Regeneration of triphenylphosphine oxide

Abstract

The present invention relates to an improved process for preparing triphenylphosphine (TPP) by reacting triphenylphosphine oxide (TPPO) with a catalyst in the presence of an inert solvent and employing the addition of certain alcohols.

Description

Detailed Description of the Invention

[0001] The present invention relates to an improved process for preparing triphenylphosphine (TPP) by reacting triphenylphosphine oxide (TPPO) with a catalyst in the presence of an inert solvent and employing the addition of certain alcohols.

[0002] Formula (I) [ka] The compound TPP is used on an industrial scale in Wittig ylide synthesis to prepare olefinic compounds such as vitamin A or carotenoids. TPP is used in stoichiometric amounts and has the formula (II) [ka] is oxidized to the compound TPPO.

[0003] Thus, although a lot of TPPO is produced during these reactions, unfortunately, few uses of TPPO have been disclosed. Because TPPO is a very stable substance that can be quite difficult to dispose of, there have been numerous attempts to convert it to TPP.

[0004] One common way to deal with the TPPO problem is to burn it so that it can be disposed of in a safe manner, and therefore the phosphorus can be reused again instead of sourcing it again.

[0005] Another method is recycling TPPO into TPP, which can then be reused again.

[0006] Such recycling processes are known from the prior art (i.e. from EP 638580 B1, Heteroatom Chemistry 26(3), 2015, p. 199-205).

[0007] Most of these recycling processes involve the use of Ti compounds as catalysts, in combination with the formula (III) (CH3)3Si-(CH3(H)Si-O) n -Si(CH3)3(III) (In the formula, n is usually a value of 10 to 100,000 (preferably, n is a value of 100 to 20,000, more preferably, n is a value of 1,000 to 12,000, and most preferably, n is a value of 1,000 to 10,000). This is carried out in the presence of polymethylhydrosiloxane (PMHS), a compound of the formula:

[0008] Berthod et al., in SYNLETT, vol. 2007, no. 10, pp. 1545-1548, describe a specific method using hydroxysilanes such as TMDS and PMHS in the presence of Ti- or Zr-compounds as catalysts for reducing TPPO to regenerated TPP. Berthod et al. point out that PMHS is disadvantageous for workup and recovery due to gel formation, while TMDS has higher reactivity. Berthod et al. further report that no significant reduction of TPPO to TPP was observed using zirconium-based catalysts.

[0009] Nevertheless, the use of PMHS as a reducing agent has one major drawback, namely the need for a work-up procedure.

[0010] This work-up procedure is usually carried out at a very high pH to hydrolyze unreacted PMHS, and therefore consumes large amounts of base such as KOH or NaOH (typically more than 10 equivalents) and also generates large amounts of wastewater.

[0011] Due to the importance of the reactions in which TPPO is produced (as a waste product) and the problems associated with using TPPO and its disposal, there is a need for improved methods for converting TPPO to TPP, which can then be used again, while minimizing the amount of wastewater produced.

[0012] Surprisingly, it has now been found that, using certain reaction conditions, it is possible to reduce TPPO directly to TPP in excellent yield, and the workup of the reaction mixture is carried out in an improved manner.

[0013] The present invention therefore relates to a process (P) for producing triphenylphosphine (compound of formula (I)): [ka] First (Step 1), triphenylphosphine oxide (compound of formula (II)) [ka] with formula (III) (CH3)3Si-O-(CH3(H)Si-O) n -Si(CH3)3(III) (In the formula, n is a value of 10 to 100,000 (preferably, n is a value of 100 to 20,000, more preferably, n is a value of 1,000 to 12,000, and most preferably, n is a value of 1,000 to 10,000). and a compound of formula (IV) [ka] (Wherein M is titanium (Ti) or zirconium (Zr), or a mixture of compound (IV) in which M is Ti and compound (IV) in which M is Zr; R, R1, R2 and R3 are each independently OR4; wherein R4 is a linear or branched C1-C6 alkyl group. In the presence of at least one catalyst reacting in at least one aromatic solvent and / or at least one alkane at elevated temperature; In the second step (step 2), Formula (V) R5-OH(V) wherein R5 is a linear or branched C1-C6 alkyl moiety. is added to the reaction mixture.

[0014] At the end of the process, the solvent (or mixture of solvents) is removed (eg, by distillation) to yield a compound of formula (I).

[0015] The compounds of formula (I) can be further purified by using commonly known processes.

[0016] Typically, the resulting compound of formula (I) is washed with the same alcohol of formula (V) (or a mixture thereof) as used in step 2.

[0017] The solvent used in the process according to the invention is at least one aromatic solvent and / or at least one alkane.

[0018] Suitable and preferred aromatic solvents are benzene, benzene substituted with one or more C1-C4-alkyl groups, or benzene substituted with one or more O—C1-C4-alkyl groups, or mixtures thereof.

[0019] More preferred aromatic solvents are benzene, toluene, mesitylene, xylene and anisole, as well as diethylbenzene in isomerically pure form or as a mixture of o-, m- and p-isomers, and solvent naphtha, also called petroleum, such as, for example, Solvesso 100 by Exxon Mobil, or mixtures thereof.

[0020] The present invention therefore also relates to a process (P1), which is a process (P), in which the at least one aromatic solvent is selected from the group consisting of benzene, benzene substituted with one or more C1-C4-alkyl groups, and benzene substituted with one or more O-C1-C4-alkyl groups.

[0021] Therefore, the present invention also relates to a process (P1'), which is process (P), wherein the at least one aromatic solvent is selected from the group consisting of benzene, toluene, mesitylene, xylene, diethylbenzene (pure or a mixture of isomers), and anisole, or mixtures thereof.

[0022] Suitable alkanes are C4-C 18 -alkanes, which can be linear, branched and cyclic.

[0023] Suitable alkanes are pentane, hexane, heptane, octane, decane, undecane, dodecane, or any mixture of alkanes (ie, Isopar M, etc.).

[0024] Therefore, the present invention also relates to a process (P2), which is a process (P), in which at least one alkane is a C4-C6 alkane, which may be linear, branched or cyclic. 18 - an alkane.

[0025] Thus, the present invention also relates to a process (P2'), which is process (P), wherein the at least one alkane is selected from the group consisting of pentane, hexane, heptane, octane, decane, undecane, dodecane, and any mixture of alkanes.

[0026] At the start of the process according to the invention, TPPO is suspended in at least one aromatic solvent and / or at least one alkane and PMHS (compound of formula (III)) is added.

[0027] PMHS is usually and preferably added in an amount of 1.0 to 4 molar equivalents (calculated relative to the active hydrogen content of the PMHS taking into account the amount of TPPO).

[0028] Therefore, the present invention also relates to a process (P3), which is a process (P), (P1), (P1'), (P2) or (P2'), in which the compound of formula (III) is added in an amount of 1.0 molar equivalent to 4 molar equivalents (calculated relative to the active hydrogen content of the PMHS, taking into account the amount of TPPO).

[0029] The process according to the invention is carried out in the presence of at least one catalyst (a compound of formula (IV)), in which M represents a metal of group 4 of the periodic table, preferably titanium (Ti) or zirconium (Zr).

[0030] In another embodiment of the present invention, the process is carried out in the presence of a catalyst using a mixture of a compound of formula (IV) wherein M is Ti (compound (IV)-Ti) and a compound of formula (IV) wherein M is Zr (compound (IV)-Zr).

[0031] In such embodiments, a mixture of Compound (IV)-Ti and Compound (IV)-Zr may be used in a ratio of (IV)-Ti:(IV)-Zr of 1:99 to 99:1, preferably a ratio of 20:80 to 80:20, or most preferably a ratio of 40:60 to 60:40. [ka]

[0032] In the compound of formula (IV), Preferably, R, R1, R2 and R3 are each independently OR4; wherein R4 is a straight-chain or branched C1-C6 alkyl group, more preferably R4 is a straight-chain or branched C1-C6-alkyl, most preferably a straight-chain or branched C2-C5-alkyl.

[0033] Even more preferably, R4 is ethyl, iso-propyl, n-propyl, iso-butyl or n-butyl.

[0034] Thus, the present invention also relates to process (P4), which is process (P), (P1), (P1'), (P2), (P2') or (P3), in which compound R4 of formula (IV) is a linear or branched C2-C6-alkyl.

[0035] Thus, the present invention also relates to process (P4'), which is process (P), (P1), (P1'), (P2), (P2') or (P3), in which compound R4 of formula (IV) is a linear or branched C2-C5-alkyl.

[0036] Thus, the present invention also relates to Process (P4″), which is Process (P), (P1), (P1′), (P2), (P2′) or (P3), wherein the compound R4 of formula (IV) is selected from the group consisting of ethyl, iso-propyl, n-propyl, iso-butyl and n-butyl.

[0037] In the compound of formula (IV), R, R1, R2, R3 and R4 may be the same substituent, but they may also be different from each other.

[0038] Preferably, R, R1, R2, R3 and R4 have the same meaning.

[0039] In the process according to the invention, the catalyst which is a compound of formula (IV) is typically and preferably used in an amount of 1 to 20 mol %, more preferably in an amount of 1 to 15 mol %, most preferably in an amount of 6 to 14 mol % (relative to the amount of TPPO).

[0040] In a preferred embodiment, the process is carried out in the presence of a catalyst which is a mixture of compounds (IV)-Ti and (IV)-Zr, typically used in an amount of 1-20 mol %, preferably 1-15 mol %, more preferably 1-12 mol %, and most preferably 1-10 mol % each (relative to the amount of TPPO).

[0041] Thereby, the amount of compound (IV), which is a mixture of compound (IV)-Ti and compound (IV)-Zr, is used in a ratio of (IV)-Ti:(IV)-Zr of 3:1 to 1:3, preferably 3:2 to 2:3, most preferably 1:1, with a typical amount of compound (IV)-Ti being 1-10 mol % and a typical amount of compound (IV)-Zr being 1-10 mol %, more preferably a typical amount of compound (IV)-Ti being 1-5 mol % and a typical amount of compound (IV)-Zr being 1-5 mol %.

[0042] In another embodiment of the present invention, the above process is carried out in the presence of a catalyst, in which case when the catalyst is a mixture of compound (IV)-Ti and compound (IV)-Zr, all four substituents R4 are the same within the same compound (IV), and therefore compound (IV)-Ti may have four identical substituents that are the same as or different from the four identical substituents of compound (IV)-Zr. Preferably, the process described herein above is carried out in the presence of a catalyst, in which case when a mixture of compounds (IV) is used, R4 is different in compound (IV)-Ti than in compound (IV)-Zr, for example, in such a mixture, compound (IV)-Ti may contain iPr as R4, while compound (IV)-Zr may contain nBu as R4 substituent.

[0043] According to the present invention, in step 1, the compound of formula (IV) is typically and preferably used as a solution of compound (IV) in a suitable solvent. The suitable solvent is selected from the group consisting of ethyl, isopropyl, n-propyl, isobutyl, and n-butyl alcohol. Preferably, the solvent corresponds to the substituent R4 used in compound (IV). Preferably, compound (IV) is used in a concentration of up to 100%, preferably 20-99% w / w, of the solution of compound (IV) in the solvent.

[0044] Thus, the present invention also relates to process (P5), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4') or (P4''), in which the compound of formula (IV) is used in an amount of 1 to 20 mol %, more preferably 1 to 15 mol %, most preferably 6 to 14 mol % (based on the amount of TPPO).

[0045] In the process according to the invention, step 1 is carried out at an elevated temperature. Preferably, step 1 is carried out at a temperature between 100°C and 200°C, more preferably between 150°C and 180°C.

[0046] Thus, the present invention also relates to process (P6), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4') or (P4'') or (P5), in which step 1 is carried out at a temperature between 100°C and 200°C.

[0047] Thus, the present invention also relates to process (P6'), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4'') or (P5), in which step 1 is carried out at a temperature of 150°C to 180°C.

[0048] If the solvent (or mixture of solvents) is a low boiling point solvent, step 1 is preferably carried out in an autoclave.

[0049] The reaction time for step 1 of the process according to the present invention is usually several hours. Typically and preferably, the reaction time for step 1 of the process according to the present invention is 3 to 10 hours.

[0050] Therefore, the present invention also relates to Process (P7), which is Process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6) or (P6'), in which the reaction time of Step 1 is 3 to 10 hours.

[0051] In a preferred embodiment, the solvent or mixture of solvents is removed (completely or partially) from the reaction mixture after step 1. This step (step 1a) can be carried out by using commonly known methods (such as distillation).

[0052] Thus, the present invention also relates to process (P8), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6') or (P7), in which after step 1 the solvent or mixture of solvents is removed (fully or partially) from the reaction mixture.

[0053] After step 1 (or after step 1a), the reaction mixture is cooled to a temperature below 100°C, typically to a temperature of 40°C to 90°C.

[0054] Thus, the present invention also relates to process (P9), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7) or (P8), in which after step 1 (or after step 1a) the reaction mixture is cooled to a temperature below 100°C.

[0055] Thus, the present invention also relates to process (P9'), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7) or (P8), in which after step 1 (or after step 1a) the reaction mixture is cooled to a temperature of 40°C to 90°C.

[0056] In step 2 of the process according to the invention (which is carried out after step 1 or 1a), a compound of formula (V) R5-OH wherein R5 is a linear or branched C1-C6 alkyl moiety, is added to the reaction mixture.

[0057] Preferably, R5 is a straight or branched C1-C4 alkyl moiety.

[0058] More preferably, the at least one alcohol of formula (V) is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol. Most preferably, the at least one alcohol of formula (V) is isopropanol.

[0059] Thus, the present invention also relates to process (P10), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9) or (P9'), in which the alcohol of formula (V)R5 is a linear or branched C1-C4-alkyl moiety.

[0060] Thus, the present invention also relates to process (P10'), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9) or (P9'), wherein the alcohol is selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol, preferably isopropanol.

[0061] The alcohol of formula (V) is typically and preferably added to the reaction mixture in molar excess (relative to TPPO). Typically, at least one alcohol is added in at least an amount of 1 to 30 molar equivalents (relative to TPPO).

[0062] Thus, the present invention also relates to Process (P11), which is Process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9), (P9'), (P10) or (P10'), wherein at least one alcohol of formula (V) is added to the reaction mixture in molar excess (relative to TPPO).

[0063] Thus, the present invention also relates to Process (P11'), which is Process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9), (P9'), (P10) or (P10'), wherein at least one alcohol of Formula (V) is added to the reaction mixture in at least an amount of 1 to 30 molar equivalents (relative to TPPO).

[0064] Preferably, in step 2, the reaction mixture is heated to a temperature of 40 to 90°C.

[0065] Thus, the present invention also relates to Process (P12), which is Process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9), (P9'), (P10), (P10'), (P11) or (P11'), wherein in Step 2, the reaction temperature is 40 to 90°C.

[0066] Finally, the reaction mixture is cooled to a low temperature, typically between -10°C and 10°C.

[0067] Thus, the present invention also relates to Process (P13), which is Process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9), (P9'), (P10), (P10'), (P11), (P11') or (P12), wherein at the end of the reaction in Step 2, the reaction temperature is cooled to -10°C to 10°C.

[0068] At this point the TPP precipitates and can be filtered off.

[0069] Usually, the product obtained (TPP) is washed with the same alcohol (or mixture of alcohols) of formula (V) already added during step 2.

[0070] As a further feature, the mother liquor obtained at the end of step 2 and after the (optional) washing can be further processed.

[0071] The filter cake was washed with the same alcohol solvent used in the previous step.

[0072] Additionally, the present inventors have discovered that treating the mother liquor with ammonium hydroxide (which is an aqueous solution of NH3) has several surprising beneficial effects.

[0073] Upon addition of ammonium hydroxide, the Si-containing compounds form a solid precipitate which also incorporates titanium derived from the catalyst and can be removed from the solution.

[0074] This unexpected discovery allowed the removal of almost all of the silicium and titanium in the aqueous alcohol solution.

[0075] Thus, the present invention also relates to process (P14), which is process (P), (P1), (P1'), (P2), (P2'), (P3), (P4), (P4'), (P4''), (P5), (P6), (P6'), (P7), (P8), (P9), (P9'), (P10), (P10'), (P11), (P11'), (P12) or (P13), in which in the third step (step 3) the mother liquor (obtained after step 2) is treated with ammonium hydroxide.

[0076] Typically and preferably, the mother liquor is treated with ammonium hydroxide having a concentration of 1 to 30 weight percent (wt%) of NH3 in H2O, based on the total weight of the ammonium hydroxide.

[0077] Accordingly, the present invention also relates to process (P15), which is process (P14), wherein the ammonium hydroxide has a concentration of 1 to 30 weight percent (wt%) of NH in HO, based on the total weight of the ammonium hydroxide.

[0078] The treatment of the mother liquor is carried out at a temperature of 40°C to 120°C, preferably 60°C to 100°C.

[0079] Therefore, the present invention also relates to a process (P16), which is a process (P14) or (P15), in which step 3 is carried out at a temperature between 40°C and 120°C.

[0080] Therefore, the present invention also relates to a process (P16'), which is a process (P14) or (P15), in which step 3 is carried out at a temperature between 60°C and 100°C.

[0081] Optionally, the treatment of the mother liquor can be carried out in the presence of at least one surfactant.

[0082] Suitable surfactants are cetyltrimethylammonium bromide, myristyltrimethylammonium bromide, dodecyltrimethylammonium bromide, or hexadecyltrimethylammonium bromide.

[0083] Thus, the present invention also relates to process (P17), which is process (P14), (P15), (P16) or (P16'), in which step 3 is carried out in the presence of at least one surfactant.

[0084] Accordingly, the present invention also relates to Process (P17′), which is Process (P14), (P15), (P16), or (P16′), wherein step 3 is carried out in the presence of at least one surfactant selected from the group consisting of cetyltrimethylammonium bromide, myristyltrimethylammonium bromide, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, cetyltrimethylammonium chloride, myristyltrimethylammonium chloride, dodecyltrimethylammonium chloride, and hexa-decyl-trimethylammonium chloride.

[0085] Optionally, tetraethyl orthosilicate can also be used to treat the mother liquor.

[0086] Thus, the present invention also relates to process (P18), which is process (P14), (P15), (P16), (P16'), (P17) or (P17'), wherein step 3 is carried out in the presence of tetraethyl orthosilicate.

[0087] Furthermore, the present invention relates to the use of triphenylphosphine (TPP) produced by the above-mentioned process for the production of a carotenoid selected from the group of carotenoids including α-, β-, γ-, or δ-carotene, apocarotenal, β-apo-8'-carotenal, β-apo-12'-carotenal, lycopene, and bixin, or a carotenoid selected from the group of carotenoids including lutein, astaxanthin, canthaxanthin, citranaxanthin, cryptoxanthin, flavoxanthin, violaxanthin, or zeaxanthin.

[0088] The present invention also provides i) producing TPP from waste containing TPPO according to the process described above; ii) subjecting each carotenoid building block compound to a coupling reaction with TPP as a coupling reagent, which is produced according to the above step i); iii) recovering each carotenoid; The present invention relates to a method for producing a carotenoid comprising the steps of:

[0089] The coupling reaction defined above can be any reaction for the formation of a C=C bond, preferably a Wittig reaction, as described in DE 954247. The building block compounds according to the invention can have at least two structures, independently of one another, having C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13 and at least one functional group suitable for reacting accordingly in such a coupling reaction.

[0090] The present invention also relates to a carotenoid obtained by the above method, in which the carotenoid is selected from the group of carotenes, including α-, β-, γ- or δ-carotene, apocarotenal, β-apo-8'-carotenal, β-apo-12'-carotenal, lycopene, bixin, or from the group of xanthophylls, including lutein, astaxanthin, canthaxanthin, citranaxanthin, cryptoxanthin, flavoxanthin, violaxanthin, or zeaxanthin.

[0091] The following examples illustrate the present invention.

[0092] [Example] [Example 1:] 70 g of TPPO was charged to an autoclave, and 270 g of toluene was added. 37 g of PMHS was added. 7 g of Ti(OiPr)4 was added. The autoclave was closed, and the reaction mixture was heated to 170 °C for 6 hours. The reaction mixture was then cooled to 55 °C. The toluene was distilled off (more than 90% of the amount initially used). 169 g of iPrOH (isopropanol) was added, and the reaction temperature was maintained at 55 °C until the solid dissolved. The reaction mixture was cooled to 0 °C, allowing the TPP to crystallize. The TPP was filtered off and washed with iPrOH. Finally, the TPP was dried to yield 55 g of material.

[0093] Example 2 70 g of TPPO was charged into an autoclave, and 270 g of toluene was added. 32 g of PMHS and 5.5 g of Ti(OiPr)4 were added. The autoclave was closed, and the reaction mixture was heated to 170 °C for 6 hours. The reaction mixture was then cooled to 60 °C. Toluene was distilled off (more than 90% of the amount initially used). 169 g of iPrOH was added, and the reaction temperature was maintained at 60 °C until the solid dissolved. The reaction mixture was cooled to 2 °C, allowing the TPP to crystallize. The TPP was filtered off and washed with iPrOH. Finally, the TPP was dried to yield 46 g of material.

[0094] Example 3 70 g of TPPO was charged into an autoclave and 270 g of toluene was added. 38 g of PMHS and 8.5 g of Ti(OnBu)4 were added. The autoclave was closed and the reaction mixture was heated to 170°C for 6 hours. The reaction mixture was then cooled to 57°C. The toluene was distilled off (more than 90% of the amount originally used). 168 g of iPrOH was added and the reaction temperature was maintained at 65°C until the solid dissolved. The reaction mixture was cooled. The TPP was filtered off and washed with iPrOH. The TPP was filtered off and washed with iPrOH. Finally, the TPP was dried to give 55.5 g of material.

[0095] Example 4 70 g of TPPO was charged into an autoclave. 360 g of toluene and 19 g of PMHS were added. The autoclave was closed, and the reaction mixture was heated to 170 °C. 7.5 g of the catalyst, Ti(OiPr)4, was dosed over 2 hours. After dosing was complete, the reaction mixture was cooled to 53 °C. The toluene was distilled off (more than 90% of the amount initially used). 170 g of iPrOH was added, and the reaction temperature was maintained at 60 °C until the solid dissolved. The reaction mixture was cooled to 0 °C, allowing the TPP to crystallize. The TPP was filtered off and washed with iPrOH. Finally, the TPP was dried to yield 33.6 g of material.

[0096] Example 5 75 g of TPPO was charged into a reactor, and 375 g of mesitylene was added. 41 g of PMHS and 7.7 g of Ti(OiPr)4 were added. The reaction mixture was heated to 150°C for 14 hours. The reaction mixture was then cooled to 90°C. Mesitylene was distilled off (more than 90% of the amount initially used). 180 g of iPrOH was added, and the reaction temperature was maintained at 60°C until the solid dissolved. The reaction mixture was cooled to 0°C to crystallize the TPP. The TPP was filtered off and washed with iPrOH. Finally, the TPP was dried to yield 55 g of material.

[0097] Example 6 235 g of TPPO waste containing 149.3 g of TPPO, methanol, and water was charged into a 2 L double-jacketed glass reactor. 720 g of mesitylene was added to the brownish solution. 162 g of a mixture of methanol, water, and mesitylene was distilled (800 to 160 mbar, 60 to 90 °C) until the KF was less than 0.1%. 15.4 g of Ti(OiPr)4, 79.9 g of PMHS, and 102 g of mesitylene were added to the suspension. The reaction mixture was heated to 170 °C (slight reflux) for 12 hours. The reaction mixture was then cooled to 60 °C. The crude solution was added over 2 hours to a second 2 L double-jacketed glass reactor, previously charged with 181 g of 45% w / w KOH. When hydrogen evolution ceased, stirring was stopped, but two phases were generated. 237 g of the aqueous phase was discharged. The organic phase was concentrated (50 to 10 mbar, 90°C) to give 142 g of an oily residue. 350 g of methanol was added and stirring was continued at 60°C for 1 hour. The temperature was reduced to 0°C within 2 hours and the slurry was filtered. The TPP was washed with 50 g of chilled methanol and dried to give 117 g of material.

[0098] Example 7 118 g of TPPO waste containing 75 g of TPPO, methanol, and water was charged into a 2 L double-jacketed glass reactor. 360 g of mesitylene was added to the brownish solution. 81 g of a mixture of methanol, water, and mesitylene was distilled (800 to 160 mbar, 60 to 90 °C) until the KF was less than 0.1%. 7.7 g of Ti(OiPr)4, 41 g of PMHS, and 51 g of mesitylene were added to the suspension. The reaction mixture was heated to 170 °C (slight reflux) for 12 hours. After that, the reaction mixture was cooled to 60 °C. The crude solution was added over 2 hours to a second 2 L double-jacketed glass reactor, previously charged with 100 g of 20% w / w KOH. When hydrogen evolution ceased, stirring was stopped, but two phases were generated. 119 g of the aqueous phase was discharged. The organic phase was concentrated (50 to 10 mbar, 90°C) to give 71 g of an oily residue. 180 g of iPrOH was added and stirring was continued at 60°C for 1 h. The temperature was reduced to 0°C within 2 h and the slurry was filtered. The TPP was washed with 50 g of chilled iPrOH and dried under vacuum to give 55 g of material.

[0099] Example 8 128 g of TPPO was charged into a 2 L double-jacketed glass reactor. To the yellow solution, 513 g of diethylbenzene (a mixture of o-, m-, and p-isomers) was added. To the suspension, 6.63 g of Ti(OiPr)4, 10.9 g of Zr(OnBu)4, and 67.9 g of PMHS were added. The reaction mixture was heated to 170 °C for 8 hours. The reaction mixture was then cooled to 100 °C, and the solvent was removed by distillation. The crude product was cooled to 50 °C, and 350 g of iPrOH was added and stirred until all solids were dissolved. The reaction mixture was slowly cooled and seeded. The temperature was further reduced to 0 °C, and the product TPP was filtered off and washed with 50 g of chilled iPrOH. The product was then dried under vacuum to yield 98 g of TPP.

[0100] Example 9 128 g of TPPO was charged into a 2 L double-jacketed glass reactor. To the yellow solution, 509 g of Solvesso 100 (solvent naphtha (petroleum) from Exxon Mobile) was added. To the suspension, 6.61 g of Ti(OiPr)4, 10.8 g of Zr(OnBu)4, and 67.8 g of PMHS were added. The reaction mixture was heated to 170 °C for 6 hours. The reaction mixture was then cooled to 120 °C, and the solvent was removed by distillation. The crude product was cooled to 50 °C, and 350 g of iPrOH was added and stirred until all solids were dissolved. The reaction mixture was slowly cooled and seeded. The temperature was further reduced to 0 °C, and the product TPP was filtered off and washed with 50 g of chilled iPrOH. The product was then dried under vacuum to yield 96 g of TPP.

[0101] Typical Example of Mother Liquor Treatment (Step 3): 500 g of water and 100 g of NH4OH 20% w / w are added to a reactor. The mixture is heated to 80°C and 100 g of the mother liquor obtained from the TPP filtration (Examples 1-5, 8, and 9) is added over 90 minutes. The reaction mixture is stirred for an additional hour. The white precipitate that forms is filtered off and dried to yield 18 g of material.

Claims

1. 1. A process for producing triphenylphosphine (compound of formula (I)), comprising: 【Chemistry 1】 First (Step 1), triphenylphosphine oxide (compound of formula (II)) 【Chemistry 2】 with formula (III) (CH) ３ ) ３ Si-O- (CH) ３ (H)Si-O) ｎ -Yes (CH) ３ ) ３ (III) (wherein n is a value between 10 and 100,000) and a compound of Formula (IV) 【Transformation 3】 (wherein M is titanium (Ti), zirconium (Zr), or a mixture thereof; R, R １ , R ２ and R ３ are, independently of each other, OR ４ and In the formula, R ４ is a linear or branched C １ -C ６ alkyl group) In the presence of at least one catalyst reacting in at least one aromatic solvent and / or at least one alkane at elevated temperature; In the second step (step 2), Formula (V) R ５ -OH(V) (In the formula, R ５ is a linear or branched C １ -C ６ alkyl moiety) adding at least one alcohol to the reaction mixture.

2. The at least one aromatic solvent may be benzene, one or more C １ -C ４ - Benzene substituted with alkyl groups and one or more OC １ -C ４ - benzene substituted with an alkyl group, or mixtures thereof, or the at least one alkane may be linear, branched or cyclic, or mixtures thereof. ４ -C １８ The process of claim 1 wherein the solvent is an alkane.

3. 3. The process of claim 1 or 2, wherein the catalyst in step 1 is a mixture of compound (IV) where M is titanium and compound (IV) where M is zirconium.

4. 4. The process of claim 3, wherein the ratio of compound (IV) where M is titanium to said compound (IV) where M is zirconium, (IV)-Ti:(IV)-Zr, is from 1:99 to 99:1, preferably said ratio is from 20:80 to 80:20, most preferably from 40:60 to 60:

40.

5. 5. The process according to any one of claims 1 to 4, wherein the compound of formula (III) is added in an amount of 1.0 to 4 molar equivalents (calculated relative to the active hydrogen content of PMHS relative to the amount of TPPO).

6. The compound R of formula (IV) ４ is a linear or branched C １ -C ６ -alkyl, preferably R of said compound of formula (IV) ４ The process of any one of claims 1 to 5, wherein is selected from the group consisting of ethyl, iso-propyl, n-propyl, iso-butyl, and n-butyl.

7. When a mixture of compounds (IV) is used, R ４ The process according to any one of claims 3 to 6, wherein is different in compound (IV)-Zr and in compound (IV)-Ti.

8. The process according to any one of claims 1 to 7, wherein the compound of formula (IV) is used in an amount of 1 to 20 mol % (relative to the amount of TPPO).

9. The process of any one of claims 1 to 8, wherein step 1 is carried out at a temperature of from 100°C to 200°C.

10. After step 1, the solvent or the mixture of solvents is removed (completely or partially) from the reaction mixture; In the alcohol of formula (V), R ５ is a linear or branched C １ -C ４ is an alkyl moiety, or preferably R ５ is branch C １ -C ６ 10. The process of any one of claims 1 to 9, wherein the alcohol of formula (V) is an alkyl moiety, or more preferably, is isopropanol (iPrOH).

11. The process of any one of claims 1 to 10, wherein the at least one alcohol of formula (V) is added to the reaction mixture in molar excess (relative to TPPO).

12. In the third step (step 3), the mother liquor (obtained after step 2) is treated with ammonium hydroxide, preferably in the amount of H ２ NH in O ３ The process of any one of claims 1 to 11, wherein the concentration is from 1 to 30% by weight.

13. 14. The process of claim 12 or 13, wherein step 3 is carried out at a temperature of from 40°C to 120°C, and step 3 is preferably carried out in the presence of at least one surfactant.

14. 1. A method for producing carotenoids, comprising: i) producing TPP from waste containing TPPO according to any one of claims 1 to 13; ii) subjecting each carotenoid constituent compound to a coupling reaction with the TPP as a coupling reagent produced according to the above step i); iii) recovering said respective carotenoids; A method comprising:

15. A carotenoid obtained by the method of claim 14.

16. 16. Use of triphenylphosphine (TPP) produced by the process of any one of claims 1 to 15 for the production of a carotenoid selected from the group of carotenoids comprising α-, β-, γ- or δ-carotene, apocarotenal, β-apo-8'-carotenal, β-apo-12'-carotenal, lycopene, bixin, or selected from the group of carotenoids comprising lutein, astaxanthin, canthaxanthin, citranaxanthin, cryptoxanthin, flavoxanthin, violaxanthin, or zeaxanthin.

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