3-GLYCIDYLOXYPROPYLTRIALKOXYSILANES HAVING LONG-CHAIN ALKOXY GROUPS, PROCESSES FOR PRODUCTION AND USE

Abstract

A novel compound, which is 3-glycidyloxypropyltri(-2-propylheptoxy)silane. A process for producing a 3-glycidyloxypropyltrialkoxysilane having long-chain alkoxy groups of formula (I)

##STR00001## or of formula (II)

##STR00002##

where m=1 or 2, n=0 or 1, p=3, 4, 5, 6, 7, 8, 9 or 10, where the method includes heating 3-glycidyloxypropyltrimethoxysilane or 3-glycidyloxypropyltriethoxysilane, with a stoichiometric amount or an excess of a longer-chain alcohol from the group of the C5- to C16-alcohols, in the presence of titanium tetrabutoxide as catalyst, with stirring to a temperature of not more than 225 C., reacting, and then following the reaction by removing methanol/ethanol and excess reactant alcohol from the product mixture by distillation, optionally under reduced pressure. A method of using the 3-glycidyloxypropyltri(-2-propylheptoxy)silane for functionalization of rubber and using the rubber in treads for reducing rolling resistance in tires.

Claims

1. A compound, wherein the compound is 3-glycidyloxypropyltri(-2-propylheptoxy)silane.

2. A process for producing a 3-glycidyloxypropyltrialkoxysilane having long-chain alkoxy groups of formula (I): ##STR00005## or of formula (II) ##STR00006## wherein m=1 or 2, n=0 or 1, p=3, 4, 5, 6, 7, 8, 9 or 10, the process comprising: heating 3-glycidyloxypropyltrimethoxysilane or 3-glycidyloxypropyltriethoxysilane, with a stoichiometric amount or an excess of a longer-chain alcohol from the group of the C5- to C16-alcohols, in the presence of titanium tetrabutoxide as catalyst, with stirring to a temperature of not more than 225 C., reacting to obtain a product mixture, and after the reacting, removing methanol/ethanol and excess reactant alcohol from the product mixture by distillation, to obtain a product.

3. The process according to claim 2, wherein the long-chain alcohol employed is 2-ethylhexan-1-ol, isononan-1-ol or 2-propylheptan-1-ol.

4. The process according to claim 2, wherein glycidyloxypropyltrimethoxysilane or glycidyloxypropyltriethoxysilane and a long-chain alcohol, are employed in a molar ratio of 1:3 to 6.

5. The process according to claim 2, wherein 0.01% to 0.5% by weight of titanium tetrabutoxide based on the employed amount of 3-glycidyloxypropyltrimethoxysilane is employed.

6. The process according to claim 2, wherein the reaction is performed at a temperature of 100 to 220 C.

7. The process according to claim 2, wherein the reaction is performed over a period of 6 to 24 hours.

8. The process according to claim 2, wherein the transesterification is performed with a yield of 90%.

9. The process according to claim 2, wherein a product is obtained as a composition having a content of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane/3-glycidyloxypropyltri(-2-propylheptoxy)silane of 90% by weight, wherein the components in the composition sum to 100% by weight.

10. A composition, comprising a content of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane of 90% by weight obtained by the process according to claim 2, wherein the components in the composition sum to 100% by weight.

11. The composition according to claim 10, comprising a content of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane of 95%.

12. The composition according to claim 10, comprising a content of alcohols of methanol or ethanol of 1% by weight, based on the composition.

13. The composition according to claim 10, having a content of mixed esters 10% by weight, wherein the mixed esters are selected from the group consisting of 3-glycidyloxypropyldi(-2-ethylhexoxy)monomethoxysilane, 3-glycidyloxypropyldi(-2-ethylhexoxy)monoethoxysilane, 3-glycidyloxypropylmono(-2-ethylhexoxy)dimethoxysilane and 3-glycidyloxypropylmono(-2-ethylhexoxy)diethoxysilane.

14. A method of functionalizing rubber, comprising anionically polymerizing the rubber in the presence of the composition according to claim 10, wherein the 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane is employed for chain termination.

15. A method, comprising modifying rubber with at least one 3-glycidyloxypropyltrialkoxysilane having long-chain alkoxy groups obtained by the process according to claim 2.

16. A rubber mixture, comprising a rubber modified with at least one 3-glycidyloxypropyltrialkyloxysilane having long-chain alkoxy groups obtained by the process according to claim 2.

17. The method according to claim 14, comprising applying a rubber mixture comprising a solution styrene-butadiene rubber (S-SBR) or butadiene rubber (BR) modified with the composition in treads of at least one tire.

18. The process according to claim 2, wherein the 3-glycidyloxypropyltrialkyloxysilane having long-chain alkoxy groups is 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane.

19. The process according to claim 4, wherein the long-chain alcohol is 2-ethylhexanol or 2-propylheptanol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0034] The process according to the invention is generally performed as follows:

[0035] Generally a mixture of for example 3-gycidyloxypropyltrimethoxysilane and a stoichiometric amount to relative excess by molecular weight of 2-ethylhexanol or 2-propylheptanol and also a catalytic amount of titanium tetrabutoxide are initially charged into a suitable reaction apparatusfor example based on a reaction vessel having feeds for reactant metering, stirrer, heating means, temperature control/regulation, reflux condenser and bridge with receiver, the mixture is heated with stirring preferably to a temperature of 100 to 220 C., in particular to a temperature in the range from 120 to 140 C., the mixture is reacted at this temperature for a sufficiently long period, preferably over 6 to 24 hours, and then following the reaction phase the volatile components still present in the reaction mixture/product mixture thus obtained, such as methanol/ethanol, and any excess long-chain alcohol, such as 2-ethylhexanol/2-propylheptanol, are suitably distilled off under reduced pressure to work up the reaction mixture/product mixture by means of distillation and hence obtain the product/product mixture. For example, to perform the distillation, the reaction mixture/product mixture present after reaction may be transferred from the reaction vessel into a separate distillation unit and worked up by fractional distillation. It is also possible to apply a vacuum during distillation, i.e. to distil under reduced pressure, and facultatively also to pass nitrogen through the product/product mixture present in the bottom of the distillation apparatus. The product/the composition according to the invention is thus advantageously obtained as a colourless to yellowish, slightly viscous liquid in the bottom of the distillation apparatus used. Alternatively, the volatile alcohols, such as methanol/ethanol and the excess long-chain alcohols, may be gently removed under vacuum using a thin-film evaporator from the product/product mixture which is advantageously collected as so-called high boiler.

[0036] Surprisingly, performing the process according to the invention achieves in particularly advantageous fashion virtually complete transesterification with a yield of 90%, in particular 95%, and thus makes it possible, to great advantage, to provide a corresponding novel reaction product. It is thus possible by the process according to the invention advantageously to obtain novel 3-glycidyloxypropyltrialkoxysilanes having long-chain alkoxy groups according to formula (I) and formula (II) and corresponding compositions having a high content of corresponding 3-glycidyloxypropyltrialkoxysilanes having long-chain alkoxy groups, in particular of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane and 3-glycidyloxypropyltri(-2-propylheptoxy)silane, of 90% by weight, preferably 95% by weight.

[0037] The present invention therefore also provides compositions having a content of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane/3-glycidyloxypropyltri(-2-propylheptoxy)silane of 90% by weight, preferably 95% by weight, which are obtainable by the process according to the invention, wherein the components in the composition sum to 100% by weight.

[0038] The invention further provides a composition/a composition produced according to the invention having a content of 3-glycidyloxypropyltri(-2-ethylhexoxy)silane/3-glycidyloxypropyltri(-2-propylheptoxy)silane of 90% by weight, preferably 95% by weight, based on the composition.

[0039] A composition according to the invention/a composition produced according to the invention preferably furthermore has a content of methanol/ethanol of 1% by weight, preferably from 0.5% by weight down to the detection limit, based on the composition, and thus also features, also from an environmental standpoint only, a very low proportion of VOCs (volatile organic compounds). Compositions according to the invention/compositions produced according to the invention may also comprise a content of so-called mixed esters, preferablybut not exclusivelyfrom the group of 3-glycidyloxypropyldi(-2-ethylhexoxy)monomethoxysilane, 3-glycidyloxypropyldi(-2-ethylhexoxy)monoethoxysilane, 3-glycidyloxypropylmono(-2-ethylhexoxy)dimethoxysilane and 3-glycidyloxypropylmono(-2-ethylhexoxy)diethoxysilane, suitably with a content of mixed ester of 10% by weight, preferably 5% by weight, wherein all components in a composition according to the invention/compositions produced according to the invention sum to 100% by weight.

[0040] The present invention further provides for the use of at least one of the 3-glycidyloxypropyltrialkoxysilanes according to the invention having long-chain alkoxy groups according to formula (I) and formula (II), in particular glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane, for functionalization of rubber, wherein the 3-glycidyloxypropyltrialkoxysilane having long-chain alkoxy groups, in particular 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane, is preferably used for chain termination in an anionic polymerization. It is preferable to employ at least one of the recited 3-glycidyloxypropyltrialkoxysilanes having long-chain alkoxy groups for functionalization/modification of rubber.

[0041] It is furthermore advantageous to use a rubber modified with at least one 3-glycidyloxypropyltrialkoxysilane having long-chain alkoxy groups of formula (I) and of formula (II), preferably 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane, in rubber mixtures; in particular an S-SBR or BR modified with 3-glycidyloxypropyltri(-2-ethylhexoxy)silane or 3-glycidyloxypropyltri(-2-propylheptoxy)silane in rubber mixtures for treads in tyres.

[0042] The novel compounds/compositions according to the invention may thus be employed in advantageous fashion for examplebut not exclusivelyas a coupling reagent in the production of functional polymers, such as butadiene rubber, or for solution styrene-butadiene rubber.

[0043] The present invention is elucidated in detail by the examples which follow, without restricting the subject-matter of the invention:

[0044] Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only, and are not intended to be limiting unless otherwise specified.

EXAMPLES

[0045] Chemicals Used:

[0046] Dynasylan GLYMO (3-glycidyloxypropyltrimethoxysilane), Evonik Resource Efficiency GmbH

[0047] Titanium tetrabutoxide, Sigma-Aldrich

[0048] 2-ethylhexanol, Sigma-Aldrich

[0049] 2-propylheptanol, Evonik Performance Materials GmbH

[0050] Analytical Methods:

[0051] NMR Measurements:

[0052] Instrument: Bruker

[0053] Frequency: 100.6 MHz (.sup.13C-NMR)

[0054] Scans: 1024 (.sup.13C-NMR)

[0055] Temperature: 296 K

[0056] Solvent: CDCl.sub.3

[0057] Standard: tetramethylsilane

[0058] Gas Chromatography Determination of Alcohol:

[0059] All figures should be understood as guide values. Columns of similar polarity, for example from other manufacturers, are permitted. If the separation is demonstrably also achievable with an instrument having a packed column, this is also permitted.

[0060] In the handling of the samples, the moisture sensitivity thereof should be noted.

TABLE-US-00001 Instrument: Capillary gas chromatograph with TCD and integrator e.g. HP 5890 with HP 3396 integrator Separation column: Capillary column Length: 25 m Internal diameter: 0.20 mm Film thickness: 0.33 mm Stationary phase: HP Ultra 1 Temperatures: Column oven: 120 C. - 2 min - 10/min - 275 C. - 8 min injector: 250 C. Detector: 280 C. Carrier gas: Helium Flow: about 1 ml/min Split ratio: ca. 1:100 Sample injected: 0.4 ml

[0061] Evaluation is effected by standardization to 100 area %.

Example 1

[0062] Dynasylan GLYMO (23.6 g, 100 mmol, 1.0 eq.), 2-ethylhexanol (39.1 g, 300 mmol, 3.0 eq.) and Ti(OnBu).sub.4 (23.6 mg, 0.1% by weight based on Dynasylan GLYMO) were initially charged and heated to 130 C. for 12 h. The product was then separated from volatile constituents at 130 C. and 0.1 mbar. The reaction product obtained (56.1 g) was a pale yellowish, slightly viscous liquid.

[0063] The reaction product was analysed by means of .sup.13C NMR. The analysis demonstrates that the reaction product obtained was a 3-glycidyloxypropyltri(-2-ethylhexoxy)silane.

[0064] .sup.13C-NMR (100 MHz, CDCl.sub.3): =74.0 (s, 1C), 71.5 (s, 1C), 64.9 (s, 3C), 50.9 (s, 1C), 44.4 (s, 1C), 41.9 (s, 3C), 30.2 (s, 3C), 29.2 (s, 3C), 23.5 (s, 3C), 23.2 (s, 3C), 14.1 (s, 3C), 11.2 (s, 3C), 6.4 (s, 1C) ppm.

[0065] The transesterification yield was 95%, i.e. 95% of the methoxy groups of the employed Dynasylan GLYMO were replaced, i.e. transesterified, with 2-ethylhexoxy groups in accordance with the invention.

Example 2

[0066] Dynasylan GLYMO (23.6 g, 100 mmol, 1.0 eq.), 2-ethylhexanol (50.1 g, 390 mmol, 3.9 eq.) and Ti(OnBu).sub.4 (23.6 mg, 0.1% by weight based on Dynasylan GLYMO) were initially charged and heated to 130 C. for 16 h. The product was then separated from volatile constituents at 130 C. and 0.1 mbar. The reaction product obtained (57.9 g) was a pale yellowish, slightly viscous liquid.

[0067] The reaction product was analysed by means of .sup.13C NMR. The analysis demonstrates that the reaction product obtained was a 3-glycidyloxypropyltri(-2-ethylhexoxy)silane.

[0068] .sup.13C-NMR (100 MHz, CDCl.sub.3): =74.0 (s, 1C), 71.5 (s, 1C), 64.9 (s, 3C), 50.9 (s, 1C), 44.4 (s, 1C), 41.9 (s, 3C), 30.2 (s, 3C), 29.2 (s, 3C), 23.5 (s, 3C), 23.2 (s, 3C), 14.1 (s, 3C), 11.2 (s, 3C), 6.4 (s, 1C) ppm.

[0069] The transesterification yield was 98%, i.e. 98% of the methoxy groups of the employed Dynasylan GLYMO were replaced, i.e. transesterified, with 2-ethylhexoxy groups in accordance with the invention.

Example 3

[0070] Dynasylan GLYMO (23.6 g, 100 mmol, 1.0 eq.), 2-propylheptanol (47.5 g, 300 mmol, 3.0 eq.) and Ti(OnBu).sub.4 (23.6 mg, 0.1% by weight based on Dynasylan GLYMO) were initially charged and heated to 130 C. for 12 h. The product was then separated from volatile constituents at 130 C. and 0.1 mbar. The reaction product obtained (59.0 g) was a pale yellowish, slightly viscous liquid.

[0071] The reaction product was analysed by means of .sup.13C NMR The analysis demonstrates that the reaction product obtained was a 3-glycidyloxypropyltri(-2-propylheptoxy)silane.

[0072] .sup.13C-NMR (100 MHz, CDCl.sub.3): =73.9 (s, 1C), 71.4 (s, 1C), 65.3 (s, 3C), 50.9 (s, 1C), 44.3 (s, 1C), 40.2 (s, 3C), 33.4 (s, 3C), 32.5 (s, 3C), 31.0 (s, 3C), 26.6 (s, 3C), 22.8 (s, 3C), 20.1 (s, 3C), 14.6 (s, 3C), 14.2 (s, 3C), 6.4 (s, 1C) ppm.

[0073] The transesterification yield was 96%, i.e. 96% of the methoxy groups of the employed Dynasylan GLYMO were replaced, i.e. transesterified, with 2-propylheptoxy groups in accordance with the invention.

Example 4

[0074] Dynasylan GLYMO (23.6 g, 100 mmol, 1.0 eq.), 2-propylheptanol (61.7 g, 390 mmol, 3.9 eq.) and Ti(OnBu).sub.4 (23.6 mg, 0.1%6 by weight based on Dynasylan GLYMO) were initially charged and heated to 130 C. for 18 h. The product was then separated from volatile constituents at 130 C. and 0.1 mbar. The reaction product obtained (60.9 g) was a pale yellowish, slightly viscous liquid.

[0075] The reaction product was analysed by means of .sup.13C NMR. The analysis demonstrates that the reaction product obtained was a 3-glycidyloxypropyltri(-2-propylheptoxy)silane.

[0076] .sup.13C-NMR (100 MHz, CDCl.sub.3): =73.9 (s, 1C), 71.4 (s, 1C), 65.3 (s, 3C), 50.9 (s, 1C), 44.3 (s, 1C), 40.2 (s, 3C), 33.4 (s, 3C), 32.5 (s, 3C), 31.0 (s, 3C), 26.6 (s, 3C), 22.8 (s, 3C), 20.1 (s, 3C), 14.6 (s, 3C), 14.2 (s, 3C), 6.4 (s, 1C) ppm.

[0077] The transesterification yield was 99%, i.e. 99% of the methoxy groups of the employed Dynasylan GLYMO were replaced, i.e. transesterified, with 2-propylheptoxy groups in accordance with the invention.

[0078] Numerous modifications and variations on the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.