2n. The crude aldol stream will also comprise unreacted aldehyde Cn along with the alkane(s) Cn-i and alkene(s) Cni.

[0019] The bottom stream of the crude aldol distillation column may also comprise an aqueous phase, for example, at least 80 mol% of the bottom stream may be an aqueous phase. The aqueous phase, for example, when a homogeneous catalyst is used, typically comprises dissolved aldolization reaction catalyst, for example, NaOH. The aqueous phase is separated from the organic phase comprising the unsaturated aldehyde C2n, typically by decantation. Alternatively, there may be no aqueous phase to separate, for example, when a heterogeneous catalyst is used in the aldolization reaction, and the entire bottom stream is an organic phase. The organic phase provides the feed stream for the method for the production of a C2n alcohol described herein.The said method comprises producing an unsaturated aldehyde C2n according to the method of the invention, then a step (vii) of feeding the organic phase of the bottom stream of the crude aldol distillation column to a hydrogenation zone to effect a hydrogenation of the unsaturated aldehyde C2n to provide the alcohol C2n.

[0020] The top vapor stream from the crude aldol distillation column may comprise, for example, at least 15 mol% of combined unreacted Cn-i alkane(s), Cn-i alkene(s) and aldehyde(s) Cn relative to the total moles of the top vapor stream from the aldol distillation column. Petition 870260074513, dated 07 / 27 / 2026, p. 17 / 33 / 24 crude. The top vapor stream from the crude aldol distillation column may comprise at least 50%, by mole, of water relative to the total moles of the top vapor stream from the crude aldol distillation column. The top vapor stream from the crude aldol distillation column may comprise at least 10%, by mole, of unreacted aldehyde Cn relative to the total moles of the top vapor stream from the crude aldol distillation column. The top vapor stream from the crude aldol distillation column may also comprise residual amounts of unsaturated aldehyde C2n, for example, less than 2%, by mole, typically less than 1%, by mole.

[0021] The first condenser zone typically uses a heat exchanger to condense the top vapor stream from the first condenser zone. Preferably, at least a portion (i.e., not all), or substantially all, of the first condensed stream is recovered as a first condensed stream recycle and returned to the aldolization reactor. The first condensed stream typically comprises water, and the first condensed stream is typically passed through a decanter to remove the water before being returned to the aldolization reactor. In the decanter, an aqueous stream is separated from the first condensed stream to provide the first condensed stream recycle. The aqueous stream typically comprises at least 95%, by mole, of water relative to the total moles of the aqueous stream.After passing through the decanter, the first condensed stream recycling stream may comprise, for example, at least 60 mol% of combined unreacted Cn-1 alkane(s), Cn-1 alkene(s) and Cn aldehyde(s), optionally at least 80 mol% of combined unreacted Cn-1 alkane(s), Cn-1 alkene(s) and Cn aldehyde(s) relative to the total moles of the first condensed stream, and optionally less than 5 mol% of water relative to the total moles of the first condensed stream. The first condensed stream may also comprise any remaining residual amounts of unsaturated C2n aldehyde. Petition 870260074513, dated 07 / 27 / 2026, p. 18 / 33 / 24

[0022] The top vapor stream from the first condenser zone may typically comprise, for example, at least 50% by mole of combined unreacted alkane(s) Cn-1, alkene(s) Cn-1 and aldehyde Cn relative to the total moles of the top vapor stream from the first condenser zone. The top vapor stream from the first condenser zone may comprise, for example, at least 10% by mole of aldehyde Cn relative to the total moles of the top vapor stream from the first condenser zone. The top vapor stream from the first condenser zone may also comprise wastewater.

[0023] In the second condenser zone, the condensate Cn / Cn-1 can be produced in a single condensation stage or multiple condensation stages. In each condensation stage, or in the condensation stage, the overhead vapor stream from the first condenser zone can be condensed using a heat exchanger. Alternatively or additionally, in each condensation stage, or in the condensation stage, the overhead vapor stream from the first condenser zone can be condensed by scrubbing with a process stream that is cooler than the overhead vapor stream from the first condenser zone. Such a process stream can be actively cooled, if necessary, so that it is cooler than the overhead vapor stream from the first condenser zone. A suitable process stream is at least a portion of the first condensate recycle stream.In this case, the remaining portion of the first condensate recycle stream can still be returned to the aldolization reactor. Another suitable process stream is a portion of the crude aldehyde stream. In this case, the remaining portion of the crude aldehyde stream is also fed to the crude aldehyde distillation zone. Yet another suitable process stream is a portion of the bottom stream from the crude aldehyde distillation column. In this case, the remaining portion of the bottom stream from the crude aldehyde distillation column is also fed to the aldolization reactor. Such washings improve... Petition 870260074513, dated 07 / 27 / 2026, p. 19 / 33 / 24 further recovers any remaining aldehyde and increases the efficiency of the raw material.

[0024] A portion, i.e., not all or substantially all of the top vapor stream from the first condenser zone may be condensed. Alternatively, if not all of the stream is condensed, a vapor stream will be produced by the second condenser zone, which may be released by venting. This vapor stream suitably comprises an increased concentration of Cn-1 alkane(s) and Cn-1 alkene(s) compared to the top vapor stream from the first condenser zone. This vapor stream may comprise, for example, at least 90%, by mole, of Cn-1 alkane(s) and Cn-1 alkene(s), optionally at least 95%, by mole, of Cn-1 alkane(s) and Cn-1 alkene(s) relative to the total moles of vapor stream. At least a portion (i.e., not all) or substantially all of the Cn / Cn-1 condensate is recovered and returned upstream of the crude aldehyde distillation column or to the crude aldehyde distillation column.The Cn / Cn-1 condensate may typically comprise, for example, at least 50 mol% of Cn-1 alkane(s), Cn-1 alkene(s), and Cn aldehyde combined relative to the total moles of the Cn / Cn-1 condensate. The Cn / Cn-1 condensate may also comprise, for example, at least 15 mol% of Cn aldehyde relative to the total moles of the Cn / Cn-1 condensate. The Cn / Cn-1 condensate may also comprise wastewater. In this case, a decanter may be used to remove the water. In the decanter, an aqueous stream is separated from the Cn / Cn-1 condensate. Typically, at least 20 mol%, optionally at least 50 mol%, or even more optionally at least 90 mol%, of the Cn / Cn-1 condensate is recovered as a recycling stream. Typically, at least 95%, by mole, of the Cn / Cn-1 condensate is returned upstream of the crude aldehyde distillation column or to the crude aldehyde distillation column.Advantageously, this recycling can be performed without the need for expensive compression, which would otherwise be required. Petition 870260074513, dated 07 / 27 / 2026, p. 20 / 33 / 24 because the crude aldol distillation column typically operates at a lower pressure than the crude aldehyde distillation column, because the recycle is supplied as a liquid.

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

[0026] According to a second aspect of the invention, an apparatus is provided for the production of an unsaturated aldehyde C2n, wherein n is in the range of 3 to 6, the apparatus comprising: a hydroformylation reactor configured to place an olefin stream comprising an alkene in contact with hydrogen and carbon monoxide to effect a hydroformylation reaction on the alkene, to provide the feed stream comprising an aldehyde Cn, alkane(s) Cn-1 and alkene(s) Cn-1; a crude aldehyde distillation column configured to receive the crude aldehyde stream and provide a top vapor stream and a bottom vapor stream; an aldolization reactor configured to receive the bottom stream from the crude aldehyde distillation column and to provide a crude aldol stream, with the crude aldol stream comprising an unsaturated aldehyde C2n aldol product, unreacted aldehyde Cn, alkane(s) Cn-1, alkene(s) Cn-1, water and weighed; a crude aldol distillation column configured to receive the crude aldol stream and provide a top vapor stream and a bottom vapor stream; Petition 870260074513, dated 07 / 27 / 2026, p. 21 / 33 / 24 a first condenser zone configured to cool the first top vapor stream to provide a first condensate stream and a top vapor stream; a second condenser zone in fluid communication with the first condenser zone, the second condenser zone being configured to cool the first overhead vapor stream to provide a condensate and, optionally, a vapor stream; The second condenser zone is in fluid communication with or upstream of the crude aldehyde distillation column to return at least a portion of the condensate to or upstream of the crude aldehyde distillation column; whereby the first condenser zone is optionally in fluid communication with the aldolization reactor to return at least a portion of the first condensed stream to the aldolization reactor. BRIEF DESCRIPTION OF THE FIGURES

[0027] Figure 1 illustrates a schematic of a conventional process for the industrial production of aldehydes.

[0028] Figure 2 illustrates a schematic process for the industrial production of aldehydes according to the invention.

[0029] Figure 3 illustrates a schematic process for the industrial production of aldehydes according to the invention.

[0030] Figure 4 illustrates a schematic process for the industrial production of aldehydes according to the invention. DETAILED DESCRIPTION

[0031] The present invention will now be described in detail with reference to the following non-limiting Examples and accompanying figures. Although the present invention is generically described with reference to the production of 2-propyl hept-2-enal, those skilled in the art Petition 870260074513, dated 07 / 27 / 2026, p. 22 / 33 / 24 will acknowledge that the present invention can be applied to the production of any other unsaturated aldehyde C2n.

[0032] 2-alkylalkanols, as described herein, are preferably formed by hydrogenation of an α,β-unsaturated aldehyde, wherein the α,β-unsaturated aldehyde is 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-propyl hept-2-enal.

[0033] Scheme 1 below shows a general process for the production of 2-propyl hept-2-enal and 2-propyl heptanol. Scheme 1: A general process for the production of 2-propyl heptanol from butene.

[0034] The process for the production of 2-propyl hept-2-enal and 2-propyl heptanol will now be described with reference to Scheme 1 above and Figure 1.

[0035] With reference to Figure 1, an olefin stream 1 comprising the Cn-1 alkene, for example but-1-ene, as well as the Cn-1 alkane(s), for example butane isomers, and Cn-1 alkene(s), for example but-1-ene, Petition 870260074513, dated 07 / 27 / 2026, page 23 / 33 / 24 cis-but-2-ene and trans-but-2-ene is fed to a hydroformylation reactor 5. The olefin stream 1 can be fed as a crude cracked product stream from the industrial cracking of hydrocarbons. Those skilled in the art will be familiar with industrial cracking processes. The crude cracked product stream can be subjected to one or more enrichment steps, for example, by passing the crude cracked product stream through one or more distillation columns to increase the concentration of alkene Cn-1 in the olefin stream 1 that is fed to the hydroformylation reactor 5.

[0036] In the hydroformylation reactor 5, the alkene Cn-1 is brought into contact with carbon monoxide and hydrogen, supplied via the synthesis gas stream 3, in the presence of a liquid catalyst solution to provide an aldehyde Cn and, more particularly, pentanal. This hydroformylation process is also known as the oxo process. Typical flow diagrams are described, for example, in US documents 4,148,830 or US 5,087,763, which are incorporated herein by reference. The liquid hydroformylation catalyst system typically comprises a solvent, rhodium, a ligand and other components, but may be any catalyst system suitable for hydroformylation. Typical organophosphine and organophosphite binders are described, for example, in documents WO2008 / 115740, WO2011 / 087690, WO2010 / 117391 and WO2016 / 089602, which are incorporated herein by reference.

[0037] Hydroformylation provides a crude aldehyde stream 7 comprising a mixture of Cn-1 alkane(s), Cn-1 alkene(s) and the Cn aldehyde hydroformylation product, for example pentanal and 2-methylbutanal and 3-methylbutanal isomers in the case of pentanal.

[0038] The crude aldehyde stream 7 is passed to a crude aldehyde distillation zone 9 to increase the aldehyde concentration Cn in the feed stream of the aldolization reactor 13 which is supplied to Petition 870260074513, dated 07 / 27 / 2026, p. 24 / 33 / 24 Aldolization reactor 15. The distillation zone 9 may be a single distillation column or a configuration of multiple distillation columns, provided that a bottom stream 13 comprising aldehyde Cn, alkane(s) Cn-1 and alkene(s) Cn-1 with an increased concentration of aldehyde Cn relative to the crude aldehyde stream is produced together with a top vapor stream 11 comprising an increased concentration of alkane(s) Cn-1 and alkene(s) Cn-1 relative to the crude aldehyde stream. Stream 11 may be exported as a liquid instead of a low-pressure gas, thereby increasing the value of the recovered alkane(s) Cn-1 and alkene(s) Cn-1 stream. Furthermore, part of the stream can be recycled for hydroformylation to convert additional aldehyde Cn.

[0039] Any suitable medium may be used in the distillation zone, and one skilled in the art may determine, for example, which internal column components to use and the appropriate conditions for the desired separation. An additional enrichment step may be included between the crude aldehyde distillation column 9 and the aldolization reactor 15, but it is not essential. For example, a distillation column to increase the amount of linear aldehyde.

[0040] Stream 13 is fed to an aldolization reactor 15. The aldolization reaction is carried out in the aldolization reactor 15 under condensation and dehydration conditions to effect an aldolization reaction of the aldehyde Cn, for example, pentanal, to provide a crude aldol stream comprising an unsaturated aldehyde aldol product C2n, for example, 2-propyl hept-2-enal, together with unreacted aldehyde Cn, Cn-1 alkane(s), Cn-1 alkene(s), water and heavys. Heavys include trace amounts of the aldolization reaction catalyst, for example, sodium hydroxide and salts such as sodium valerate.

[0041] These aldolization steps are known in the art and described, for example, in US documents 5,434,313 and 6,340,778, which are here. Petition 870260074513, dated 07 / 27 / 2026, page 25 / 33 / 24 incorporated by reference. Suitable reagents for carrying out the aldolization reaction in aldolization reactor 15 include a suitable base or acid. The aldolization reaction is preferably carried out in the liquid phase, i.e., the feed stream and reagents are in the liquid phase. Those skilled in the art will know of such suitable acids and bases for the liquid phase reaction, but they may 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, a heterogeneous catalyst may be used, and those skilled in the art will know of such appropriate 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 are able to determine the appropriate conditions for operating the aldolization reaction in order to effect the desired conversion of aldehyde Cn in a single pass.

[0042] The aldolization reaction provides a crude aldol stream 17 comprising unsaturated aldehyde C2n, for example 2-propyl hept-2-enal, unreacted aldehyde Cn, alkane(s) Cn-1, alkene(s) Cn-1, water and heavy. 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.

[0043] The crude aldol stream 17 undergoes an enrichment step by passing the crude aldol stream 17 to a crude aldol distillation column 19 to increase the concentration of unsaturated aldehyde C2n in the bottom stream 21, which may be decanted to remove water before the organic phase is fed to a hydrogenation reactor (not shown) to produce a C2n alcohol, for example 2-propyl heptanol. Petition 870260074513, dated 07 / 27 / 2026, page 26 / 33 / 24

[0044] More particularly, the aldol distillation step comprises passing the crude aldol stream 17 to a crude aldol distillation column 19 operated under distillation conditions to form a bottom stream 21 having an increased concentration of unsaturated aldehyde C2n, water and heavies compared with the crude aldol stream 17 and a top vapor stream 23 comprising unreacted aldehyde Cn, alkane(s) Cn-1, alkene(s) Cn-1 and a reduced concentration of unsaturated aldehyde C2n, water and heavies compared with the crude aldol stream 9. Any suitable medium may be used for the distillation, and one skilled in the art may determine, for example, which internal column components to use and the conditions suitable for the desired separation. Distillations are described, for example, in US patent 5,434,313, which is incorporated herein by reference.

[0045] Figure 1 illustrates a crude aldol distillation column 19 comprised in a conventional industrial process for the production of 2-propyl hept-2-enal. The top vapor stream 23 is passed to the condenser zone 25, which is configured to provide a condensed stream 29 comprising an increased concentration of aldehyde Cn and water compared to the top vapor stream 23 and a vapor stream 27 containing predominantly alkane(s) Cn-1 and alkene(s) Cn-1. The condensed stream 29 also contains alkane(s) CN-1 and alkene(s) CN-1, as well as any unsaturated aldehyde C2n that was present in the first top vapor stream. The condenser zone 25 comprises a heat exchanger for cooling the overhead vapor stream 23 to a temperature of 70 °C to 90 °C, preferably to about 80 °C, particularly in the case of the production of 2-propyl hept-2-enal from pentanal.This stream 29 is passed through a decanter 31 which separates an aqueous stream 33 and a recycling stream 35 which recycles the organics back to the aldolization reactor 15. To relieve the pressure buildup inside the crude aldol distillation column 19, a. Petition 870260074513, dated 07 / 27 / 2026, p. 27 / 33 / 24 Vapor stream 27 is simply purged during the distillation process. Vapor stream 27 typically contains some aldehyde Cn, as well as alkane(s) Cn-1 and alkene(s) Cn-1, thus, aldehyde Cn is lost from the process in the purge.

[0046] Figure 2 is a schematic diagram of a method according to the invention in which there are the first 25 and second 37 condenser zones above the crude aldol distillation column.

[0047] The first condenser zone 25 comprises a first heat exchanger. The top vapor stream 23 from the crude aldol distillation column is cooled in the heat exchanger, for example, by means of a cold water stream. At least a portion of the first condensed stream 29 is decanted and recycled to the aldolization reactor 15 according to the method in Figure 1. Typically, the first top vapor stream 23 is cooled in the heat exchanger 25 to a temperature of 70 °C to 90 °C, preferably to about 80 °C, particularly in the case of the production of 2-propyl hept-2-enal from pentanal.

[0048] Instead of venting, as per the conventional process in Figure 1, the top vapor stream 27 from the first condenser zone is sent to a second condenser zone 37. The second condenser zone is configured to provide a Cn / Cn-1 condensate stream 41 comprising an increased concentration of the aldehyde Cn, for example, pentanal, compared to the second top vapor stream 27. Optionally, a vapor stream 39 is also provided, comprising an increased concentration of Cn-1 alkane(s) and Cn1 alkene(s), for example, butane isomers together with but-1-ene, cis-but-2-ene and trans-but-2-ene, compared to the second top vapor stream 27.

[0049] The second capacitor zone comprises a heat exchanger to supply the Cn / Cn-1 41 condensate stream. The second stream Petition 870260074513, dated 07 / 27 / 2026, p. 28 / 33 / 24 of top vapors 27 is cooled in the second heat exchanger, typically by means of a cold water stream. Preferably, the second top vapor stream 41 is cooled in the second heat exchanger 37 from about 2 °C to 50 °C, optionally from 35 °C to 45 °C, even more optionally from 35 °C to 40 °C, for example, to about 38 °C, particularly in the case of the production of 2-propyl hept-2-enal from pentanal. The Cn / Cn-1 condensate 41 is passed through a decanter 43 which separates an aqueous stream 45 and a recycling stream 47 which recycles the organics back to the crude aldehyde distillation column 9. This distillation column is more effective at separating Cn aldehyde from Cn-1 alkane(s) and Cn-1 alkene(s), and facilitates the efficient recycling of unreacted Cn aldehyde back to the aldolization step, rather than wasting it on vent release.The recovery of Cn-1 alkanes and Cn-1 alkenes from the crude aldehyde distillation zone further enables the stream to be exported as a liquid instead of a low-pressure gas, thus increasing the value of the recovered Cn-1 alkane(s) and Cn-1 alkene(s) stream(s).

[0050] Figure 3 is a schematic diagram of another method according to the invention in which there are the first 25 and second 37 condenser zones above the crude aldol distillation column. In this method, the recycle stream 35, which is cooler than the overhead vapor stream 27, is used to wash the overhead vapor stream 27 and condense the stream to provide the Cn / Cn-1 condensate stream 41 instead of a heat exchanger. The stream 41 is passed through the decanter 43 to provide the recycle stream 47 which recycles organics back to the crude aldehyde distillation column 9. The vapor stream 39 containing alkane(s) Cn-1 and alkene(s) Cn1 is optional.

[0051] Figure 4 is a schematic diagram of another method according to the invention in which there are the first 25 and second 37 condenser zones above the crude aldol distillation column. In this method, a portion of Petition 870260074513, dated 07 / 27 / 2026, p. 29 / 33 / 24 crude aldehyde stream 7 is used to wash the top vapor stream 27 and condense the stream to provide the Cn / Cn-1 condensate stream 41 instead of a heat exchanger. If necessary, this wash stream is cooled in a cooling stage (not shown). Stream 41 is passed through the decanter 43 to provide the recycling stream 47 which recycles organics back to the crude aldehyde distillation column 9. The vapor stream 39 containing Cn-1 alkane(s) and Cn-1 alkene(s) is optional. A portion of the crude aldehyde stream 7 is also fed to the crude aldehyde distillation zone 9.

[0052] The bottom stream 21 from the crude aldol distillation column in Figures 1 to 4, comprising an increased concentration of unsaturated aldehyde C2n, for example 2-propyl hept-2-enal, can then be decanted to remove the aqueous phase before the organic phase is fed to a hydrogenation reactor (not shown). Under hydrogenation conditions in the reactor in the presence of hydrogen and a catalyst, the unsaturated aldehyde C2n is hydrogenated to give an alcohol C2n, for example, 2-propyl heptanol. Suitable hydrogenation processes are known in the art and disclosed, for example, in document WO2018 / 069714, which is incorporated herein by reference. The hydrogenation reactor can be operated under any suitable conditions. A catalyst will generally be used. Any suitable catalyst can be used. Generally, the active component of the catalyst is based on metals from Groups VI to X.Suitable examples include copper, nickel, manganese, zinc, cobalt, palladium, ruthenium, and iron. The catalyst may be supported. Any suitable support may be used. Suitable supports include alumina, silica, or diatomaceous earth. A particularly suitable catalyst may be a supported copper chromite catalyst. The catalyst may also include a promoter to increase selectivity.

[0053] Hydrogenation can be carried out in the liquid or vapor phase. Petition 870260074513, dated 07 / 27 / 2026, page 30 / 33 / 24 Any suitable configuration can be used and the reactor can be operated under any suitable conditions. Although the specific conditions selected depend on the catalyst chosen, hydrogenation can be carried out at a temperature of about 100 °C to about 200 °C and at an atmospheric pressure of about 15 MPa.

[0054] When liquid-phase hydrogenation is to be used, it can be carried out in any suitable manner. In one arrangement, it can be done as a downflow over fixed catalytic beds. A large amount of cooled product can be recycled and mixed with the feed stream in order to remove the heat of reaction. An example of a suitable process is described in document GB1362071, which is incorporated herein by reference. In an alternative arrangement, one or more heat exchangers can be used to remove the heat of reaction.

[0055] The crude alcohol stream comprising C2n alcohol, for example 2-propyl heptanol, can then be purified through one or more purification steps to provide a purified alcohol stream. For example, the crude alcohol stream can be subjected to one or more distillation and polishing steps, for example, as described, for example, in document WO2018 / 069714. Examples

[0056] The following example demonstrates that the method and apparatus according to the present invention enable the significant recovery of unreacted C5 aldehyde that would otherwise be waste. The following example uses a computational model of the system schematically illustrated in Figure 2 using the AVEVA PROII simulator and known properties (e.g., boiling point, density, etc.) of known components (e.g., water, butene, pentanal) in each stream, and vapor-liquid equilibrium data. The data demonstrate that significant quantities of useful small organic molecules can be recovered from the stream. Petition 870260074513, dated 07 / 27 / 2026, page 31 / 33 / 24 of Cn / Cn-i 41 condensate using the methods and apparatus of the present invention.

[0057] The simulation analysis results are provided in the table below. Table 1________________________________________________________________ Figure 1 (Comparative) Figure 2 Top vapor stream 27 Top vapor stream 39 Cn / Cn-1 condensate stream 41 Stream composition (%, mol) H2O 26.4 3.5 1.3 2-methylbutyraldehyde (2MBH) 10.1 1.4 18.3 Pentanal 14.8 1.4 27.2 3-methylbutyraldehyde (3MBH) 0.1 0.0 0.2 But-1-ene 0.0 0.1 0.0 Cis-But-2-ene 12.6 25.1 13.5 Trans-but-2-ene 23.5 49.1 24.2 Pentane 0.6 0.4 1.0 Butane 11.8 19.1 14.4 Stream properties Mass flow rate (Kg / h) 327 86 214 Vapor Phase Vapor Liquid Phase Molecular Weight* 53.9 56.1 69.8 Pressure (MPa) 0.18 0.17 0.17 Temperature (°C) 80 38 38 *average molecular weight of the stream based on the %, in moles, of the components in the relevant stream

[0058] These data show that the apparatus in Figure 3 advantageously enables significant recovery of C5 aldehyde, which can be recycled to the crude aldehyde distillation column and re-enter the aldolization reaction, with concomitant separation and recovery of C4 alkanes and alkenes. As demonstrated by the mass flow rate, most of the composition of the top vapor stream 27 in conventional methods is recovered as recyclable organics in the Cn / Cn-i condensate stream 41 using the methods of the invention. Petition 870260074513, dated 07 / 27 / 2026, pages 32 / 33 / 24

[0059] The apparatus in Figure 2 is calculated to result in approximately a 1% increase in the yield of 2-propyl heptanol after hydrogenation of the 2-propyl hept-2-enal produced, compared to using the apparatus in Figure 1.

[0060] The table below shows the effect of the temperature of the second heat exchanger in methods and apparatus of the present invention on the mass flow rate of the condensate stream of Cn / Cn-1 41. Table 2 Condensation temperature (°C) 36 38 40 42 Mass flow rate (Kg / h); Condensate stream of Cn / Cn-1 41 227 214 202 192 Petition 870260074513, dated 07 / 27 / 2026, page 33 / 33

Claims

1 / 5 CLAIMS 1. Method for the production of an unsaturated aldehyde C2n, wherein n is in the range of, inclusive, 3 to 6, the method being characterized in that it comprises: (i) feeding an olefin stream comprising an alkene Cn-1 to a hydroformylation reactor and contacting the olefin stream with a hydroformylation gas stream comprising hydrogen and carbon monoxide to effect a hydroformylation reaction to provide a crude aldehyde stream comprising an aldehyde Cn, alkane(s) Cn-1 and alkene(s) Cn-1;(ii) feeding the crude aldehyde stream to a crude aldehyde distillation zone operated under distillation conditions to form a bottom stream comprising Cn aldehyde, Cn-1 alkane(s) and Cn-1 alkene(s) and comprising an increased concentration of Cn aldehyde relative to the crude aldehyde stream and a top vapor stream comprising an increased concentration of Cn-1 alkane(s) and Cn-1 alkene(s) relative to the crude aldehyde stream; (iii) feeding the bottom stream from the crude aldehyde distillation column to an aldolization reactor under condensation and dehydration conditions to effect an aldolization reaction of Cn aldehyde to provide a crude aldol stream comprising an unsaturated aldol product C2n aldehyde, unreacted Cn aldehyde, Cn-1 alkane(s), Cn-1 alkene(s), water and weighed;(iv) pass the crude aldol stream to a crude aldol distillation column operated under distillation conditions to form a bottom stream having an increased concentration of unsaturated aldehyde C2n, water and heavy compared to the crude aldol stream and a top vapor stream comprising unreacted aldehyde Cn, alkane(s) Cn-1, alkene(s) Cn-1 and a reduced concentration of unsaturated aldehyde C2n, water and heavy compared to the crude aldol stream;(v) pass the top vapor stream from the crude aldol distillation column to a first condenser zone, the first condenser zone being configured to provide a first condensate stream comprising an increased concentration of unreacted aldehyde Cn and water compared to the top vapor stream from the crude aldol distillation column, and a top vapor stream comprising Cn-1 alkane(s), Cn-1 alkene(s) and a reduced concentration of unreacted aldehyde Cn and water compared to the top vapor stream from the crude aldol distillation column; (vi) pass the top vapor stream from the first condenser zone to a second condenser zone, the second condenser zone being configured to condense at least a portion of the top vapor stream from the first condenser zone to provide the Cn / Cn-1 condensate;and provided that at least a portion of the Cn / Cn-1 condensate is recovered and returned upstream of the crude aldehyde distillation column or to the crude aldehyde distillation column.

2. Method according to claim 1, characterized in that at least a portion of the first condensate stream is recovered as a first condensate recycle stream and returned to the aldolization reactor.

3. A method according to claim 1 or claim 2, characterized in that the second condenser zone is configured to condense substantially all of the top vapor stream from the first condenser zone.

4. Method according to any of the preceding claims, characterized in that at least a portion of the top vapor stream of the first condenser zone is condensed by washing Petition 870250072874, dated 08 / 18 / 2025, page 37 / 44 3 / 5 with a process stream.

5. A method according to any of the preceding claims, characterized in that at least a portion of the top vapor stream of the first condenser zone is condensed using a heat exchanger.

6. A method according to any of the preceding claims, characterized in that the temperature of the first condenser zone is higher than the condensation temperature of the second condenser zone.

7. A method according to any of the preceding claims, characterized in that n is 3, 4, or 5.

8. Method according to claim 7, characterized in that the unsaturated aldehyde C2n is a 2-alkylalkenal.

9. Method according to claim 8, characterized in that the unsaturated aldehyde C2n is 2-propyl hept-2-enal.

10. A method according to any of the preceding claims, characterized in that the aldehyde Cn is pentanal.

11. Method according to any of the preceding claims, characterized in that the crude aldehyde distillation zone comprises a single crude aldehyde distillation column operated under distillation conditions to form a bottom stream comprising aldehyde Cn, alkane(s) Cn-1 and alkene(s) Cn-1, and comprising an increased concentration of aldehyde Cn relative to the crude aldehyde stream and a top vapor stream comprising an increased concentration of alkane(s) Cn-1 and alkene(s) Cn-1 relative to the crude aldehyde stream.

12. Method for the production of an alcohol C2n, the method being characterized in that it comprises the production of an unsaturated aldehyde C2n as defined in the method of any of the preceding claims Petition 870250072874, dated 18 / 08 / 2025, page 38 / 44 4 / 5, then a step (vii) of feeding the organic phase from the bottom stream of the crude aldol distillation column to a hydrogenation zone to effect a hydrogenation of the unsaturated aldehyde C2n to provide the alcohol C2n.

13. Apparatus for the production of an unsaturated aldehyde C2n, wherein n is in the range of 3 to 6, the apparatus being characterized in that it comprises: a hydroformylation reactor configured to bring an olefin stream comprising an alkene into contact with hydrogen and carbon monoxide to effect a hydroformylation reaction on the alkene, to provide the feed stream comprising an aldehyde Cn, alkane(s) Cn-1 and alkene(s) Cn-1; a crude aldehyde distillation column configured to receive the crude aldehyde stream and provide a top vapor stream and a bottom vapor stream; an aldolization reactor configured to receive the bottom stream from the crude aldehyde distillation column and to supply a crude aldol stream, wherein the crude aldol stream comprises an unsaturated aldehyde C2n aldol product, unreacted aldehyde Cn, alkane(s) Cn1, alkene(s) Cn-1, water and weighed;a crude aldol distillation column configured to receive the crude aldol stream and provide a top vapor stream and a bottom vapor stream; a first condenser zone configured to cool the first top vapor stream to provide a first condensate stream and a top vapor stream; a second condenser zone in fluid communication with the first condenser zone, wherein the second condenser zone is configured to cool the first top vapor stream to provide a condensate and, optionally, a vapor stream; wherein the second condenser zone is in fluid communication with the crude aldehyde distillation column or upstream of the crude aldehyde distillation column to return at least a portion of the condensate to the crude aldehyde distillation column or upstream of the crude aldehyde distillation column;whereby the first condenser zone is optionally in fluid communication with the aldolization reactor to return at least a portion of the first condensed stream to the aldolization reactor. Petition 870250072874, dated 08 / 18 / 2025, pp. 40 / 44;

Images