Liquid 1,3-dioxolane copolymer

Abstract

The invention provides 1,3-dioxolane copolymers of the general formula I: H-[O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2 [O-CH2-O-CHR 1 -CHR 2 -] y1 [O-CHR 1 -CHR 2 O-CH2-] y2 OH (I), wherein x1+x2 has a value of 10 to 2000, R 1 and R 2 are hydrogen radicals or C1 to C 18 alkyl, wherein in each case at least one of the radicals R 1 or R 2 in the units [O-CH2-O-CHR y1 -CHR 1 -] 2 and [O-CHR y2 -CHR 1 O-CH2-] 2 is C1 to C 18 alkyl, with the proviso that y1+y2 has a value of 3 * (x1+x2+y1+y2) / 100 to 50 * (x1+x2+y1+y2) / 100; and a process for its preparation.

Description

[0001] This invention relates to 1,3-dioxolane, copolymers of 1,3-dioxolane, and alkyl-substituted 1,3-dioxolane, and methods for their preparation.

[0002] The enormous contribution of increased CO2 emissions to climate change is undeniable, and not only since the signing of the Paris Climate Agreement, but reducing CO2 emissions has become a crucial factor in preventing global average temperature rise.

[0003] The production of plastics also releases a significant amount of CO2 into the atmosphere; according to EIT Climate-KIC projections, by 2050, plastics production alone will account for 15-20% of global CO2 emissions. One way to overcome this trend is to utilize CO2 in plastics production and integrate it into the value chain as a raw material, rather than as waste.

[0004] In this paper, polyacetals represent an attractive class of plastics that can be produced via cyclic acetal intermediates, particularly by catalytic fixation of CO2 using green hydrogen.

[0005] However, conventional polyacetals (also known as polyoxymethylene (POM), such as those obtained by polymerization of formaldehyde or trioxane (POM-H) or by ring-opening polymerization of 1,3-dioxolane (POM-C)) are solid at room temperature because the polymer has crystalline sub-parts and associated melting points that, depending on the application, hinder further processing or functionalization.

[0006] Therefore, the object of the present invention is to obtain a polyacetal that is liquid over a wide temperature range and can be produced from cyclic acetals.

[0007] The intention of the controlled introduction of incompleteness in the form of alkyl groups extending from the polymer backbone is to eliminate, rather than simply reduce, the crystallinity of the polyacetal. This amorphous behavior can be detected by differential scanning calorimetry if only the glass transition point is present and not the melting point.

[0008] US7030207 BB describes a polyacetal formed from trioxane and 1,3-dioxolane, whose crystallization temperature can be lowered, but the polymer crystallizes below a certain temperature.

[0009] The publication "Thermal stability and dynamic mechanical properties of acetal copolymers" Angew. Makromol. Chem. 1999, 265, 55-61 describes the copolymerization of trioxane with alkylated 1,3-dioxolane, but no liquid product was obtained.

[0010] Masahiko Okada et al., “Polymerizability of Methyl Substituted 1,3-Dioxolanes”, Makromolekulare Chemie 176, 859-872 (1975), describes the homopolymerization of 4-methyl-1,3-dioxolanes to form a viscous polymer, in which the monomer and polymer exist in equilibrium. The polymerization requires low temperatures and a very long reaction time of several days.

[0011] EP3020741A describes the possibility of preparing copolymers from 1,3-dioxolane and other monomers. The properties of the copolymers are not described.

[0012] This invention provides a 1,3-dioxolane copolymer of general formula I.

[0013] H-[O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2

[0014] [O-CH2-O-CHR 1 -CHR 2 -] y1 [O-CHR 1 -CHR 2 O-CH2-] y2 OH(I),

[0015] in

[0016] x1+x2 has values ​​ranging from 10 to 2000.

[0017] R 1 and R 2 It is a hydrogen group or C1 to C 18 Alkyl, wherein in each case the unit [O-CH2-O-CHR] 1 -CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 At least one group R in 1Or R 2 It is C1 to C 18 alkyl,

[0018] The condition is that y1+y2 has 3 * (x1+x2+y1+y2) / 100 to 50 * The value of (x1+x2+y1+y2) / 100.

[0019] The copolymers are formed from 1,3-dioxolane rings and 1,3-dioxolane rings substituted at the 4- and / or 5-positions. They are liquid over a wide temperature range, making them highly suitable for further processing.

[0020] They preferably have a glass transition temperature of -50°C to -70°C, and particularly preferably no melting point. The copolymers begin to decompose at >110°C, especially at >100°C.

[0021] 1,3-Dioxolane copolymers contain random or block units [O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2 [O-CH2-O-CHR] 1 -CHR 2 -] y1 [O-CHR] 1 -CHR 2 O-CH2-] y2 .

[0022] Preferably, x1+x2 has a value of 20 to 1000, particularly preferably 30 to 500, and especially 50 to 300.

[0023] Alkyl R 1 and R 2 Examples are straight-chain and branched alkyl groups, such as methyl, ethyl, isooctyl, and n-octyl, as well as cycloalkyl groups such as cyclohexyl. Preferably, R 1 and R 2 It is a hydrogen group or a C1 to C6 alkyl group, with a particular preference for a hydrogen group or methyl, ethyl, n-propyl or isopropyl.

[0024] Preferably, in each case, in unit O-CH2-O-CHR 1 -CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 Only one group R in 1 Or R 2 It is C1 to C 18 alkyl.

[0025] Preferably, y1+y2 has 5 * (x1+x2+y1+y2) / 100 to 40 * The value of (x1+x2+y1+y2) / 100 is preferably 10. * (x1+x2+y1+y2) / 100 to 30 * The value of (x1+x2+y1+y2) / 100, especially 14. * (x1+x2+y1+y2) / 100 to 25 * The value of (x1+x2+y1+y2) / 100.

[0026] The 1,3-dioxolane copolymer preferably has a molecular weight Mw between 750 and 300,000, particularly preferably between 1,500 and 125,000, very particularly preferably between 2,200 and 63,000, and especially preferably between 4,000 and 25,000.

[0027] The 1,3-dioxolane copolymer preferably has a dynamic viscosity at 25°C between 50 mPas and 500 Pas, particularly between 500 mPas and 200 Pas, and especially between 1 Pas and 100 Pas.

[0028] The 1,3-dioxolane copolymer of general formula I above can be prepared in a simple manner and with a short reaction time.

[0029] The present invention also provides a method for preparing 1,3-dioxolane copolymers of general formula I above.

[0030] H-[O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2

[0031] [O-CH2-O-CHR 1 -CHR 2 -] y1 [O-CHR 1 -CHR 2 O-CH2-] y2 OH(I),

[0032] in

[0033] x1+x2 has values ​​ranging from 10 to 2000.

[0034] R 1 and R 2 It is a hydrogen group or C1 to C 18 Alkyl, wherein in each case the unit [O-CH2-O-CHR] 1-CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 At least one group R in 1 Or R 2 It is C1 to C 18 alkyl,

[0035] The condition is that y1+y2 has values ​​ranging from 3*(x1+x2+y1+y2) / 100 to 50*(x1+x2+y1+y2) / 100.

[0036] In this method, 1,3-dioxolane is copolymerized with alkyl-substituted 1,3-dioxolane of general formula II in the presence of Lewis or Brønsted acids.

[0037]

[0038] In general formula II, an alkyl group R is present at the 4- and 5-positions of the 1,3-dioxolane ring. 1 and R 2 .

[0039] This method involves the ring-opening polymerization of dioxolane monomers catalyzed by cation induction. The catalyst is a Lewis acid or a Brønsted acid.

[0040] In this method, based on the total amount of 1,3-dioxolane and alkyl-substituted 1,3-dioxolane of general formula II, it is preferred to use at least 10 mol%, particularly preferably at least 20 mol%, especially at least 30 mol% of alkyl-substituted 1,3-dioxolane of general formula II.

[0041] Since the alkyl-substituted 1,3-dioxolane of general formula II is less reactive than 1,3-dioxolane, more alkyl-substituted 1,3-dioxolane than arithmetically required is needed in this method to obtain a certain proportion of y1+y2.

[0042] Examples of acids are Lewis acids, such as BF3, AlCl3, TiCl3, SnCl4, SO3, PCl5, POCl3, FeCl3 and their hydrates and ZnCl2; Brønsted acids, such as boric acid, tetrafluoroboric acid, nitric acid, nitrous acid, phosphoric acid, phosphorous acid, hypophosphoric acid, sulfuric acid, sulfurous acid, peroxysulfuric acid, hydrochloric acid, hydroiodic acid, hydrobromic acid, perchloric acid, hexafluorophosphoric acid, aluminum chloride, zinc chloride, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid; and carboxylic acids, such as chloroacetic acid, trichloroacetic acid, acetic acid, acrylic acid, benzoic acid, trifluoroacetic acid, citric acid, crotonic acid, formic acid, fumaric acid, maleic acid, malonic acid, gallic acid, itaconic acid, lactic acid, tartaric acid, oxalic acid, phthalic acid, and succinic acid; acidic ion exchangers, acidic zeolites, acid-activated bleaching clay, and acid-activated carbon black.

[0043] Boron trifluoride ether and trifluoromethanesulfonic acid are particularly preferred.

[0044] An initiator can be used in this method. The initiator used is preferably a monofunctional or difunctional alcohol, and ethylene glycol is particularly preferred.

[0045] This method can be carried out with or without an aprotic solvent. If an aprotic solvent is used, a solvent or solvent mixture having a boiling point or boiling range of up to 120°C at 0.1 MPa is preferred. Examples of such solvents are ethers, such as dioxane, tetrahydrofuran, diethyl ether, methyl tert-butyl ether, diisopropyl ether, and diethylene glycol dimethyl ether; chlorinated hydrocarbons, such as dichloromethane, chloroform, tetrachloromethane, 1,2-dichloroethane, and trichloroethylene; hydrocarbons, such as pentane, n-hexane, mixtures of hexane isomers, heptane, octane, gasoline, petroleum ether, benzene, toluene, and xylene; and siloxanes, particularly linear dimethyl polysiloxanes with trimethylsilyl end groups having 0 to 6 dimethylsiloxane units, or cyclic dimethyl polysiloxanes having preferably 4 to 7 dimethylsiloxane units, such as hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentansiloxane.

[0046] Ketones, such as acetone, methyl ethyl ketone, diisopropyl ketone, methyl isobutyl ketone (MIBK); esters, such as ethyl acetate, butyl acetate, propyl propionate, ethyl butyrate, ethyl isobutyrate; carbon disulfide and nitrobenzene, or mixtures of these solvents.

[0047] The term "solvent" does not imply that all reactants must be dissolved in it. Reactions can also take place in suspensions or emulsions of one or more reactants. Reactions can also take place in solvent mixtures with miscibility gaps, in which case at least one reactant is soluble in each mixed phase.

[0048] Particularly preferably, a solution of trifluoromethanesulfonic acid and an initiator is used, wherein dichloromethane is used as the preferred solvent.

[0049] The amount of catalyst and initiator used determines the achievable molecular weight of the 1,3-dioxolane copolymer of general formula I.

[0050] The method is preferably carried out at a temperature between 10°C and 60°C, particularly between 15°C and 40°C, and especially between 21°C and 30°C. A reaction temperature of 23°C is particularly preferred.

[0051] The reaction is preferably post-treated by deactivating the catalyst with the aid of a suitable base, washing with a hydrocarbon such as heptane, and drying under reduced pressure.

[0052] Suitable bases are preferably pyridine, triethylamine, or aqueous sodium hydroxide solution.

[0053] In the following embodiments, unless otherwise stated in each case, all figures for quantity and percentage are based on weight, all pressures are 0.10 MPa (absolute), and all temperatures are 20°C. Example

[0054] Analysis of the entire invention:

[0055] NMR spectroscopy determination of alkyl ethylene oxide bridges y1+y2 Ratio:

[0056] In Bruker Avance 500 or Ascend 500 (500MHz), 1 Measurements were performed in CDCl3 solution using an H-spectrum. All measurements were taken against a TMS external standard. The relative proportions of monomer units in the polymer were determined by integrating the signals from each set.

[0057] SEC (size exclusion chromatography) was used to determine the number-average and quality-average molecular weights Mn and Mw, as well as polydispersity.

[0058] The measurement was performed relative to a polystyrene standard in THF at 35°C and a flow rate of 0.3 ml / min, using a RID (refractive index detector) on an Agilent PLgel MiniMIX-C Guard column with an injection volume of 20 μl.

[0059] Rheometer for measuring dynamic viscosity:

[0060] The measurements were performed at 25°C on an Anton Paar MCR 320 rotational viscometer. A graphical evaluation was performed by plotting viscosity against shear stress.

[0061] DSC (Differential Scanning Calorimetry / Differential Thermal Analysis) for determining melting point and glass transition temperature:

[0062] The measurements were performed on a Mettler Toledo DSC-1 apparatus in two runs at a heating or cooling rate of 10 K / min over a temperature range of -150 °C to 150 °C. The second run was used to determine the melting point and glass transition temperature.

[0063] TGA analysis determines the start of the decomposition:

[0064] The onset of decomposition was determined on a Mettler Toledo TGA-2 apparatus, with the sample heated in an oxygen atmosphere at a heating rate of 10 K / min.

[0065] Example 1, not the present invention:

[0066] 8.0 mL (114 mmol) of 1,3-dioxolane (DXL) was placed in a flask, and 14 μL of boron trifluoride ether was added while stirring. An increase in viscosity was observed; after 10 minutes, the reaction solution was a solid. 5 mL of 5% sodium carbonate solution was added. The mixture was dissolved in dichloromethane, and the product was precipitated in heptane and filtered. The solid was dried under reduced pressure to a white solid.

[0067] Example 2:

[0068] 3.6 mL (50 mmol) of 1,3-dioxolane (DXL) and 5.1 g (50 mmol) of 4-ethyl-1,3-dioxolane (EDX) were placed in a flask, and 14 μL of boron trifluoride ether was added while stirring. An increase in viscosity was observed. After 4 hours, 5 mL of 5% sodium carbonate solution was added and the product was washed with heptane. The viscous residue was dried under reduced pressure.

[0069] Example 3:

[0070] 5.2 mL (75 mmol) of 1,3-dioxolane (DXL) and 2.55 g (25 mmol) of 4-ethyl-1,3-dioxolane (EDX) were placed in a flask, and 14 μL of boron trifluoride ether was added while stirring. An increase in viscosity was observed. After 2 hours, stirring of the reaction mixture was no longer possible. 5 mL of 5% sodium carbonate solution and dichloromethane were added, and the product was precipitated in heptane. The highly viscous white residue was dried under reduced pressure.

[0071] Example 4:

[0072] 5.8 mL (83 mmol) of 1,3-dioxolane (DXL) and 1.74 g (17 mmol) of 4-ethyl-1,3-dioxolane (EDX) were placed in a flask, and 14 μL of boron trifluoride ether was added while stirring. The reaction was highly exothermic, and an increase in viscosity was observed. After 5 minutes, stirring of the reaction mixture was no longer possible. 5 mL of 5% sodium carbonate solution and 5 mL of dichloromethane were added, and the product was precipitated in heptane. The product was dried under reduced pressure to obtain a white solid.

[0073] Example 5:

[0074] 5.1 g (50 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 14 μl of boron trifluoride ether were placed in a flask. 3.6 mL (50 mmol) of 1,3-dioxolane (DXL) was added dropwise over 15 minutes with stirring. The reaction mixture was terminated after 2 hours by adding 5 mL of 5% sodium carbonate solution. After the addition of dichloromethane, the product was washed with heptane and dried under reduced pressure. The result was a viscous oil.

[0075] Example 6:

[0076] 2.55 g (25 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 14 μl of boron trifluoride ether were placed in a flask. 4.2 mL (60 mmol) of 1,3-dioxolane (DXL) was added dropwise over 30 minutes with stirring. The reaction mixture was terminated after 2 hours by adding 5 mL of 5% sodium carbonate solution. After the addition of dichloromethane, the product was added dropwise to heptane, the heptane phase was removed, and the residue was dried under reduced pressure. The result was a viscous oil.

[0077] For Examples 7 to 10:

[0078] Preparation of catalyst solution:

[0079] Combine 10 ml of anhydrous dichloromethane, 1000 μl of ethylene glycol, and 76 μl of trifluoromethanesulfonic acid, and stir at room temperature for 1 hour.

[0080] Example 7:

[0081] 4.5 ml of the catalyst solution and 4.5 ml of anhydrous dichloromethane were placed in a flask and the temperature was adjusted to 23 °C. Then, 67.5 g (640 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 45 ml (640 mmol) of 1,3-dioxolane (DXL) were added and stirred. The reaction mixture turned pink.

[0082] After 4.5 hours, pyridine was added until the mixture lost its color. The product was washed with heptane and then dried under reduced pressure.

[0083] Example 8:

[0084] A 9.0 mL catalyst solution was placed in a flask and the temperature was adjusted to 23 °C. Then, 67.5 g (640 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 45 mL (640 mmol) of 1,3-dioxolane (DXL) were added, and the reaction mixture was stirred at 21 °C for 60 minutes. The reaction mixture turned pink. After 5.5 hours, pyridine was added until the mixture lost its color. The product was washed with heptane and then dried under reduced pressure.

[0085] Example 9:

[0086] Place 0.25 mL of catalyst solution and 0.25 mL of dichloromethane in a flask. Then add 3.75 g (35 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 2.5 mL (35 mmol) of 1,3-dioxolane (DXL), and stir the mixture at 23 °C for 3 hours. Add 10 mL of dichloromethane to the reaction mixture, and then add 10% sodium hydroxide solution dropwise until the pH reaches 7. Wash the product twice with 20 mL of water and dry under reduced pressure.

[0087] Example 10:

[0088] 0.25 mL of catalyst solution and 0.25 mL of dichloromethane were placed in a flask. Then, 800 mg (8 mmol) of 4-ethyl-1,3-dioxolane (EDX) and 4.7 mL (67 mmol) of 1,3-dioxolane (DXL) were added, and the mixture was stirred at 23 °C. After 4 hours, 1 mL of pyridine and 5 mL of dichloromethane were added. After adding heptane, the supernatant was decanted, and the product was dried under reduced pressure. The result was a white solid.

[0089]

Claims

1. 1,3-Dioxolane copolymer of general formula I: H- [O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2 [O-CH2-O-CHR 1 -CHR 2 -] y1 [O-CHR 1 -CHR 2 O-CH2-] y2 OH (I), in x1+x2 has values ​​ranging from 10 to 2000. R 1 and R 2 It is a hydrogen group or C1 to C 18 Alkyl, wherein in each case the unit [O-CH2-O-CHR] 1 -CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 At least one group R in 1 Or R 2 It is C1 to C 18 alkyl, The condition is that y1+y2 has to The value of .

2. The 1,3-dioxolane copolymer according to claim 1, wherein the group R 1 and R 2 Selected from hydrogen groups or methyl, ethyl, n-propyl or isopropyl.

3. The 1,3-dioxolane copolymer according to claim 1 or 2, wherein in each case the unit [O-CH2-O-CHR] 1 -CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 There is only one group R in it. 1 Or R 2 It is C1 to C 18 alkyl.

4. The 1,3-dioxolane copolymer according to claim 1 or 2, having a molecular weight Mw between 750 and 300,000, said molecular weight Mw being measured as follows: relative to a polystyrene standard, in THF, at 35°C, at a flow rate of 0.3 ml / min, and detected by RID (refractive index detector) on an Agilent PLgel MiniMIX-C Guard column with an injection volume of 20 μl.

5. The 1,3-dioxolane copolymer according to claim 1 or 2, having a dynamic viscosity at 25°C between 50 mPa·s and 500 Pa·s, said dynamic viscosity being measured at 25°C on an Anton Paar MCR 320 rotational viscometer, wherein the viscosity is plotted against shear stress for graphical evaluation.

6. A method for preparing 1,3-dioxolane copolymers of general formula I, H- [O-CH2-O-CH2-CH2-] x1 [O-CH2-CH2O-CH2-] x2 [O-CH2-O-CHR 1 -CHR 2 -] y1 [O-CHR 1 -CHR 2 O-CH2-] y2 OH (I), in x1+x2 has values ​​ranging from 10 to 2000. R 1 and R 2 It is a hydrogen group or C1 to C 18 Alkyl, wherein in each case the unit [O-CH2-O-CHR] 1 -CHR 2 -] y1 and [O-CHR] 1 -CHR 2 O-CH2-] y2 At least one group R in 1 Or R 2 It is C1 to C 18 alkyl, The condition is that y1+y2 has 3 (x1+x2+y1+y2) / 100 to 50 The value of (x1+x2+y1+y2) / 100, In this method, 1,3-dioxolane is copolymerized with alkyl-substituted 1,3-dioxolane of general formula II in the presence of Lewis or Brønsted acids. (II)。 7. The method according to claim 6, wherein the acid is selected from boron trifluoride ether and trifluoromethanesulfonic acid.

8. The method according to claim 6 or 7, wherein the temperature is between 10°C and 60°C.

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