LEDERHOSE PAUL (DE)
CSIHONY SZILARD (DE)
| US6331656B1 | 2001-12-18 |
ISHIDO YASUSHI ET AL: "Well-Defined Alternating Copolymers of Benzaldehydes with Vinyl Ethers: Precision Synthesis by Cationic Copolymerization and Quantitative Degradation to Cinnamaldehydes", vol. 43, no. 7, 13 April 2010 (2010-04-13), US, pages 3141 - 3144, XP055879878, ISSN: 0024-9297, Retrieved from the Internet
ZHANG JINGHAN ET AL: "Characteristics and Mechanism of Vinyl Ether Cationic Polymerization in Aqueous Media Initiated by Alcohol/B(C6F5)3/Et2O", POLYMERS, vol. 11, no. 3, 1 March 2019 (2019-03-01), CH, pages 500, XP055879875, ISSN: 2073-4360, DOI: 10.3390/polym11030500
MACROMOLECULES, vol. 43, 2010, pages 3141 - 3144
MACROMOLECULES, vol. 45, 2012, pages 4060 - 4068
| Claims 1. Process for copolymerisation of at least one vinyl ether (V) and at least one aldehyde (A), optionally in the presence of at least one solvent, characterised in that the copolymerisa tion is carried out in the presence of at least one reactive boron trihalide complex of the formula BXs X x ROH wherein X is a halide, preferably selected from the group consisting of fluorine, chlorine, and bromine, more preferably selected from the group consisting of fluorine and chlorine, and especially fluorine, ROH is an alcohol or water, preferably an alkanol, more preferably a linear or branched Ci-Cio-alkanol, even more preferably a linear or branched Ci-C4-alkanol x is a positive number of more than 0 (zero) optionally in the presence of at least one Bronsted Acid (BA) and/or Lewis Base (LB), wherein the molar ratio of vinyl ethers (V) : aldehydes (A) is from 10 : 1 to 1 : 1, prefera bly from 7 : 1.2 to 1 : 1.2, more preferably from 5 : 1.2 to 1 : 1.2, even more preferably from 3 : 1.2 to 1 : 1.2, and especially from 2 : 1.2 to 1 : 1.2. 2. Process according to Claim 1 , wherein the alcohol ROH is selected from the group con sisting of methanol, ethanol, n-propanol, /so-propanol, n-butanol, and tert. butanol. 3. Process according to Claim 1 or 2, wherein the Bronsted Acid (BA) is selected from the group consisting of organic sulfonic acids and sulfuric acid, preferably sulfonic acids, more preferably aliphatic or aromatic sulfonic acids, even more preferably Ci- to C4-alkyl sulfonic acids, especially methane sulfonic acid and ethane sulfonic acid. 4. Process according to any of the Claims 1 to 3, wherein the Lewis Base (LB) is selected from the group consisting of ethers and esters, preferably aliphatic or cycloaliphatic ethers, more preferably selected from the group consisting of di(Cr to C4-alkyl) ethers, tetrahydrofurane, tetrahydropyrane, and dioxane, and especially selected from the group consisting of tetrahydrofurane, tetrahydropyrane, and dioxane. 5. Process according to any of the preceding claims, wherein the vinyl ethers (V) are Ci- to C2o-alkyl vinyl ethers, C3- to C2o-alkenyl vinyl ethers, C5- to Ci2-cycloalkyl vinyl ethers, cyclic vinylethers, such as 2,3-dihydrofuran, 3,4-dihydropyran, vinyl ethers comprising alkylene glycol side chains, vinyl ethers comprising ester groups in the side chain, and C6- to Ci2-aryl vinyl ethers, preferably Ci- to C2o-alkyl vinyl ethers, C3- to C2o-alkenyl vinyl ethers, and C5- to Ci2-cycloalkyl vinyl ethers, more preferably Ci- to C2o-alkyl vinyl ethers and C3- to C2o-alkenyl vinyl ethers, and especially Ci- to C2o-alkyl vinyl ethers. 6. Process according to any one of Claims 1 to 4, wherein the vinyl ethers (V) bear two or more vinyl ether groups. 7. Process according to any of the preceding claims, wherein the aldehyde (A) is selected from the group consisting of optionally substituted Ce- to Ci2-aromatic aldehydes, Ci- to Cioo-aliphatic aldehydes, one- or multifold unsaturated C3- to C2o-aliphatic aldehydes, preferably alpha, beta-unsaturated C3- to C2o-aliphatic aldehydes, and C5- to C12- cycloaliphatic aldehydes, preferably selected from the group consisting of optionally substituted Ce- to Ci2-aromatic aldehydes and Ci- to C2o-aliphatic aldehydes. 8. Process according to any of the preceding claims, wherein the copolymerisation is carried out at a temperature of from -90 to 0 °C, preferably from -80 to -20 °C, more preferably from -78 to -34 °C. 9. Process according to any of the preceding claims, wherein the copolymerisation is carried out for 0.5 to 24 hours, preferably 1 to 10 hours, and more preferably 1.5 to 7 hours. 10. Process according to any of the preceding claims, wherein the copolymerisation is stopped by quenching with alcohols, water, ammonia, amines, hydroxides, carbonates, and hydrogen carbonates. 11. Copolymer, comprising in polymerised form at least one vinyl ether (V) and at least one aldehyde (A), characterised in that the at least one aldehyde (A) is an aliphatic aldehyde, preferably a Ci- to Cioo-aliphatic aldehyde wherein the molar incorporation ratio of vinyl ethers (V) : aldehydes (A) is from 10 : 1 to 1 : 1, preferably from 7 : 1 to 1 : 1, more pref erably from 5 : 1 to 1 : 1 , even more preferably from 3 : 1 to 1 : 1 , and especially from 2 : 1 to 1 : 1. 12. Copolymer, comprising in polymerised form at least one vinyl ether (V) and at least one aldehyde (A), characterised in that the at least one vinyl ether (V) is a Cs- to C12- cycloalkyl vinyl ether, wherein the molar incorporation ratio of vinyl ethers (V) : alde hydes (A) is from 10 : 1 to 1 : 1, preferably from 7 : 1 to 1 : 1, more preferably from 5 : 1 to 1 : 1, even more preferably from 3 : 1 to 1 : 1, and especially from 2 : 1 to 1 : 1. 13. Copolymer, comprising in polymerised form at least one vinyl ether (V) and at least one aldehyde (A), characterised in that the at least one vinyl ether (V) is selected from the group consisting of C10- to C2o-alkyl vinyl ethers and C10- to C2o-alkenyl vinyl ethers, wherein the molar incorporation ratio of vinyl ethers (V) : aldehydes (A) is from 10 : 1 to 1 : 1 , preferably from 7 : 1 to 1 : 1 , more preferably from 5 : 1 to 1 : 1 , even more prefera bly from 3 : 1 to 1 : 1, and especially from 2 : 1 to 1 : 1. 14. Copolymer according to any of Claims 10 to 13, wherein the polydispersity is from 1 to 5, preferably from 1.1 to 3, more preferably from 1.2 to 2.5. 15. Copolymer according to any of Claims 10 to 14, wherein the weight average molecular weight Mw is from 1000 to 40000, preferably from 5000 to 30000, more preferably from 6000 to 25000 g/mol. 16. Process for hydrolysis of a copolymer according to any of the Claims 10 to 15, wherein the copolymer is optionally dissolved in at least one solvent and reacted with water in the presence of at least one Bronsted Acid with a pKa-value of not more than 3.0, more preferably not more than 2.0. |
Description
The present invention concerns a process for manufacturing of copolymers of aldehydes and vinyl ethers and certain copolymers of aldehydes and vinyl ethers.
Copolymers of aldehydes and vinyl ethers are known in the prior art, e.g. from results of the work group of Prof. Aoshima at Osaka University. In Macromolecules 2010, 43, 3141-3144 it is described how benzaldehydes and vinyl ethers are cationically copolymerised in the presence of GaC as Lewis Acid using ethane sulfonic acid as Bransted Acid.
It is a disadvantage of this process that GaCh is an expensive Lewis Acid and not available in industrial scale. In addition, the described process employs extensive drying of reagents before polymerisation. Drying towers and distillation of reagents are employed before copolymerisation is undertaken, most probably to ensure a low molecular weight distribution of the resulting pol ymers. Furthermore, the Macromolecules reference discloses only benzaldehyde and p- methoxy benzaldehyde as reactants and is silent about the use of other aldehydes.
From the same work group another Macromolecules reference was published (Macromolecules 2012, 45, 4060-4068) which discloses reaction of cycloaliphatic aldehydes, such as naturally occurring aldehydes. Furthermore, the use of FeCh/EtSChH and EtAICh/EtSChH as catalyst was disclosed, however, the reported conversion was low although the reaction time was 48 hours. In the prior art furthermore copolymerisation of furfural was disclosed, see Aso et al., Die Makromolekulare Chemie 1973, 172, 85. In this reference inter alia ?z»0{C, 2 \^ b ) is used as Lewis Acid for the polymerisation of furfural with e.g. 7-tolyl vinyl ether, however, the reaction is allegedly reported to occur under opening of the furan ring. Despite the long reaction time re ported, conversion rates are low and partly yield insoluble products. It was an object of the present invention to find reaction conditions under which aldehydes and vinyl ethers undergo reaction and according to which aldehydes other than aromatic or cycloali phatic aldehydes can be brought to reaction. Especially, a readily available Lewis Acid should be used together with a reaction time allowing an acceptable space-time-yield. In addition, the Lewis Acid used should be resilient so that there is no need to use dried reagents in the reac tion.
The object was achieved by a process for copolymerisation of at least one vinyl ether (V) and at least one aldehyde (A), optionally in the presence of at least one solvent, characterised in that the copolymerisation is carried out in the presence of at least one reactive boron trihalide com plex of the formula
BXs X x ROH wherein
X is a halide, preferably selected from the group consisting of fluorine, chlorine, and bromine, more preferably selected from the group consisting of fluorine and chlorine, and especially fluo rine,
ROH is an alcohol or water, preferably an alkanol, more preferably a linear or branched C1-C10- alkanol, even more preferably a linear or branched Ci-C4-alkanol x is a positive number of more than 0 (zero) optionally in the presence of at least one Bronsted Acid (BA) and/or Lewis Base (LB) wherein the molar ratio of vinyl ethers (V) : aldehydes (A) is from 10 : 1.2 to 1 : 1.2, preferably from 7 : 1.2 to 1 : 1.2, more preferably from 5 : 1.2 to 1 : 1.2, even more preferably from 3 : 1.2 to 1 : 1.2, and especially from 2 : 1.2 to 1 : 1.2.
It is an advantage compared to the documents pointed out above that the copolymerisation ac cording to the present invention takes place in the presence of a complex based on boron trihal ides as a Lewis Acid which is readily available even in industrial scale. Suitable boron trihalides are boron trifluoride, boron trichloride, and boron tribromide, preferably boron trifluoride and boron trichloride, and more preferably boron trifluoride.
The boron trihalides are used as a complex (BX 3 c x ROH) with at least one alcohol ROH or water, preferably one or two alcohols, and more preferably one alcohol.
In one embodiment of the present invention ROH may be water, i.e. R is hydrogen.
Alcohols ROH are selected from the group consisting of aliphatic, cycloaliphatic, and aromatic alcohols, preferably aliphatic or aromatic alcohols, and more preferably aliphatic alcohols.
The alcohol ROH may bear one or up to 4 hydroxy groups, preferably 1 to 3 hydroxy groups, more preferably 1 or 2 hydroxy groups, and especially 1 hydroxy group.
Aliphatic alcohols may be optionally substituted O to C2o-aliphatic alcohols, preferably O to C2o-alkanols, more preferably O to Cio-alkanols, even more preferably O to C 6 -alkanols, and especially preferably Ci- to C4-alkanols.
Cycloaliphatic alcohols may be optionally substituted C 5 - to Ci2-cycloaliphatic alcohols, prefera bly C 5 - to Ci2-cycloalkanols, more preferably C 5 - to Cycycloalkanols, and especially C 5 - to Ce- cycloalkanols.
Aromatic alcohols may be optionally substituted Ce- to Ci2-aromatic alcohols.
Examples for the above-mentioned alcohols are methanol, ethanol, n-propanol, isopropanol, n- butanol, sec-butanol, isobutanol, tert-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2- ethylhexanol, cyclohexanol, phenol, p-methoxyphenol, 0-, m- and p-cresol, benzyl alcohol, p- methoxybenzyl alcohol, 1- and 2-phenylethanol, 1- and 2-(p-methoxyphenyl)ethanol, 1-, 2- and 3-phenyl-1 -propanol, 1-, 2- and 3-(p-methoxyphenyl)-1 -propanol, 1- and 2-phenyl-2-propanol, 1- and 2-(p-methoxyphenyl)-2-propanol, 1-, 2-, 3- and 4-phenyl-1-butanol, 1-, 2-, 3- and 4-(p- methoxyphenyl)-1 -butanol, 1-, 2-, 3- and 4-phenyl-2-butanol, 1-, 2-, 3- and 4-(p-methoxy- phenyl)-2-butanol, 9-methyl-9H-fluoren-9-ol, 1,1-diphenylethanol, 1,1-diphenyl-2-propyn-1-ol, 1 ,1-diphenylpropanol, 4-(1 -hydroxy-1 -phenylethyl)benzonitrile, cyclopropyldiphenylmethanol, 1- hydroxy-1,1-diphenylpropan-2-one, benzilic acid, 9-phenyl-9-fluorenol, triphenylmethanol, di- phenyl(4-pyridinyl)methanol, alpha, alpha-diphenyl-2-pyridinemethanol, 4-methoxytrityl alcohol (especially polymer-bound as a solid phase), alpha-tert-butyl-4-chloro-4’-methylbenzhydrol, cy- clohexyldiphenylmethanol, alpha-(p-tolyl)-benzhydrol, 1,1,2-triphenylethanol, alpha, alpha- diphenyl-2-pyridineethanol, alpha, alpha-4-pyridylbenzhydrol N-oxide, 2-fluorotriphenylmethanol, triphenylpropargyl alcohol, 4-[(diphenyl)hydroxymethyl]benzonitrile, 1-(2,6-dimethoxyphenyl)-2- methyl-1 -phenyl-1 -propanol, 1,1,2-triphenylpropan-1-ol and p-anisaldehyde carbinol.
Among these alcohols aliphatic alcohols are preferred, more preferred are the alkanols, and especially preferred are methanol, ethanol, n-propanol, iso-propanol, n-butanol, and tert. buta nol.
"x" is the molar ratio of alcohol or water and boron trihalide in the complex BX 3 c x ROH. Ac cording to the present invention "x" is a positive number of more than 0 (zero).
Preferably x may be 0.1 to 10, more preferably 0.2 to 5, even more preferably 0.3 to 3, very preferably 0.5 to 2, and especially 0.7 to 1.3.
Optionally the boron trihalide in the complex may further comprise at least one Bronsted Acid (BA) and/or at least one Lewis Base (LB).
The at least one Bronsted Acid (BA) is preferably selected from the group consisting of organic sulfonic acids and sulfuric acid, preferably sulfonic acids, more preferably aliphatic or aromatic sulfonic acids, even more preferably O to C 4 -alkyl sulfonic acids, especially methane sulfonic acid and ethane sulfonic acid. Examples for the less preferred aromatic sulfonic acids are op tionally substituted C 6 - to Ci 2 -aromatic sulfonic acids, such as benzene sulfonic acid, p-toluene sulfonic acid, and para-C 6 - to C 2 o-alkyl benzene sulfonic acid.
The at least one Lewis Base (LB) comprises at least one oxygen atom with at least one lone electron pair, preferably at least one oxygen atom with at least one lone electron pair, more preferably the Lewis Base is selected from the group consisting of organic compounds with at least one ether or ester function, especially preferably selected from the group consisting of ethers, preferably aliphatic or cycloaliphatic ethers, more preferably selected from the group consisting of di(Ci- to C 4 -alkyl) ethers, tetrahydrofurane, tetrahydropyrane, and dioxane, and especially selected from the group consisting of tetrahydrofurane, tetrahydropyrane, and diox ane.
Using at least one Bronsted Acid (BA) and/or at least one Lewis Base (LB), the complex ac cording to the invention follows the lowing formula BX 3 x x ROH x y BA x z LB wherein number "y" and "z" independently of another may be 0 (zero) or a positive number.
Preferably y may be 0 to 10, more preferably 0.1 to 5, even more preferably 0.15 to 3, very preferably 0.2 to 2, and especially 0.25 to 1.5.
Preferably z may be 0 to 500, more preferably 0 to 450, even more preferably 0 to 400, very preferably 0 to 350, and especially 0 to 300.
It is also possible to use aluminium or iron halides rather than the boron trihalide complex ac cording to the invention.
Examples for aluminium halides are aluminium trihalides, alkylaluminium halides, and dialkylal- uminium halides with aluminium trihalides being preferred.
A suitable aluminium trihalide, hereinafter referred to as AIX 3 , is especially aluminium trifluoride, aluminium trichloride or aluminium tribromide, preferably aluminium trichloride.
A useful alkylaluminium halide is especially a mono(Ci- to C4-alkyl)aluminium dihalide or a di(Cr to C4-alkyl)aluminium monohalide, for example methylaluminium dichloride, ethylalumini- um dichloride, iso-butylaluminium dichloride, dimethylaluminium chloride or diethylaluminium chloride, diiso-butylaluminium chloride, preferably ethylaluminium dichloride, iso-butylaluminium dichloride, diethylaluminium chloride or diiso-butylaluminium chloride and very preferably ethyl- aluminium dichloride and iso-butylaluminium dichloride.
Especially suitable iron trihalides, hereinafter referred to as FeX3, are iron trifluoride, iron trichlo ride or iron tribromide, preferably iron trichloride.
These Lewis Acids other than BX 3 may also be used in a complex as described above, i.e.
AIX 3 x x ROH x y BA x z LB respectively
FeX 3 x x ROH x y BA x z LB wherein
X, x, y, z, ROH, BA, and LB are defined as above. Another object of the present invention is the use of such a complex for copolymerising vinyl ethers (V) and aldehydes (A).
Vinyl ethers (V) for use in the copolymerisation according to the present invention are Ci- to C2o-alkyl vinyl ethers, C3- to C2o-alkenyl vinyl ethers, C5- to Ci2-cycloalkyl vinyl ethers, cyclic vinylethers, such as 2,3-dihydrofuran, 3,4-dihydropyran, vinyl ethers comprising alkylene glycol side chains, vinyl ethers comprising ester groups in the side chain, and C 6 - to Ci2-aryl vinyl ethers, preferably Ci- to C2o-alkyl vinyl ethers, C3- to C2o-alkenyl vinyl ethers, and C5- to C12- cycloalkyl vinyl ethers, more preferably Ci- to C2o-alkyl vinyl ethers and C3- to C2o-alkenyl vinyl ethers, and especially Ci- to C2o-alkyl vinyl ethers.
In one embodiment of the present invention the vinyl ether (V) may bear two or more vinyl ether groups, preferably two to six, more preferably two to four, even more preferably two to three, and especially exactly two.
Preferred vinyl ethers bearing two or more vinyl ether groups are vinyl ethers of polyols, prefer ably diols or polyols with a functionality of three or higher.
Diols used in accordance with the present invention include for example ethylene glycol, pro- pane-1,2-diol, pro-pane-1, 3-diol, butane-1 ,2-diol, butane-1, 3-diol, butane-1, 4-diol, butane-2, 3- diol, pentane-1, 2-diol, pentane-1 , 3-diol, pentane-1, 4-diol, pentane-1, 5-diol, pentane-2, 3-diol, pentane-2, 4-diol, hexane-1, 2-diol, hexane-1, 3-diol, hexane-1, 4-diol, hexane-1, 5-diol, hexane- 1 , 6-diol, hexane-2, 5-diol, hep-tane-1, 2-diol, 1,7-heptanediol, 1,8-octanediol, 1,2-octanediol, 1,9- nonanediol, 1 ,2-decanediol, 1 ,10-decanediol, 1,2-dodecanediol, 1 ,12-dodecanediol, 1,5- hexadiene-3, 4-diol, 1,2- and 1,3-cyclopentanediols, 1,2-, 1,3-and 1 ,4-cyclo-hexanediols, 1,1-, 1 ,2-, 1,3- and 1,4-bis(hydroxymethyl) cyclohexanes, 1,1-, 1,2-, 1,3- and 1,4- bis(hydroxyethyl)cyclohexanes, neopentyl glycol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-2,4- pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2,2,4-trimethyl-1,3- pentanediol, pinacol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycols H0(CH 2 -CH 2 0) n -H or polypropylene glycols H0(CH(CH 3 )-CH-0) n -H, n be ing an integer and being at least 4, polyethylene-polypropylene glycols, the sequence of the ethylene oxide or propylene oxide units being blockwise or random, polytetramethylene glycols, preferably with a molar weight of up to 5000 g/mol, poly-1, 3-propanediols, preferably with a mo lar weight up to 5000 g/mol, polycaprolactones, or mixtures of two or more representatives of the above compounds. Diols whose use is preferred are ethylene glycol, 1,2-propanediol, 1,3- propanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 1,8-octanediol, 1 ,2-, 1 ,3- and 1,4- cyclohexanediol, 1,3- and 1,4-bis(hydroxymethyl)cyclohexane, and diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol.
Alcohols with a functionality of at least three comprise glycerol, trimethylolmethane, trime- thylolethane, trimethylolpropane, 1,2,4-butanetriol, tris(hydroxymethyl) amine, tris(hydroxyethyl)amine, tris(hydroxypropyl)amine, pentaerythritol, diglycerol, triglycerol or high er condensates of glycerol, di(trimethylolpropane), di(pentaerythritol), trishydroxymethyl isocy- anurate, tris(hydroxyethyl) isocyanurate (THEIC), tris(hydroxypropyl) isocyanurate, inositols or sugars, such as glucose, fructose or sucrose, for example, sugar alcohols such as sorbitol, iso- sorbide, mannitol, threitol, erythritol, adonitol (ribitol), arabitol (lyxitol), xylitol, dulcitol (galactitol), maltitol, isomalt, polyetherols with a functionality of three or more, based on alcohols with a functionality of three or more and on ethylene oxide, propylene oxide and/or butylene oxide.
In the case of alcohols with a functionality of hydroxy groups of three or higher not necessary all hydroxy groups may be etherised with vinyl groups as long as the functionality of vinyl groups is at least two. In this case the functionality of vinyl groups may also be a rational number.
Examples for Ci- to C 2 o-alkyl vinyl ethers are methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, /so-propyl vinyl ether, n-butyl vinyl ether, se/c-butyl vinyl ether, /so-butyl vinyl ether, tert- butyl vinyl ether, n- pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-decyl vinyl ether, n-dodecyl vinyl ether, n-tetradecyl vinyl ether, n-hexadecyl vinyl ether, n-octadecyl vinyl ether, and n-eicosyl vinyl ether. Among those examples the Ci- to Cio-alkyl vinyl ethers are preferred and the Ci- to C4-alkyl vinyl ethers very preferred, especially methyl vinyl ether, ethyl vinyl ether, iso-propyl vinyl ether, iso-butyl vinyl ether, and n-butyl vinyl ether.
Examples for C3- to C 2 o-alkenyl vinyl ethers are allyl vinyl ether, tetradec-9-enyl vinyl ether, hex- adec-9-enyl vinyl ether, octadec-9-enyl vinyl ether, octadec-11-enyl vinyl ether, octadec-9,12- dienyl vinyl ether, octadec-9,12,15-trienyl vinyl ether, and eicosa-5,8,11,14-tetraenyl vinyl ether.
Examples for cyclic vinyl ethers are 2,3-dihydrofuran and 3,4-dihydropyran.
Examples for vinyl ethers comprising alkylene glycol side chains are of formula
R 1 -[-Xi-]n-0-HC=CH 2 wherein
R 1 is hydrogen or a linear or branched Ci- to C2o-alkyl, preferably hydrogen or Ci- to C4-alkyl, more preferably hydrogen, methyl, ethyl or n-butyl, and especially hydrogen, n is a positive integer from 1 to 25, preferably from 1 to 20, more preferably from 1 to 15, and most preferably from 1 to 10, and
X is for every i from 1 to n selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, -0-C(CH 3 ) 2 -CH 2 -, -0-CH 2 -CH(C 2 H 5 )-, -0-CH(C 2 H 5 )-CH 2 - und -0-CH(CH 3 )-CH(CH 3 )-, preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, -0-C(CH 3 ) 2 -CH 2 -, -0-CH 2 -CH(C 2 H 5 )-, and -0-CH(C 2 H 5 )-CH 2 -, more preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, and -0-C(CH 3 ) 2 -CH 2 -, most preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )- and -0-CH(CH 3 )-CH 2 -, and especially -0-CH 2 -CH 2 -.
Examples for vinyl ethers comprising ester groups in the side chain of formula
R 2 -(C=0)-[-Xi-]n-0-HC=CH 2 wherein
R 2 is hydrogen or a linear or branched Ci- to C 2 o-alkyl or linear or branched C 2 - to C 2 o-alkenyl, preferably hydrogen or a linear or branched Ci- to Cio-alkyl or linear or branched Ci 2 - to C 2 o- alkenyl, n is a positive integer from 1 to 25, preferably from 1 to 20, more preferably from 1 to 15, and most preferably from 1 to 10, and
Xi is for every i from 1 to n selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, -0-C(CH 3 ) 2 -CH 2 -, -0-CH 2 -CH(C 2 H 5 )-, -0-CH(C 2 H 5 )-CH 2 - und -0-CH(CH 3 )-CH(CH 3 )-, preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, -0-C(CH 3 ) 2 -CH 2 -, -0-CH 2 -CH(C 2 H 5 )-, and -0-CH(C 2 H 5 )-CH 2 -, more preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )-, -0-CH(CH 3 )-CH 2 -, -0-CH 2 -C(CH 3 ) 2 -, and -0-C(CH 3 ) 2 -CH 2 -, most preferably selected from the group consisting of -0-CH 2 -CH 2 -, -0-CH 2 -CH(CH 3 )- and -0-CH(CH 3 )-CH 2 -, and especially -0-CH 2 -CH 2 -.
Examples for C 6 - to Ci 2 -aryl vinyl ethers are phenyl vinyl ether, tolyl vinyl ether, and naphtyl vi nyl ether.
An example for a vinyl ether comprising ester groups in the side chain is vinyloxyethyl malonate (VOEM). Among the above-mentioned vinyl ethers Ci- to C2o-alkyl vinyl ethers and C 3 - to C2o-alkenyl vi nyl ethers are preferred, and more preferably the Ci- to C2o-alkyl vinyl ethers, even more prefer ably Ci- to Cio-alkyl vinyl ethers, very preferably Ci- to C4-alkyl vinyl ethers, and especially me thyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, /so-propyl vinyl ether, /7-butyl vinyl ether, /so-butyl vinyl ether, and tert- butyl vinyl ether.
In one embodiment of the present invention the vinyl ether is a long chain aliphatic vinyl ether selected from the group consisting of C10- to C2o-alkyl vinyl ethers and C10- to C2o-alkenyl vinyl ethers, preferably C10- to C2o-alkyl vinyl ethers.
Preferably in this embodiment the vinyl ether (V) is selected from the group consisting of n-decyl vinyl ether, 3,7-dimethyloct-6-en-1-yl vinyl ether, 3,7-dimethyl-7-octen-1-yl vinyl ether, (E)-3,7- dimethyl-2,6-octadien-1-yl vinyl ether, (Z)-3,7-dimethyl-2,6-octadien-1-yl vinyl ether, n-dodecyl vinyl ether, n-tetradecyl vinyl ether, n-hexadecyl vinyl ether, n-octadecyl vinyl ether, n-eicosyl vinyl ether, tetradec-9-enyl vinyl ether, hexadec-9-enyl vinyl ether, octadec-9-enyl vinyl ether, octadec-11-enyl vinyl ether, octadec-9,12-dienyl vinyl ether, octadec-9,12,15-trienyl vinyl ether, and eicosa-5,8,11,14-tetraenyl vinyl ether.
In another embodiment of the present invention the vinyl ether is a cycloalkyl vinyl ether, prefer ably a C 5 - to Ci2-cycloalkyl vinyl ether, more preferably a C 5 - to C 6 -cycloalkyl vinyl ether.
Examples for C 5 - to Ci2-cycloalkyl vinyl ethers are cyclopentyl vinyl ether, cyclohexyl vinyl ether, cycloheptyl vinyl ether, and cyclododecyl vinyl ether, especially cyclohexyl vinyl ether.
Aldehydes (A) for use in the copolymerisation according to the present invention are selected from the group consisting of optionally substituted Ce- to Ci2-aromatic aldehydes, furfural alde hydes, Ci- to Cioo-aliphatic aldehydes, one- or multifold unsaturated C 3 - to C2o-aliphatic alde hydes, preferably alpha, beta-unsaturated C 3 - to C2o-aliphatic aldehydes, and C 5 - to C 12 - cycloaliphatic aldehydes, preferably selected from the group consisting of optionally substituted Ce- to Ci2-aromatic aldehydes and Ci- to C2o-aliphatic aldehydes.
Ce- to Ci2-aromatic aldehydes are optionally substituted benzaldehyde, 1-naphthaldehyde, and 2-naphthaldehyde.
Preferred is optionally substituted benzaldehyde of formula R 3 -Ph-CHO wherein
Ph is a benzene ring and
R 3 is selected from the group consisting of hydrogen, Ci- to C2o-alkyl, Ci- to C2o-alkyloxy, and R 4 R 5 N-,
R 4 and R 5 independently of another are Ci- to C4-alkyl or together with the nitrogen atom form a five- to seven-membered ring.
Substituent R 3 and the aldehyde group -CHO are preferably located in position 2 or 4 to each other, preferably in position 4.
Examples of R 3 are hydrogen, methyl, ethyl, /7-propyl, /sopropyl, /7-butyl, se r-butyl, /sobutyl, te/t-butyl, /7-pentyl, /7-hexyl, /7-octyl, 2-ethylhexyl, /7-decyl, 2-propylheptyl, /7-dodecyl, n- tetradecyl, /7-hexadecyl, /7-octadecyl, /7-eicosyl, methoxy, ethoxy, tert.-butoxy, 2-ethylhexyloxy, and dimethylamino, preferably hydrogen, methyl, methoxy, and dimethylamino.
Preferred aromatic aldehydes are benzaldehyde, tolualdehyde, vanillin, 7-methoxy benzalde- hyde,
Preferred Ci- to Cioo-aliphatic aldehydes are linear or branched Ci- to Cioo-alkanals or linear or branched C3- to Cioo-alkenals, in which the double bond may be isolated or conjugated with the aldehyde group.
In one embodiment of the present invention the aldehyde is a low molecular, aliphatic, saturated or unsaturated, linear or branched Ci- to Cg-aldehyde, preferably saturated Ci- to Cg-aldehyde, more preferably selected from the group consisting of formaldehyde, acetaldehyde, propio- naldehyde, butyraldehyde, iso valeraldehyde, hexanal and 2-ethylhexyl aldehyde. In one embodiment of the present invention the aldehyde is a medium molecular, aliphatic, sat urated or unsaturated, linear or branched Cio- to C2o-aldehyde, preferably branched unsaturated Cio- to C2o-aldehyde, more preferably selected from the group consisting of undecanal, tride canal, pentadecanal, heptadecanal, and citronellal.
In one embodiment of the present invention the aldehyde is a high molecular, aliphatic, saturat ed or unsaturated, linear or branched C35- to Cioo-aldehyde, preferably C50- to C75-aldehyde.
Such aldehydes are preferably obtainable by Lewis Acid-catalysed polymerisation of a propene,
1 -butene or isobutene to a polyolefin bearing an unsaturated terminal group, followed by hydro- formylation to the corresponding aldehyde.
Hydroformylation is described e.g. in US 6331656 B1, preferably from column 2, line 54 to col umn 5, line 34, very preferably form column 4, line 24 to column 5, line 8, which is incorporated into the present disclosure by reference.
Preferably the aldehyde is selected from the group consisting of aldehydes obtained from hy droformylation or photooxygenation of oligo/polyisobutene with a number average molecular weight of from 100 to 1500, more preferably from 200 to 1200, and very preferably from 250 to 1100.
In one embodiment of the present invention the aldehyde is an alpha, beta-unsaturated C3- to C2o-aliphatic aldehyde, which optionally may be substituted and is linear or branched. Examples are acrolein, methacrolein, crotonaldehyde, 3-hexenal, cis-4-heptenal, 2-ethylhexenal, decenal,
2-propylheptenal, citral, geranial, neral, and cinnamaldehyde.
C5- to Ci2-cycloaliphatic aldehydes may be cyclopentane aldehyde, cyclohexane aldehyde, and cyclododecane aldehyde.
The copolymers according to the invention and obtainable according to the process according to the present invention exhibits a weight average molecular weight M w of from 1000 to 40000, preferably from 5000 to 30000, more preferably from 6000 to 25000 g/mol, determined by gel permeation chromatography.
The process according to the present invention usually yields copolymers with a polydispersity from 1 to 5, preferably from 1.1 to 3, more preferably from 1.2 to 2.5. In the embodiment according to which the vinyl ether (V) bears two or more vinyl ether groups the weight average molecular weight M w may be from 10000 to 150000, preferably from 15000 to 100000, more preferably from 20000 to 90000 g/mol, determined by gel permeation chroma tography.
In the latter embodiment the process according to the present invention usually yields copoly mers with a polydispersity from 1 to 10, preferably from 1.1 to 8, more preferably from 1.2 to 6.
Another subject of the present invention is a process for copolymerisation of at least one vinyl ether (V) and at least one aldehyde (A), optionally in the presence of at least one solvent, char acterised in that the copolymerisation is carried out in the presence of at least one boron trihal ide complex described above, optionally in the presence of at least one Bronsted Acid (BA) and/or Lewis Base (LB).
In the process the at least one vinyl ether (V) and the at least one aldehyde (A) is brought to reaction in a molar ratio of vinyl ethers (V) : aldehydes (A) from 10 : 1.2 to 1 : 1.2, preferably from 7 : 1.2 to 1 : 1.2, more preferably from 5 : 1.2 to 1 : 1.2, even more preferably from 3 : 1.2 to 1 : 1.2, and especially from 2 : 1.2 to 1 : 1.2.
The copolymerisation in the process according to the invention may optionally be conducted in the presence of an inert solvent. The inert solvent used should be suitable for reducing the in crease in the viscosity of the reaction solution which generally occurs during the polymerisation reaction to such an extent that the removal of the heat of reaction which evolves can be en sured. In addition, the selected solvent needs to ensure monomer/polymer solubility even at the low reaction temperature employed. Suitable solvents are those solvents or solvent mixtures which are inert toward the reagents used. Suitable solvents are, for example, aliphatic hydro carbons such as n-butane, n- pentane, n- hexane, n-heptane, n-octane and isooctane, cycloali phatic hydrocarbons such as cyclopentane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and the xylenes, and halogenated hydrocarbons, especially halogenated ali phatic hydrocarbons, such as methyl chloride, dichloromethane and trichloromethane (chloro form), 1,1-dichloroethane, 1,2-dichloroethane, trichloroethane and 1-chlorobutane, and also halogenated aromatic hydrocarbons and alkylaromatics halogenated in the alkyl side chains, such as chlorobenzene, monofluoromethylbenzene, difluoromethylbenzene and trifluoro- methylbenzene, and mixtures of the aforementioned solvents. A non-halogenated solvent is preferred over the list of halogenated solvents. The inventive copolymerisation may be performed in a halogenated hydrocarbon, especially in a halogenated aliphatic hydrocarbon, or in a mixture of halogenated hydrocarbons, especially of halogenated aliphatic hydrocarbons, or in a mixture of at least one halogenated hydrocarbon, especially a halogenated aliphatic hydrocarbon, and at least one aliphatic, cycloaliphatic or ar omatic hydrocarbon as an inert solvent, for example a mixture of dichloromethane and n- hexane, typically in a volume ratio of 10:90 to 90:10, especially of 50:50 to 85:15.
The reaction time of the copolymerisation usually is 0.5 to 24 hours, preferably 1 to 10 hours, and more preferably 1.5 to 7 hours.
The copolymerisation is usually carried out at a temperature of from -90 to 0 °C, preferably from -80 to -20 °C, more preferably from -78 to -34 °C.
The tuning of reaction time and temperature depends on the reactivity of aldehyde (A), vinyl ether (V), and boron trihalide complex used. It may be necessary to systematically vary reaction time, temperature, and boron trihalide complex in order to optimise yield and selectivity of the copolymerisation.
Next to the polymer, also a certain amount of trimer/oligomers is being formed. Aoshima has also reported these side products with GaC , while similar amounts of trimer/oligomers were found with BF 3 .
After the reaction has reached the desired conversion, the copolymerisation is stopped by quenching with at least one of alcohols, water, ammonia, amines, hydroxides, carbonates, and hydrogen carbonates. Ammonia, amines, hydroxides, carbonates, and hydrogen carbonates may also be used as aqueous solutions.
Alcohols may for example be the above-mentioned alcohols ROH, preferably ethanol.
Water and alcohols are preferred among the mentioned quenching agents.
The quenching agent is used at least in amounts sufficient to deactivate the boron trihalide complex.
Especially in the case of water or aqueous solutions as quenching agent the aqueous phase furthermore acts to extract hydrolysed products of the boron trihalide complex from the reaction mixture or water-soluble by-products. Quenching usually occurs at the reaction temperature at which the copolymerisation is conduct ed and usually only takes a few seconds to several minutes to happen. After quenching is com pleted the reaction mixture is allowed to warm up to the desired temperature at which the reac tion mixture shall further be processed, preferably to room temperature.
Optionally, the copolymers can be purified using an extraction procedure which removes resid ual monomer and/or salts.
In a preferred embodiment a further processing of the reaction mixture comprises the hydrolysis of the copolymer obtained according to the reaction according to the invention.
For the hydrolysis the copolymer is optionally dissolved in at least one solvent and reacted with water in the presence of at least one Bronsted Acid with a pK a -value of not more than 3.0, more preferably not more than 2.0.
The solvent in the hydrolysis step may be the same of different from the solvent in which the copolymerisation is carried out.
Preferably an inert organic solvent is used which is water soluble so that the reaction mixture is well mixed with the Bronsted Acid used which usually is an aqueous solution. Examples for such solvents are ethers, especially tetrahydrofurane and dioxane.
Examples of Bronsted Acids are hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, methane sulfonic acid, ethane sulfonic acid, benzene sulfonic acid, p-toluene sulfonic acid, and para- Ce- to C2o-alkyl benzene sulfonic acid, preferably in their aqueous solutions. Very prefera bly hydrochloric acid, phosphoric acid, and sulfuric acid are used, especially hydrochloric acid and phosphoric acid.
The reaction mixture to which the Bronsted Acid is added is stirred for a time of from 0.5 to 96 hours, preferably from 1 to 48 hours at a hydrolysis temperature of from 0 °C to 60 °C, prefera bly from ambient temperature to 40 °C.
After the hydrolysis is completed the reaction mixture is neutralised, preferably with aqueous solutions of (earth) alkaline metal hydroxides, -carbonates, or -hydrogen carbonates.
Further water immiscible organic solvent may be added and the organic phase is washed one or several times with water or brine. Afterwards the organic phase may be used as such or the solvent or solvents used may be dis tilled off at reduced temperature.
The product of the hydrolysis is an alpha, beta-unsatu rated aldehyde based upon aldehyde (A) which is extended by two further carbon atoms now forming Ci and C 2 of the newly formed al pha, beta-unsaturated aldehyde. The CHO-group of aldehyde (A) now forms C 3 of the newly formed alpha, beta-unsaturated aldehyde.
Hence, for example benzaldehyde may be converted into cinnamyl aldehyde using the copoly merisation according to the present invention followed by hydrolysis of the resulting copolymer.
Furthermore, if aldehydes from natural sources are used as comonomers, such as benzalde hyde, citronellal or citral, the resulting copolymer can be produced using sustainable resources.
With the appropriate choice of aldehyde and vinyl ether only environmentally friendly degrada tion products are released.
The examples which follow are intended to illustrate the present invention in detail without re stricting it.
Examples
Preparation of BF 3» MeOH
10 g of dry methanol were placed in a stirred vessel and purged with gaseous BF 3 under inert conditions at -20 °C. The determination of BF 3 to methanol ratio was performed via elemental analysis.
Typical polymerisation procedure
Reagents were not distilled or dried before use, but used as obtained. Polymerisation was car ried out under a dry nitrogen atmosphere in a 500 ml_ baked glass tube equipped with a four way stopcock. The pre-chilled Bronsted acid was added to a stirred pre-chilled mixture of the monomers, the Lewis Base (optional) and 200 mL toluene at 0 °C. The temperature was subse quently lowered to -78°C and the reaction was started by the addition via dry medical syringe of pre-chilled Lewis acid. The reaction mixture was magnetically stirred throughout the polymeriza- tion. After a reaction time of 2-6 hours, the polymerization was quenched with pre-chilled meth anol containing a small amount of ammonia solution. The quenched reaction mixture was dilut ed with dichloromethane and then washed with water to remove the initiator residues. After fil tration, the solvent and other volatiles were evaporated under reduced pressure (50 °C, 5 mbar), and the residue was vacuum-dried for at least 6 h at 50 °C. The monomer conversion was determined by 1 H NMR, molecular weight and molecular weight distribution by GPC in THF against polystyrene standards.
Typical extraction procedure (optional) The obtained copolymer was washed two times with methanol. Each time, the upper methanol phase was discarded. The obtained viscous or solid residue was subsequently dried under re duced pressure (50 °C, 5 mbar). The copolymer was dissolved in few dichloromethane and placed on a foil. Solvent was allowed to evaporate and the obtained film was dried at 50 °C, 10 mbar overnight. In some cases, a white powder was obtained by milling of the film in a milling apparatus.
Typical hydrolysis procedure
The copolymer was dissolved in few THF under magnetic stirring. A 1.0 M acid solution was added and the mixture was stirred for 4 days at room temperature. Then, aqueous NaOH was added. The mixture was diluted with dichloromethane and the two phases were separated by extraction. The organic phase was washed three times with water after which the solvents were evaporated at 25-50 °C, 5 mbar to (typically) obtain a transparent, oily or solid product.
Table 1 : Overview of examples.
VE: vinyl ether
IBVE: /so-butyl vinyl ether
EVE: ethyl vinyl ether
TEG-DVE = triethylene glycol divinyl ether
MeOH: methanol
EtSChH / MeSChH: ethane / methane sulfonic acid n.d. = not determined
Mw measured using UV-detection of crude polymer unless explicitly stated to be determined using Rl-detection
(C): Comparative Example
Residual aldehyde: as determined in the crude polymer by 1 H-NMR spectroscopy. After extrac tion, the residual aldehyde levels after typically <1%.
A comparison of comparative Example 1 with Examples 4 to 6 shows comparable conversion rates and molecular weight as with GaC , however, with the much easier to handle catalyst complex BF 3» (0.92MeOH) according to the present invention.
The catalyst system BF3»(OEt)2 does not yield any significant amounts of a copolymer of anisaldehyde and /so-butyl vinyl ether.
A comparison of Example 4 with Examples 15 and 16 shows an increase in the glass tempera ture of the polymer as measured by differential scanning calorimetry (DSC). This can be ex plained by the higher molecular weight / crosslinking of Example 15 and 16 versus Example 4.
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