WO2017196225A1

WO2017196225A1 - Process for production of mixed 2,2-dialkyl-1,3-propanediols

Info

Publication number: WO2017196225A1
Application number: PCT/SE2017/050386
Authority: WO
Inventors: Konstantin MPAMPOS; Thomas Andersson
Original assignee: Perstorp AB
Current assignee: Perstorp AB
Priority date: 2016-05-12
Filing date: 2017-04-20
Publication date: 2017-11-16
Anticipated expiration: 2018-11-12
Also published as: CN109153624A; CN109153624B; SE1630105A1; EP3455200A1; EP3455200A4

Abstract

Disclosed is a process for production of mixed 2,2-dialkyl-1,3-propanediols by aldol reaction and subsequent crossed cannizzaro reaction, whereby formaldehyde in presence of a strong base is subjected to aldol reaction and subsequent cannizzaro reaction with 2-methylpropanal and at least one other 2-alkylalkanal. Said 2-methylpropanal and said at least one other 2-alkylalkanal are present in a weight ratio of 60-95% by weight of 2-methylpropanal and 5-40% by weight of said at least one other 2-alkylalkanal and said process yields a corresponding mixture of 2,2- dimethyl-1,3-propanediol and at least one other 2,2-dialkyl-1,3-propanediol.

Description

PROCESS FOR PRODUCTION OF MIXED 2,2-DIALKYL-l,3-PROPANEDIOLS

The present invention relates to a process for production of mixed 2,2-dialkyl-l,3-propanediols wherein formaldehyde in presence of a base is subjected to aldol reaction and subsequent crossed cannizzaro reaction with 2-methylpropanal and at least one other 2-alkylalkanal yielding a mixture of 2,2-dimethyl-l,3-propanediol and at least one other 2,2-dialkyl-l,3-propanediol.

Diols having for instance a neopentyl structure, such as 2,2-dialkyl-l,3-propanediols, are typically synthesised in an alkali catalysed aldol condensation, at for instance 30-60°C, of formaldehyde and a second aldehyde yielding a methylolaldehyde. Said methylolaldehyde is in a subsequent step reduced, at a temperature of for instance 60-90°C, to corresponding diol 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 ΟΗ^ς. The aldol and cannizzaro reactions are typically performed at a pH of 8-12. The cannizzaro reaction can alternatively be replaced by catalytic hydrogenation. The synthesis as well as recovery of obtained reaction product normally yield secondary products such as formates and acetals.

The reactions taking place in above processes can, taking 2,2-dimethyl-l,3-propanediol (neopentyl glycol) as an example, be summarised

Aldol condensation:

(CH₃)₂CHCHO + HCHO *^■ HOCH₂(CH₃)₂CCHO

Cannizzaro reaction:

HOCH₂(CH₃)₂CCHO + HCHO Θ *► (CH₃)₂C(CH₂OH)₂ + HCOO ,Θ

Balanced formula:

(CH₃)₂CHCHO + 2 HCHO Θ *► (CH₃)₂C(CH₂OH)₂ + HCOO ,Θ

Above schemes are valid for other 2,2-dialkyl-l,3-propanediols, such as 2-butyl-2-ethyl-l,3- propanediol, by proper replacement and choice of the second aldehyde and accordingly yielded methylolaldehyde in the aldol condensation. The mechanisms behind aldolisation and cannizzarisation are since long well known in the art and 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, patent applications and other publications, such as Kirk-Othmer "Encyclopedia of Chemical Technology" 3^rd. 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, 1990-02-02, 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 2,135,063, US Patent 2, 468,718, US Patent 2,790,837, published International Application WO2008/091186, European Patent 0 343 475, European Patent 0 708 073, US Patent 5,841,002 and US Patent 8,519,084 teaching processes for production of diols via either hydrogenation of unsaturated aldehydes (alkenals) followed by cannizzarisation of yielded saturated aldehydes (alkanals) or aldolisation of unsaturated aldehydes (alkenals) followed by hydrogenation of yielded unsaturated hydroxy aldehydes (hydroxy alkenals), thus yielding saturated diols.

Diols, such as said 2,2-dialkyl-l,3-propanediols, are frequently used as raw materials in production of for instance polyesters, including alkyd resins, polycarbonates and poly(alkylene phthalates), polyethers and polyurethanes for various applications, such as decorative and protective coatings, adhesives, synthetic lubricants, plasticisers, performance additives, PET containers, foams, elastomers, synthetic fibres and the like as disclosed in a large number of theses and handbooks on diol/polyol comprising applications. It is furthermore common to mix two or more 2,2-dialkyl-l,3-propanediols, with for instance varying alkyl chain lengths, to obtained certain and desired product properties, such as hardness, flexibility, transparency, temperature stability and the like. There accordingly exists a certain desire and need for mixed 2,2-dialkyl-l,3-propanediols as a single product instead of mixing two or more diols. The present invention provides the major advantage of providing a ready for use diol mixture. The process of the present invention gives high yields of two or more 2,2-dialkyl-l,3-propanediols in a single reactor/production plant and quite unexpectedly do not give any cross-aldol coupling of the substrate aldehydes, that is 2-methylpropanal and said at least one other 2-alkylalkanal. A further major advantage is that yielded 2,2-dialkyl-l,3-propanediols are produced as a mixture and can be supplied as such thus reducing the number a compounds necessary to store and/or ship by the producer and/or end user. Yet a further and major advantage is that said two or more 2,2-dialkyl-l,3-propanediols can be produced simultaneously in the same reactor/production plant thus reducing for instance the number of and investments in reactors/production plants. Yielded 2,2-dialkyl-l,3-propanediol mixture can of course be separated into two or more single 2,2-dialkyl-l,3-propanediols by any method known in the art, such as distillation, fractionated crystallisation and the like.

The present invention accordingly refers to a process for production of mixed 2,2-dialkyl-l,3- propanediols by aldol reaction and subsequent crossed cannizzaro reaction wherein formaldehyde in presence of a strong base is subjected to aldol reaction and subsequent cannizzaro reaction with 2-methylpropanal and at least one other 2-alkylalkanal at a molar ratio formaldehyde to 2-methylpropanal and said at least one other 2-alkylalkanal of between 2-2.2: 1. 2-methylpropanal and said at least one other 2-alkylalkanal are, in embodiments of the present invention, preferably present in a weight ratio of between 99:1 and 1:99, such as between 60:40 and 95:5. Said as at least one other 2-alkylalkanal being other than 2-methylpropanal is in especially preferred embodiments, but not limited to, a 2-alkylbutanal, a 2-alkylpentanal, a 2- alkylhexanal, a 2-alkylheptanal and/or a 2-alkyloctanal, whereby said process yields a corresponding mixture of 2,2-dimethyl-l,3-propanediol (neopentyl glycol) and at least one other 2,2-dialkyl-l,3-propanediol. Said alkyl is in likewise especially preferred embodiments C₁-C₁2 linear or branched alkyl, such as methyl, ethyl, propyl, butyl or pentyl.

Said at least one other 2,2-dialkyl-l,3-propanediol is, but not limited to, in the most preferred embodiments of the present invention 2,2-diethyl-l,3-propanediol, 2,2-dibutyl-l,3-propanediol,

2.2- di(methylpropyl)-l,3-propanediol, 2-ethyl-2-methyl-l,3-propanediol, 2-propyl-2-methyl-

1.3 - propanediol and/or 2-butyl-2-ethyl-l,3-propanediol.

Said base utilised in the aldol and cannizzaro reactions of the present invention is suitably an alkali or alkaline earth metal hydroxide or carbonate and/or an amine, such as potassium, sodium and/or calcium hydroxide or carbonate and/or an amine, such as triethylamine. Said aldol reaction is preferably performed at a temperature of 30-60°C and said cannizzaro reaction is, likewise preferably, performed at 60-90°C and both reactions are suitably performed at a pH of for instance 8-12. The 2-methylpropanal and said at least one other 2-alkylalkanal can either be premixed prior to addition of formaldehyde and other reagents or charged separately and yielded 2,2-dimethyl-l,3-propanediol and yielded at least one other 2,2-dialkyl-l,3-propanediol can either be separated and on further processing be used as separate products or on further processing be used as a mixed product without any separation of resulting 2,2-dialkyl-l,3- propanediols. 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. In the following examples 1-6 are mixed 2,2-dimethyl-l,3-propanediol and 2-butyl-2-ethyl-l,3-propanediol produced at varying weight ratio 2-methylpropanal to 2-ethylhexanal.

Example 1

A reaction solution comprising 101.9 parts by weight of an aldehyde mixture consisting of 95% by weight of 2-methylpropanal and 5% by weight of 2-ethylhexanal, 180.7 parts by weight of 48% aq. formaldehyde, 121.1 parts by weight of 50% aq. sodium hydroxide and 650.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1047.9 parts by weight of a reaction mixture were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 8.4 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3-propanediol yield of 94.9% and a 2-butyl-2- ethyl-l,3-propandiol yield of 91.9%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2-ethylhexanal and 0.6% of formaldehyde.

Experimental: 2-methylpropanal and 2-ethylhexanal were in said amounts premixed. The reactor was charged with the specified amount of water and formaldehyde and the mixture was under stirring adjusted 20°C over a period of 10 minutes. After said 10 minutes, charging of sodium hydroxide began followed by charging of the 2-methylpropanal/2-ethylhexanal mixture with a minute delay. Total charging time was 30 minutes. The temperature was set to increase from 20°C to 30°C during the same period. The temperature was after completed charging of reactants increased to 60°C over a period of 15 minutes followed by stirring at said temperature for a further 30 minutes. Yielded reaction mixture was, after completed reaction, cooled to a temperature of < 30°C and pH was adjusted by addition of formic acid. The reaction mixture was finally recovered, purified and analysed.

Example 2

A reaction solution comprising 107.2 parts by weight of an aldehyde mixture consisting of 90% by weight of 2-methylpropanal and 10% by weight of 2-ethylhexanal, 187.3 parts by weight of 48% aq. formaldehyde, 125.0 parts by weight of 50% aq. sodium hydroxide and 670.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1082.7 parts by weight of a reaction mixture were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 9.6 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3-propanediol yield of 91.3% and a 2-butyl-2- ethyl-l,3-propandiol yield of 90.6%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2-ethylhexanal and 0.7% of formaldehyde.

Experimental: As in Example 1.

Example 3

A reaction solution comprising 112.9 parts by weight of a mixture consisting of 85% by weight of 2-methylpropanal and 15% by weight of 2-ethylhexanal, 192.2 parts by weight of 48% aq. formaldehyde, 128.1 parts by weight of 50% aq. sodium hydroxide and 685.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1112.7 parts by weight of a reaction mixture were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 11.0 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3-propanediol yield of 98.1% and a 2-butyl-2-ethyl-l,3- propandiol yield of 95.1%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2-ethylhexanal and 0.8% of formaldehyde.

Experimental: As in Example 1.

Example 4

A reaction solution comprising 5.4 parts by weight of 2-ethylhexanal, 96.1 parts by weight of 2-methylpropanal, 181.0 parts by weight of 48% aq. formaldehyde, 121.2 parts by weight of 50% aq. sodium hydroxide and 650.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1047.2 parts by weight of a reaction mixture were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 10.9 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3- propanediol yield of 91.3% and a 2-butyl-2-ethyl-l,3-propandiol yield of 92.9%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2- ethylhexanal and 0.8% of formaldehyde.

Experimental: The reactor was charged with the specified amount of water, formaldehyde and 2-ethylhexanal and the mixture was under stirring adjusted 20°C over a period of 10 minutes. After said 10 minutes, charging of sodium hydroxide commenced followed by charging of the 2-methylpropanal with a minute delay. Total charging time was 30 minutes. The temperature was set to increase from 20°C to 30°C during the same period. The temperature was after completed charging of reactants increased to 60°C over a period of 15 minutes followed by stirring at said temperature for a further 30 minutes. Yielded reaction mixture was, after completed reaction, cooled to < 30°C and pH was adjusted by addition of formic acid. The reaction mixture was finally recovered, purified and analysed.

Example 5

A reaction solution comprising 11.2 parts by weight of 2-ethylhexanal, 96.2 parts by weight of 2-methylpropanal, 187.6 parts by weight of 48% aq. formaldehyde, 125.2 parts by weight of 50% aq. sodium hydroxide and 670.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1084.5 parts by weight of a reaction mixture were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 11.2 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3- propanediol yield of 97.2% and a 2-butyl-2-ethyl-l,3-propandiol yield of 96.6%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2- ethylhexanal and 1.4% of formaldehyde.

Experimental: As in Example 4.

Example 6

A reaction solution comprising 16.8 parts by weight of 2-ethylhexanal, 96.4 parts by weight of 2-methylpropanal, 192.5 parts by weight of 48% aq. formaldehyde, 128.8 parts by weight of 50% aq. sodium hydroxide and 685.0 parts by weight of water was subjected to aldol reaction and subsequent cannizzaro reaction. 1118.6 parts by weight of a reaction solution were, after completed reactions, isolated and the pH was adjusted to 5.5 by addition of 8.6 parts by weight of formic acid. The synthesis resulted, after recovery and purification, in a 2,2-dimethyl-l,3- propanediol yield of 97.9% and a 2-butyl-2-ethyl-l,3-propandiol yield of 95.1%. The amount of unreacted aldehydes was determined to be < 0.1% of 2-methylpropanal, < 0.1% of 2- ethylhexanal and 0.8% of formaldehyde.

Experimental: As in Example 4.

Claims

1. A process for production of mixed 2,2-dialkyl-l,3-propanediols by aldol reaction and subsequent crossed cannizzaro reaction characterised in, that formaldehyde in presence of a strong base is subjected to aldol reaction and subsequent cannizzaro reaction with 2- methylpropanal and at least one other 2-alkylalkanal at a molar ratio formaldehyde to 2- methylpropanal and said at least one other 2-alkylalkanal of 2-2.2:1, that 2-methylpropanal and said at least one other 2-alkylalkanal are present in a weight ratio of between 1 :99 and 99: 1 , such as between 60:40 and 95:5, and that said process yields a mixture of 2,2-dimethyl-l,3- propanediol and at least one other 2,2-dialkyl-l,3-propanediol.

2. A process according to Claim 1 characterised in, that said at least one other 2- alkylalkanal is a 2-alkylpropanal, a 2-alkylbutanal, a 2-alkylpentanal, a 2-alkylhexanal, a 2- alkylheptanal and/or a 2-alkyloctanal.

3. A process according to Claim 1 or 2 characterised in, that said alkyl is methyl, ethyl, propyl, butyl or pentyl.

4. A process according to any of the Claims 1-3 characterised in, that said at least one other 2,2-dialkyl-l,3-propanediol is 2,2-diethyl-l,3-propanediol, 2-ethyl-2-methyl-l,3- propanediol, 2-propyl-2-methyl-l,3-propanediol and/or 2-butyl-2-ethyl-l,3-propanediol.

5. A process according to any of the Claims 1-4 characterised in, that said base is an alkali or alkaline earth metal hydroxide or carbonate and/or an amine.

6. A process according to any of the Claims 1-5 characterised in, that said base is potassium, sodium and/or calcium hydroxide or carbonate.

7. A process according to any of the Claims 1-6 characterised in, that said aldol reaction is performed at a temperature of 30-60°C.

8. A process according to any of the Claims 1-7 characterised in, that said cannizzaro reaction is performed at 60-90°C.

9. A process according to any of the Claims 1-8 characterised in, that said aldol reaction and said cannizzaro reaction is performed at a pH of 8-12.

10. A process according to any of the Claims 1-9 characterised in, that 2- methylpropanal and said at least one other 2-alkylalkanal are mixed prior to addition of formaldehyde and other reagents.

11. A process according to any of the Claims 1-10 characterised in, that yielded 2,2-dimethyl-l,3-propanediol and yielded at least one other 2,2-dialkyl-l,3-propanediol are separated and on further processing used as separate products.

12. A process according to any of the Claims 1-10 characterised in, that yielded 2,2-dimethyl-l,3-propanediol and yielded at least one other 2,2-dialkyl-l,3-propanediol on further processing are used as a mixed product.