NZ503427A

NZ503427A - Preparing di, tri or polyalcohol from formaldehyde and second aldehyde via Cannizzaro process

Info

Publication number: NZ503427A
Application number: NZ50342700A
Authority: NZ
Inventors: Nicola Rehnberg
Original assignee: Perstorp Ab
Priority date: 1999-03-31
Filing date: 2000-03-15
Publication date: 2001-08-31
Also published as: AU4155500A; SE9901172L; SE520963C2; WO2000058246A1; AU3991500A; WO2000058247A1; SE9901172D0

Abstract

A process for preparation of a di, tri or polyalcohol from formaldehyde and a second aldehyde in the presence of an alkaline catalyst. The process comprises an aldol condensation and a subsequent crossed Cannizzaro reaction. The process is characterised by a formaldehyde reduced and a formate reduced or formate free process for the production of a di, tri or polyalcohol when the crossed Cannizzaro reaction is interrupted when less than the equivalent amount of formate is generated and obtained reaction mixture is subjected to a subsequent transfer hydrogenation. Less formaldehyde and less OH- are required in the Cannizzaro reaction. The Cannizzaro reaction comprises reacting a methylolaldehyde with formaldehyde at a molar ratio of 1:0.3-0.9 in the presence of 0.3-0.9 mole of OH-. The Cannizzaro reaction is interrupted when 0.2-0.8 mole of HCOO- is generated.

Description

Patents Form 5 503427 N.Z. No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION A FORMALDEHYDE AND FORMATE REDUCED POLYPOL PROCESS We, PERSTORP AB, a Swedish Company of, S-284 80 Perstorp, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- 1 A A FORMALDEHYDE AND FORMATE REDUCED POLYOL PROCESS The present invention refers to a novel formaldehyde and formate reduced process for preparation of a di, tri or polyalcohol from formaldehyde and a second aldehyde in the presence of an alkaline catalyst. The process comprises an aldol condensation and a subsequent crossed Cannizzaro reaction. The Cannizzaro reaction is interrupted when less than one equivalent of formate is generated. The obtained reaction mixture is in a subsequent step subjected to a transfer hydrogenation in the presence of an effective amount of a proper transfer hydrogenation catalyst.

Di, tri and polyalcohols having for instance a neopentyl structure, such as neopentyl glycol, 2-ethyl-2-butyl-l,3-propandediol, trimethylolethane, trimethylolpropane and pentaerythritol are normally synthesised in an alkali catalysed aldol condensation of formaldehyde and a second aldehyde yielding a methylolaldehyde. Said methylolaldehyde is in a subsequent step reduced to corresponding alcohol by means of a so called crossed Cannizzaro reaction with a further equivalent of formaldehyde in the presence of a strong base, such as an alkali or alkaline earth metal hydroxide, an amine or other compound producing OH®. The reaction can alternatively be carried out by means of catalytic hydration. The synthesis as well as recovery of obtained reaction product normally yield secondary products such as formates and acetals. This kind of synthesis can be exemplified by commonly used synthetic methods for producing di, tri and tertrahydric alcohols such as pentaerythritol, trimethylolpropane, neopentyl glycol and 2-ethyl-2-butyl-l ,3-propanediol.

Pentaerythritol can for instance be synthesised in an aldol condensation according to above, wherein 3 moles of formaldehyde and 1 mole of acetaldehyde are reacted to yield trimethylol-acetaldehyde, followed by a crossed Cannizzaro reaction with 1 further mole of formaldehyde in the presence of 1 mole of OHe in the form of for instance potassium, sodium or calcium hydroxide or carbonate. The synthesis yields pentaerythritol and formate, such as potassium, sodium or calcium formate, and as secondary product or products minor amounts of for instance one or more pentaerythritolformals (formal = formaldehyde acetal).

Trimethylolpropane is synthesised in accordance with above in an aldol condensation of 2 moles of formaldehyde and 1 mole of n-butyraldehyde and by reduction of obtained methylolaldehyde by means of 1 further mole of formaldehyde in a subsequent crossed Cannizzaro reaction.

Neopentyl glycol is synthesised in accordance with above by aldol condensation of 1 mole of formaldehyde and 1 mole of isobutyraldehyde yielding hydroxypivaldehyde, which methylol- aldehyde subsequently in a crossed Cannizzaro reaction is reduced by means of 1 further mole of formaldehyde. 2-ethyl-2-butyl-1,3-propanediol is synthesised as neopentyl glycol with the difference that isobutyraldehyde is replaced by 2-ethyl-hexanal.

The reactions taking place in above well known processes can, taking neopentyl glycol as an example, be summarised Aldol condensation: (CH3)2CHCHO + HCHO HOCH2(CH3)2CCHO Cannizzaro reaction: HOCH2(CH3)2CCHO + HCHO + OH0 > (CH3)2C(CH2OH)2 + HCOO0 Balanced formula: (CH3)2CHCHO + 2 HCHO + OH0 (CH3)2C(CH2OH)2 + HCOO0 Above schemes are valid for other di, tri and polyalcohols by proper replacement of the number of formaldehyde moles and proper choice of second aldehyde in the aldol reaction and accordingly yielded methylolaldehyde in the aldol condensation as well as in the Cannizzaro reaction.

The mechanisms behind aldolisation and cannizzarisation are since long well known in the art. The kinetics of said reactions, various processes for industrial production and recovery, reaction parameters and the like are thoroughly disclosed and discussed in a large number of handbooks, patents and other publications, such as Kirk-Othmer "Encyclopedia of Chemical Technology" 3rd. Ed. Vol. 1, 1978 "Alcohols, Polyhydric", pp. 755-789 (incl. Bibliography), "Studies on Intermediates Involved in the Synthesis of Pentaerythritol and Related Alcohols" Parts I-VI, Jan-Erik Vik, Acta Chemica Scandinavia 26-28 (1972-74), and "Syntes av 2-Etyl-2-Butyl-l,3-Propandiol", Mikael Karlsson, 900202, Royal Institute of Technology, Stockholm, Sweden. A selection of published Patents and Patent Applications will cover most of the 20th century and will from the 1940's to present day include publications such as German Patent 733 849, US Patent 2,170,624, US Patent 2,790,837, European Patent 0 343 475, European Patent Application 0 708 073 relating to a process using a carbonate as alkaline catalyst, US Patent 5,841,002 relating to a process wherein the alkaline catalyst is recovered and recycled and the International Patent Application W099/35112 relating to a process for preparation of neopentyl glycol by hydrogenation of hydroxypivaldehyde in the presence of hydrogen, a nickel catalyst and an aliphatic alcohol or ether.

The present invention provides quite surprisingly a formaldehyde reduced and formate reduced or formate free process for production of a di, tri or polyalcohol. The crossed Cannizzaro reaction is interrupted when less than equivalent amount of formate is generated and obtained reaction mixture is subjected to a subsequent transfer hydrogenation. Less formaldehyde and less OH® are thus required in said Cannizzaro reaction and can accordingly be substantially reduced. In a reactor designed for aldol and Cannizzaro reactions, the aldol condensation is performed according to known methods and the Cannizzaro reaction is terminated when for instance half a mole of formate on one mole of methylolaldehyde is generated. The reaction mixture is then subjected to a transfer hydrogenation, which for instance can be performed by pumping the reaction mixture through a column filled with a proper transfer hydrogeneration catalyst. Embodiments of the present invention include that HCOO® prior to said transfer hydrogenation optionally is added to the reaction mixture, obtained from the crossed Cannizzaro reaction, in an amount giving a molar ratio methylolaldehyde to HCOO® of 1:0.8-1.2.

A balanced formula, corresponding to the previously disclosed balanced neopentyl glycol formula and using for instance Pd/C (palladium on activated carbon) as transfer hydrogenation catalyst, for a process according to the present invention can for instance be disclosed as follows Example of blanced formula according to the present invention: Pd/C (CH3)2CHCHO + VA HCHO + '/2 Na2C03 + H20 (CH3)2C(CH2OH)2 + NaHC03 Formate salts decompose on a catalyst surface to give hydrogen and hydrogen carbonate as m below scheme using sodium species and a Pd/C (palladium on activated carbon) catalyst as example Pd/C HCOONa + H20 H2 (g) + NaHC03 In the presence of reducible functions, the in situ formed hydrogen is transferred to the substrate and not lost as hydrogen gas, which for instance can be exemplified by below simplified scheme H2(Pd) + C=0 CH-OH Hydrogen carbonate formed in the transfer hydrogenation may be calcined to give corresponding carbonate and recirculated into the process as said alkaline catalyst.

Above schemes are valid for other di, tri and polyalcohols, using a proper second aldehyde and a proper molar ratio between formaldehyde and said second aldehyde. The advantages and savings are obvious when a balanced formula according to the present invention and a balanced formula according to said known process are compared. Further advantages include that hydrogen carbonate, such as potassium or sodium hydrogen carbonate, formed in the crossed Cannizzaro reaction may be calcined to give carbonates being bases strong enough to substitute for instance alkali or alkaline earth metal hydroxides.

The state of the art in catalytic transfer hydrogenation is excellently and thoroughly disclosed and discussed in "Heterogeneous Catalytic Transfer Hydrogenation and Its Relation to Other Methods for Reduction of Organic Compounds", by Robert A.W. Johnstone et al and published in Chem. Rev. 1985, 85, pp. 129-170.

The present invention accordingly refers to a formaldehyde and formate reduced or formate free process for preparation of a di, tri or polyalcohol from formaldehyde and a second aldehyde in the presence of an effective amount of at least one alkaline catalyst, such as an alkali or alkaline earth metal hydroxide or carbonate and/or an amine. The process comprises the step of aldol condensation yielding a methylolaldehyde and a subsequent crossed Cannizzaro reaction yielding said di, tri or polyalcohol and formate, whereby said Cannizzaro reaction comprises reacting said methylolaldehyde with formaldehyde at molar ratio said methylolaldehyde to said formaldehyde of 1 to less than 1, such as 1:0.3-0.9, mole in the presence of less than 1, preferably 0.3-0.9, mole of OH® on 1 mole of said methylolaldehyde. The OH® is in preferred embodiments of the present invention derived from potassium, sodium and/or calcium carbonate and/or hydroxide. The OH® is suitably also or alternatively derived from an amine, such as triethylamine. The Cannizzaro reaction is interrupted when 0.2-0.8, such as 0.4-0.6, mole of HCOO® (formate ions) is generated on 1 mole of said methylolaldehyde and obtained reaction mixture is in a subsequent step subjected to a transfer hydrogenation in the presence of an effective amount of at least one transfer hydrogenation catalyst. The transfer hydrogenation yields said di, tri or polyalcohol and hydrogen carbonate from said methylolaldehyde and formate. The process of the present invention is suitably either a batch or a continuous process.

The second aldehyde is in preferred embodiments of the present invention an aliphatic aldehyde of formula Ri—C—CHO I R3 wherein Rj, R2 and R3 independently is hydrogen or a linear or branched alkyl having 1-22 carbon atoms with the proviso that the aliphatic aldehyde has at least 3, such as 3-24, carbon atoms. Especially preferred embodiments of said second aldehyde include acetaldehyde, n-butyraldehyde, isobutyraldehyde, propionaldehyde, hexanal, 2-ethylhexanal, valeraldehyde, isovaleraldehyde, octanal and decanal. Further suitable second aldehydes not included in said formula can be exemplified by for instance cyclohexanecarboxaldehyde, phenylacetaldehyde, succinic dialdehyde and adipic dialdehyde.

The Cannizzaro reaction of the present process is preferably performed at a temperature of 0-120°C, such as 10-60°C, in the presence of 0.2-0.8, preferably 0.4-0.6, mole of OH® on 1 mole of said methylolaldehyde and is accordingly interrupted when said molar amount of HCOO® is generated on 1 mole of said methylolaldehyde. The Cannizzaro reaction thus comprises reacting said methylolaldehyde with said formaldehyde at a molar ratio methylolaldehyde to formaldehyde of 1:0.2-0.8, preferably 1:0.4-0.6.

In certain embodiments of the present invention, HCOO® is prior to said transfer hydrogenation optionally added to the reaction mixture, obtained from the crossed Cannizzaro reaction, in an amount giving a molar ratio methylolaldehyde to HCOO® of 1:0.8-1.2 in the reaction mixture.

The transhydrogenation of the present process is preferably performed at a temperature of 0-100°C, such as 10-80°C, 20-60°C or most preferably 30-50°C, and in the presence of at least one heterogeneous and/or at least one homogeneous metal or metal comprising catalyst, such as a catalyst comprising at least one metal on activated carbon. Suitable metals are found among for instance palladium, ruthenium, rhodium, iridium, osmium, molybdenum, rhenium, tungsten, cobalt, iron and nickel as well as combinations thereof and therewith.

The di, tri or polyalcohol prepared by the process of the present invention is in especially preferred embodiments a 2-alkyl-l,3-propanediol, a 2,2-dialkyl-l,3-propanediol, a 2-hydroxyalkyl-1,3-propanediol, a 2-alkyl-2-hydroxyalkyl-1,3-propanediol, or a 2,2-di(hydroxyalkyl)-l,3-propanediol, whereby said alkyl preferably is linear or branched alkanyl having for instance 1 to 8 carbon atoms. These alcohols can suitably be exemplified by for instance neopentyl glycol, 2-ethyl-2-butyl-l,3-propanediol, trimethylolethane, trimethylolpropane and pentaerythritol.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilise the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever. It will be understood, of course, that the invention is not limited thereto since many modifications, such as the choice of second aldehyde, molar ratio formaldehyde to second aldehyde, reaction temperatures etc., may be made, and it is, therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention. In the following examples, Example 1 and 2 show embodiments of the process, according to the present invention, for synthesis of neopentyl glycol. Example 3 is a comparative example showing a typical process for synthesis of neopentyl glycol, which process comprises the steps of aldol and crossed Cannizzaro reaction. Results obtained in Examples 1-??? are given in Table I.

Example 1 3.45 moles of formaldehyde (27% aq.), 0.23 mole of K2CO3 and 929.9 g of water were charged and mixed in a reactor at a temperature of 20°C. Subsequent the mixing, 2.30 moles of isobutyraldehyde (98.7%) were during 140 minutes charged at said 20°C. The temperature m the reaction mixture was after 2 hours of aldolisation raised to 30°C and maintained for 19 hours. The reaction mixture was then cooled to 20°C and 0.92 mole of KOH (20% aq.) was charged. The temperature was now raised to 50°C for crossed cannizzarisation and kept at said temperature. By control over stoechiometry and temperature the cannizzarisation was terminated when lA equivalent of neopentyl glycol was generated. 5% by weight of a Pd/C (5% palladium on activated carbon) catalyst was now charged for transfer hydrogenation. The reaction mixture was stirred at said 50°C until said transfer hydrogenation was completed.

Example 2 3.45 moles of formaldehyde (27% aq.), 0.23 mole of K2CO3 and 929.9 g of water were charged and mixed in a reactor at a temperature of 20°C. Subsequent the mixing, 2.30 moles of isobutyraldehyde (98.7%) were during 140 minutes charged at said 20°C. The temperature in the reaction mixture was after 2 hours of aldolisation raised to 30°C and maintained for 19 hours. The reaction mixture was then cooled to 20°C and 0.92 mole of KOH (20% aq.) was charged. The temperature was now raised to 50°C for crossed cannizzarisation and kept at said temperature. By control over stoechiometry and temperature the cannizzarisation was terminated when Vi equivalent of neopentyl glycol was generated. The reaction mixture was subsequently cooled to room temperature and 5% by weight of a Pd/C (5% palladium on activated carbon) catalyst was now charged for transfer hydrogenation. The reaction mixture was stirred at room temperature until said transfer hydrogenation was completed.

Example 3 (comparative) 3.4 moles of formaldehyde (27% aq.), 1.7 mole of KOH and 930 g of water were charged and mixed in a reactor at a temperature of 20°C. Subsequent the mixing, 1.6 mole of isobutyraldehyde (98.7%) were during 10 minutes charged at said 20°C. The temperature m the reaction mixture was 25 mmutes after addition of isobutyraldehyde raised to 55°C and maintained until the aldolisation and the crossed cannizzarisation were completed. The synthesis was now terminated by neutralisation with sulphuric acid.

Table I Examples 1 and 2 *] Example 3 Charged formaldehyde on 1 mole of charged isobutyraldehyde: 1.50 mole 2.20 mole Charged potassium hydroxide on 1 mole of isobutyraldehyde: 0.40 mole 1.06 mole Consumed formaldehyde on 1 mole of charged isobutyraldehyde: 1.47 mole 2.01 mole Neopentyl glycol formed in the Cannizzaro reaction: 80% 100% Neopentyl glycol formed in the transfer hydrogenation: % — Formate generated on 1 mole of charged formaldehyde: < 0.01 mole 0.4 mole *2 Mean values of figures obtained in Examples 1 and 2. *2 Mean value of figures obtained in repeated syntheses. 8

Claims

WHAT WE CLAIM IS:

1. A process for preparation of a di, tri or polyalcohol from formaldehyde and a second aldehyde in the presence of at least one alkaline catalyst, said process comprising aldol condensation yielding a methylolaldehyde and a subsequent crossed Cannizzaro reaction yielding said di, tri or polyalcohol and formate characterised in, that said Cannizzaro reaction comprises reacting said methylolaldehyde with formaldehyde at a molar ratio said methylolaldehyde to said formaldehyde of 1:0.3-0.9 in the presence of 0.3-0.9 mole of OH0 on 1 mole of said methylolaldehyde, that said Cannizzaro reaction is interrupted when 0.2-0.8 mole of HCOO® is generated on 1 mole of said methylolaldehyde and that obtained reaction mixture in a subsequent step is subjected to a transfer hydrogenation in the presence of an effective amount of at least one transfer hydrogenation catalyst, which transfer hydrogenation yields said di, tri or polyalcohol and hydrogen carbonate.

2. A process according to Claim 1 characterised in, that HCOO® prior to said transfer hydrogenation is added to the reaction mixture, obtained from the crossed Cannizzaro reaction, in an amount giving a molar ratio methylolaldehyde to HCOO® of 1:0.8-1.2.

3. A process according to Claim 2 characterised in, that said HCOO® is derived from an alkali metal or alkaline earth metal formate.

4. A process according to any of the Claims 1-3 characterised in, that said Cannizzaro reaction is interrupted when 0.4-0.6 mole of HCOO® is generated on 1 mole of said methylolaldehyde.

5. A process according to Claim 4 characterised in, that said alkali or alkaline earth metal formate is potassium, sodium and/or calcium formate.

6. A process according to any of the Claims 1-4 characterised in, that said second aldehyde is an aliphatic aldehyde of formula Rj—C—CHO I r3 wherein Ri, R2 and R3 independently is hydrogen or a linear or branched alkyl having 1-22 carbon atoms with the proviso that the aliphatic aldehyde has at least 3 carbon atoms. 9

7. A process according to any of the Claims 1-6 characterised in, that said second aldehyde is acetaldehyde, n-butyraldehyde, isobutyraldehyde, propionaldehyde, hexanal, 2-ethylhexanal, valeraldehyde, isovaleraldehyde, octanal or decanal.

8. A process according to any of the Claims 1-7 characterised in, that said at least one alkaline catalyst compnses at least one alkali metal or alkaline earth metal hydroxide or carbonate.

9. A process according to Claim 8 characterised in, that said alkali or alkaline earth metal is potassium, sodium and/or calcium.

10. A process according to any of the Claims 1-7 characterised in, that said at least one alkaline catalyst comprises at least one amine.

11. A process according to Claim 10 characterised in, that said amine is tnethylamine.

12. A process according to any of the Claims 1-11 characterised in, that said Cannizzaro reaction is performed at a temperature of 0-120°C

13. A process according to Claim 10 characterised in, that said Cannizzaro reaction is performed at 10-60°C.

14. A process according to any of the Claims 1-13 characterised in, that said OH® during said Cannizzaro reaction is present in an amount of 0.4-0.6 mole on 1 mole of methylolaldehyde.

15. A process according to any of the Claims 1-14 characterised in, that said OH® at least partly is derived from at least one alkali or alkaline earth metal hydroxide or carbonate.

16. A process according to Claim 15 characterised in, that said alkali or alkaline earth metal is potassium, sodium and/or calcium.

17. A process according to any of the Claims 1-14 characterised in, that said OH® at least partly is derived from at least one amine.

18. A process according to Claim 17 characterised in, that said amine is triethylamine.

19. A process according to any of the Claims 1-18 characterised in, that said Cannizzaro reaction comprises reacting said methylolaldehyde with said formaldehyde at a molar ratio methylolaldehyde to formaldehyde of 1:0.4-0.6. 10

20. A process according to any of the Claims 1-19 characterised in, that said transfer hydrogenation is performed at 0-100°C.

21. A process according to Claim 20 characterised in, that said transfer hydrogenation is performed at 10-80°C.

22. A process according to Claim 20 characterised in, that said transfer hydrogenation is performed at 20-60°C.

23. A process according to Claim 20 characterised in, that said transfer hydrogenation is performed at 30-50°C.

24. A process according to any of the Claims 1-23 characterised in, that said transfer hydrogenation catalysts is at least one heterogeneous and/or homogeneous metal or metal comprising catalyst.

25. A process according to Claim 24 characterised in, that said transfer hydrogenation catalyst comprises at least one metal on activated carbon.

26. A process according to Claim 24 or 25 characterised in, that said catalyst comprises palladium, ruthenium, rhodium, iridium, osmium, molybdenum, rhenium, tungsten, cobalt, iron and/or nickel.

27. A process according to any of the Claims 1-26 characterised in, that said di, tri or polyalcohol is a 2-alkyl-1,3-propanediol, a 2,2-dialkyl-l,3-propanediol, a 2-hydroxyalkyl-l,3-propanediol, a 2-alkyl-2-hydroxyalkyl-l,3-propanediol or a 2,2-di(hydroxyalkyl)-1,3-propanediol.

28. A process according to Claim 27 characterised in, that said alkyl is linear or branched alkanyl having 1-8 carbon atoms.

29. A process according to any of the Claims 1-28 characterised in, that said di, tri or polyalcohol is neopentyl glycol, 2-ethyl-2-butyl-l,3-propanediol, trimethylolethane, trimethylolpropane or pentaerythritol.

30. A process according to any of the Claims 1-29 characterised in, that hydrogen carbonate yielded in said transfer hydrogenation is calcined to give corresponding carbonate, recycled and used as said alkaline catalyst. 11

31. A process according to claim 1 substantially as herein described or exemplified. END OF CLAIMS intellectual property office of n.z. - 7 JUN 2001 received PERSTORP AB By Their Attorneys HENRY HUGHES Per:£3C_ ^ ■ - - — END