Process for preparing tris[3-(alkyldialkoxysilyl)propyl]isocyanurates

Abstract

A process can prepare an isocyanurate compound by hydrosilylation. The compound is a tris[3-(trialkoxysilyl)propyl] isocyanurate, a tris[3-(alkyldialkoxysilyl)propyl] isocyanurate, and/or a tris[3-(dialkylalkoxysilyl)propyl] isocyanurate, The process includes (A) preparing a mixture of at least one carboxylic acid, a platinum catalyst, and 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione; (B) heating the mixture to a temperature in the range of 40 to 140 C.; (C) adding at least one H-silane among a hydrotrialkoxysilane, a hydroalkyldialkoxysilane, and a hydrodialkylalkoxysilane to the mixture; (D) adding at least one alcohol to the mixture prepared in step (C); and (E) isolating the isocyanurate compound.

Claims

1. A process for preparing a tris[3-(alkyldialkoxysilyl)propyl]isocyanurate of the formula: ##STR00005## comprising the following steps: (A) preparing a mixture comprising at least one carboxylic acid, a platinum catalyst and 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione of the formula: ##STR00006## (B) heating the mixture prepared in step (A) to a temperature in the range of 40 C.-140 C.; (C) adding a hydrosilane of the formula: ##STR00007## to the mixture prepared in step (B); (D) adding at least one alcohol to the mixture prepared in step (C); and (E) isolating the tris[3-(alkyldialkoxysilyl)propyl]isocyanurate of the formula above.

2. The process according to claim 1, wherein the molar ratio of the hydrosilane to the at least one alcohol is 1:0.005-0.3.

3. The process according to claim 1, wherein the molar ratio of the hydrosilane to the platinum catalyst is 1:0.000000001-0.0001.

4. The process according to claim 1, wherein the molar ratio of the hydrosilane to the at least one carboxylic acid is 1:0.001-0.03.

5. The process according to claim 1, wherein the molar ratio of the hydrosilane to 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione is 1:0.1-1.

6. The process according to claim 1, wherein the at least one carboxylic acid is selected from the group consisting of benzoic acid, propionic acid, 2,2-dimethylpropionic acid, 3,5-di-tert-butylbenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid and acetic acid.

7. The process according to claim 1, wherein the at least one alcohol is a C.sub.1-C.sub.10 alcohol.

8. The process according to claim 1, wherein the at least one alcohol is selected from the group consisting of methanol, ethanol, tert-butanol, benzyl alcohol and diglycol monomethyl ether.

9. The process according to claim 1, wherein the at least one alcohol is ethanol.

10. The process according to claim 1, wherein the platinum catalyst is selected from the group consisting of a Karstedt catalyst, a hexachloroplatinum(IV) acid and platinum adsorbed on a solid support.

11. The process according to claim 1, wherein the platinum catalyst is selected from the group consisting of a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in the form of a Karstedt catalyst in xylene or toluene with a 0.5%-5% w/w platinum(0) content, hexachloroplatinum(IV) acid dissolved in acetone and platinum adsorbed on activated carbon.

12. The process according to claim 1, wherein the platinum catalyst is a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in the form of a Karstedt catalyst in xylene or toluene with a 0.5%-5% w/w platinum(0) content.

13. The process according to claim 1, wherein the process further comprises performing step (C) at a temperature in the range of 86 C.-120 C.

14. The process according to claim 1, wherein the process further comprises performing step (D) at a temperature in the range of 96 C.-111 C.

15. The process according to claim 1, wherein the process further comprises recovering the platinum catalyst from the mixture formed in step (D) prior to performing step (E).

16. The process according to claim 1, wherein the process further comprises performing step (E) via distillation at a temperature in the range of 45 C.-150 C. and at a pressure less than 1 bar.

17. The process according to claim 1, wherein at least 90 mol % of the allyl groups in the 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione are converted by hydrosilylation to 3-(alkyldialkoxysilyl)propyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) Any ranges mentioned herein below include al values and subvalues between the lowest and highest limit of this range.

(2) It has been found here to be particularly advantageous that the present process is preferably conducted with a homogeneous platinum(0) complex catalyst, especially a Karstedt catalyst, a Speier catalyst, hexachloroplatinum(IV) acid or a supported, i.e. heterogeneous, Pt catalyst, for example Pt on activated carbon. In addition, a Karstedt catalyst is preferably used in the form of a platinum(0) complex catalyst solution, especially dissolved in xylene or toluene.

(3) The present procedure also makes it possible to reduce the content of Pt catalyst/the Pt loss, and hence to save costly Pt. Moreover, it has been found to be particularly advantageous in the present process to use a carboxylic acid from the group of benzoic acid, 3,5-di-tert-butylbenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, 2,2-dimethylpropionic acid, propionic acid and/or acetic acid.

(4) A product mixture obtained by the present process is suitably worked up by distillation, optionally under reduced pressure, and the desired (target) product is obtained.

(5) In the case of use of a heterogeneous catalyst, the latter can suitably be separated from the product mixture prior to the distillation, for example by filtration or centrifugation, and this Pt catalyst thus recovered can advantageously be recycled into the process.

(6) For instance, the target product is obtained as bottom product in the distillation conducted after the reaction and, if necessary, after the removal of a heterogeneous catalyst; the target product is not distilled over in the distilative workup and is obtained as a colourless bottom product.

(7) In the present process, the double bonds of the olefin component used here can advantageously be virtually completely hydrosilylated, advantageously giving rise to only a very low level of by-products.

(8) Furthermore, the present process, i.e. that according to the invention, can advantageously be conducted without separate addition of an aliphatic or aromatic hydrocarbon as solvent or diluent, and with only a small proportion of the carboxylic acid (co-)catalyst component which remains in the target product.

(9) The present Invention thus provides a process for preparing a tris[3-(alkoxysilyl)propyl]isocyanurate from the group of tris[3-(trialkoxysilyl)propyl] isocyanurate, tris[3-(alkyldialkoxysilyl)propyl] isocyanurate and tris[3-(dialkylalkoxysilyl)propyl] isocyanurate by hydrosilylatlon,

(10) by

(11) In step A initially charging a mixture comprising 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione as olefin component, at least one carboxylic acid and a Pt catalyst, heating the mixture to a temperature of 40 to 140 C., in step B adding at least one hydroalkoxysilane from the group of hydrotrialkoxysilane, hydroalkyldialkoxysilane, hydrodialkylalkoxysilane [called H-silane(s) for short] to the mixture from step A while mixing, in step C leaving the mixture from step B to react while mixing, with addition of at least a defined amount of alcohol to the mixture as further cocatalyst, and in step D working up the product mixture thus obtained.

(12) In the process according to the invention. H-silane is advantageously used relative to olefin component in a molar ratio of 1:0.1 to 1, preferably of 1:0.2 to 0.4, especiallyto give just a few of the possible intermediate values here that will be clear or derivable for the person skilled in the art from the figures above and the present figures, in a representative manner and by way of example1:0.13, 1:0.15, 1:0.18, 1:0.23, 1:0.25, 1:0.28, 1:0.3, 1:0.33, 1:0.35, 1:0.38.

(13) The H-silane used here is preferably hydrotrimethoxysilane (TMOS), hydrotriethoxysilane (TEOS), methyidiethoxysilane (DEMS), methyldimethoxysilane (DMMS), dimethylethoxysilane (DMES) and/or dimethylmethoxysilane (MDMS).

(14) Moreover, in the process according to the invention, the olefin component used is 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione.

(15) Advantageously, in the process according to the invention, it is preferable to use H-silane relative to alcohol in a molar ratio of 1:0.005 to 0.3, preferably 0.01 to 0.2, preferably 1:0.02 to 0.18, more preferably 1:0.03 to 0.15, even more preferably 1:0.04 to 0.1, especially 1:0.05 to 0.06. Preferably, for this purpose, at least one alcohol is selected from the group of the C.sub.1-C.sub.10 alcohols, more preferably at least one from the group of tert-butanol, ethanol, methanol, benzyl alcohol and diglycol monomethyl ether.

(16) Moreover, in the process according to the invention. H-silane is advantageously used relative to Pt in a molar ratio of 1:110.sup.4 to 110.sup.9, preferably 1:110.sup.5 to 110.sup.8, especially of 1:110.sup.5 to 910.sup.4.

(17) The Pt catalyst used here is suitably a heterogeneous Pt catalyst, preferably Pt applied to a solid catalyst support, especially Pt on activated carbon, or a homogeneous Pt catalyst, preferably a Pt complex catalyst, such as hexachloroplatinum(IV) acid, also called Speier catalyst, especially hexachloroplatinum(IV) acid dissolved in acetone, preferably a Pt(0) complex catalyst, more preferably a Karstedt catalyst, even more preferably a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, especially a Karstedt catalyst in xylene or toluene with a Pt(0) content of 0.5% to 5% by weight. Such a solution generally contains a platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex dissolved in xylene or toluene, and a solution used in accordance with the invention is advantageously used in dilute form and preferably contains a Pt content of 0.5% to 5% by weight. Thus, in the process according to the invention, it is advantageous to use a Pt catalyst from the group of Karstedt catalyst, especially a Karstedt catalyst solution, preferably platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in xylene or toluene with a Pt(0) content of 0.5% to 5% by weight, hexachloroplatinum(IV) acid, preferably Speier catalyst, especially hexachloroplatinum(IV) acid dissolved in acetone, or Pt supported on activated carbon.

(18) Further, in the process according to the invention, H-silane is preferably used relative to carboxylic acid in a molar ratio of 1:110.sup.3 to 3010.sup.3, more preferably 1:110.sup.3 to 1010.sup.3, especially of 1:210.sup.3 to 810.sup.3.

(19) For this purpose, the carboxylic acid is preferably selected from the group of benzoic acid, 3,5-di-tert-butylbenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, propionic acid, 2,2-dimethylpropionic acid, acetic acid.

(20) It is thus possible, in general, to execute the process according to the inventionwith all its possible combinations of the features detailed in the present descriptionas follows:

(21) For the performance of the hydrosilylation according to the invention for preparation of a tris[3-(alkoxysilyl)propyl] isocyanurate, a stirred reactor with metering apparatus, heating/cooling apparatus, reflux apparatus and distillation apparatus, suitably under protective gas, for example nitrogen, in step A is initially charged with a mixture comprising 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione as olefin component, at least one carboxylic acid, preferably benzoic acid, 3,5-di-tert-butylbenzoic acid, 3,5-di-tert-butyl-4-hydroxybenzoic acid, propionic acid, 2,2-dimethylpropionic acid and/or acetic acid, and a Pt catalyst, suitably a Speier catalyst, preferably hexachloroplatinum(IV) acid in acetone or hexachloroplatinum(IV) acid hexahydrate dissolved in acetone or a Karstedt catalyst, the latter preferably being used in the form of a platinum(0) complex catalyst solution, or Pt on activated carbon, and the mixture is heated to a temperature of 40 to 140 C., preferably to a temperature of 50 to 120 C., in step B at least one hydroalkoxysilane from the group of hydrotrialkoxysilane, hydroalkyldialkoxysilane, hydrodialkylalkoxysilane [called H-silane(s) for short] is added to the mixture from step A while mixing. In step C the mixture from step B is left to react while mixing, with addition of at least a defined amount of alcohol to the mixture as further cocatalyst, preferably under temperature control and over 1 to 10 or more hours, where the metering time may clearly be dependent on the batch size and the reactor design; it is suitably possible to allow further reaction while mixing, for example at a temperature of 60 to 100 C., especially over 0.5 to 2 hours; the alcohol can also be added separately. in the subsequent step D the product mixture thus obtained is worked up.

(22) Thus, in present processes, the respective feedstocks are preferably used in a well-defined molar ratio: H-silane to olefin component in a molar ratio of 1:0.1 to 1 H-silane to alcohol in a molar ratio of 1:0.01 to 02 H-silane to Pt in a molar ratio of 1:110.sup.7 to 110.sup.9. H-silane to carboxylic acid in a molar ratio of 1:110.sup.3 to 3010.sup.3

(23) In addition, the Karstedt catalyst solution used is preferably prepared from a conventional Karstedt catalyst concentrate (platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiioxane complex, platinum content: 20.37% by weight) (also called Karstedt concentrate hereinafter for short). the concentrate preferably being adjusted to a Pt content of 0.5% to 5% by weight by the addition of xylene or toluene.

(24) A product mixture thus obtained is a suitably worked up by distillation to obtain the desired (target) product. For this purpose, the distillation is preferably conducted commencing at 45 C. to 150 C. and a reduced pressure (vacuum distillation at less than 1 bar and falling, especially not more than 0.1 bar), wherein low boilers that are present in particular, for example carboxylic acid, alcohol, excess H-silane and any olefin component still present are removed from the product mixture. If a heterogeneous Pt catalyst is used for the performance of the process according to the invention, the heterogeneous Pt catalyst can be separated from the product mixture obtained after the reaction in the course of the product workup, i.e. prior to the distillation step, for example by filtration or centrifugation, and advantageously be recycled back into the process.

(25) It is thus advantageously possible to prepare tris[3-(alkoxysilyl)propyl] isocyanurates obtainable in accordance with the invention in comparatively high yield and selectivity, i.e. with only small proportions of by-products, even on the industrial scale in a simple and economically viable manner.

(26) The examples which follow provide additional illustration of the present invention without restricting the subject-matter:

EXAMPLES

(27) Analytical Methods:

(28) NMR Measurements:

(29) Instrument: Bruker

(30) Frequency: 500.1 MHz (.sup.1H NMR)

(31) Scans: 32

(32) Temperature: 303 K

(33) Solvent: CDCl.sub.3

(34) Standard: 0.5% TMS (tetramethylsilane)

(35) Explanations are given below with regard to naming of target product and by-products formed in the synthesis with respect to the present .sup.1H NMR evaluations using the example of the structural formula of a tris[3-(trialkoxysilyl)propyl] isocyanurate. The determinations of selectivities with respect to tris[3-(methyldialkoxysilyl)propyl] isocyanurate and tris[3-(dimethylalkoxysilyl)propyl]isocyanurate were conducted analogously and are listed in the tables for Examples 6 and 7.

(36) ##STR00001##
in the target product: functional group S1 (SiCH.sub.2)

(37) ##STR00002##
in the so-called allyl derivative: functional group A1

(38) ##STR00003##
in the so-called propyl derivative: functional group P1

(39) ##STR00004##
in the so-called isopropyl derivative: functional group I1

(40) The experiments were evaluated using the product formed in the hydrosilylation of the 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione. The more allylic double bonds were converted to the target product and the fewer secondary components were formed, the better the product quality and the performance/selectivity of the catalyst system. A high selectivity is very important because the secondary components can be removed by distillation from the target product only with a very high level of complexity, if at all.

(41) The 1H NMR spectra were evaluated using the hydrogen atoms included in the structural formula drawings. The hydrosilylation gives rise to SiCH.sub.2 groups that are characteristic of the target product. The SiCH.sub.2 groups were identified with S1, the allylic groups (CCH.sub.2 group) with A1, the propyl group (C.sub.3H.sub.7 group) with P1 and the isopropyl group with I1. The evaluation of the 1H NMR spectra and the calculation of the functional groups was shown after each experiment in the tables. The evaluated signals from the .sup.1H NMR form triplets (t) for the S1 and P1 group, double doublets (dd) for the A1 group, and doublets (d) for the 11 group.

(42) Chemicals Used:

(43) Karstedt concentrate (platinum(0) 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, platinum content: 20.37% by weight), HERAEUS

(44) Acetone, pure, LABC Labortechnik

(45) Hexachloroplatinum(IV) acid hexahydrate, platinum content 40% by weight, HERAEUS

(46) Platinum-activated carbon, hydrogenation catalyst, platinum content 10% by weight, MERCK

(47) Benzyl alcohol, puriss, SIGMA ALDRICH

(48) Diethylene glycol monomethyl ether >98% by weight, MERCK

(49) Xylene Technical, VWR Chemicals

(50) Dynasylan TMOS (trimethoxysilane), EVONIK Industries

(51) Dynasylan TEOS-H (triethoxysilane). EVONIK Industries

(52) Dynasylan DEMS (methyldiethoxysilane), EVONIK Industries

(53) Dynasylan DMES (dimethylethoxysilane), EVONIK Industries

(54) TIACROS (1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione), EVONIK Industries

(55) Benzoic acid 99.5% by weight, ROTH

(56) 3,5-Di-tert-butylbenzoic acid >98.0% by weight, TOKYO CHEMICAL INDUSTRY

(57) 3,5-Di-tert-butyl-4-hydroxybenzoic acid, >98.0% by weight, TOKYO CHEMICAL INDUSTRY

(58) Acetic acid, 99% by weight, SIGMA-ALDRICH

(59) Methanol 99.5% by weight, MERCK

(60) Ethanol 99.8% by weight, ROTH

(61) tert-Butanol, 99.0% by weight (for synthesis), ROTH

(62) Chloroform-d1 (CDCl.sub.3)+0.5% by weight of TMS, DEUTERO

(63) Benzene-d6, DEUTERO

(64) Tetramethylsilane, DEUTERO

(65) Preparation of Karstedt-Catalyst No. 1 with Platinum Content 2% by Weight in Xylene:

(66) In a 0.2 l glass bottle, 9.8 g of Karstedt concentrate (platinum(0) 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, platinum content 20.37%) were mixed with 90.2 g of xylene.

(67) Preparation of Karstedt-Catalyst No. 2 with Platinum Content 2% by Weight in Toluene:

(68) In a 0.2 l glass bottle, 9.8 g of Karstedt concentrate (platinum(0) 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, platinum content 20.37% by weight) were mixed with 90.2 g of toluene.

(69) Preparation of Karstedt-Catalyst No. 3 with Platinum Content 0.4% by Weight:

(70) In a 0.1 l glass bottle, 196.4 mg of Karstedt concentrate (platinum(0) 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, platinum content 20.37% by weight) were mixed with 9.8 g of toluene.

(71) Preparation of Catalyst 4 from Hexachloroplatinum(IV) Acid Hexahydrate Solution in Acetone with Pt Content 2.34% by Weight:

(72) In a 12 l plastic vessel, 530 g of H.sub.2PtCl.sub.66H.sub.2O were dissolved in 9.8 l of acetone. The catalyst solution thus prepared was used after maturing for 8 weeks.

(73) Comment on the Comparative Examples which Follow:

(74) The synthesis in ampoules described in U.S. Pat. No. 5,986,124 cannot be conducted on the industrial scale. In order that the experiments can be better compared with the inventive examples, the experiments were conducted in a stirred tank or flask. Furthermore, in the examples in U.S. Pat. No. 5,986,124, different unsaturated compounds were used, and so a direct comparison with the present invention would not be possible; thus, TAICROS was used in the comparative examples which follow.

Comparative Example 1: (Based on Example 1 from U.S. Pat. No. 5,986,124)

(75) 0.2003 mol (24.5 g) of Dynasylan TMOS, 0.1 ml of Catalyst No. 1, a further 40.0 g of toluene as additional solvent/diluent, 0.0665 mol (16.6 g) of TAICROS and 0.4 ml of acetic acid were initially charged in a 0.25 l stirred apparatus with jacketed coil condenser and stirred in an oil bath heated to 53-55 C. for 2.5 hours. This gave 79.9 g of incompletely converted and colourless bottom product. The volatile components were not removed.

(76) Evaluation of the .sup.1H NMR spectrum with regard to Comparative Example 1:

(77) TABLE-US-00001 Solvent: N CDCl.sub.3 + 0.5% Signal at Integral Number of TMS [ppm] I protons I/N % (mol) S1 0.64 100.00 2 50.00 45.8 A1 5.27 117.28 2 58.64 53.7 P1 0.93 0.81 3 0.27 0.3 I1 1.00 0.61 3 0.20 0.2 Result: 45.8% of the allyl groups were converted by hydrosilylation to trimethoxysilylalkyl groups (cf. S1). 53.7% of the allyl groups (A1) have not been converted, and 0.3% propyl groups (P1) and 0.2% isopropyl groups (I1) that contaminate the product have formed. The reaction is incomplete.

Comparative Example 2: (Based on Example 1 from U.S. Pat. No. 5,986,124)

(78) 0.2003 mol (32.9 g) of Dynasylan TEOS-H, 0.1 ml of Catalyst No. 3, a further 40.0 g of toluene as additional solvent/diluent, 0.0665 mol (16.6 g) of TAICROS and 0.4 ml of acetic acid were initially charged in a 0.25 l stirred apparatus with reflux condenser and stirred in an oil bath heated to 50-57 C. for 2.5 hours. This gave 88.2 g of incompletely converted and colourless bottom product. The volatile components were not removed.

(79) Evaluation of the .sup.1H NMR spectrum with regard to Comparative Example 2:

(80) TABLE-US-00002 Solvent: N CDCl.sub.3 + 0.5% Signal at Integral Number of TMS [ppm] I protons I/N % (mol) S1 0.64 100.00 2 50.00 86.2 A1 5.26 14.59 2 7.30 12.6 P1 0.94 0.33 3 0.33 0.6 I1 1.06 0.35 3 0.35 0.6 Result: 86.2% of the allyl groups were converted by hydrosilylation to trimethoxysilylalkyl groups (cf. S1). 12.6% of the allyl groups (A1) have not been converted, and 0.6% propyl groups (P1) and 0.6% isopropyl groups (I1) that contaminate the product have formed. The reaction is incomplete.

Comparative Example 3: (with Acetic Acid Only, No Addition of Alcohol)

(81) 1.2 mol of DYNASYLAN TMOS and 02 g of Catalyst No. 1 (corresponding to 0.0205 mmol of Pt) were initially charged in a 0.5 l stirred apparatus with reflux condenser, metering apparatus. At a temperature of 76-91 C., a mixture consisting of 0.33 mol of TAICROS and 6.77 mmol of acetic acid was metered in within 1 h. Thereafter, the mixture was left to react further at about 87-92C for about 1 further hour. Subsequently, 55.0 g of low boilers were removed at 90-120 C. and a pressure of <0.1 mbar. This gave 170.7 g of incompletely converted, colourless bottom product.

(82) Evaluation of the .sup.1H NMR spectrum with regard to Comparative Example 3:

(83) TABLE-US-00003 Solvent: N CDCl.sub.3 + 0.5% Signal at Integral Number of TMS [ppm] I protons I/N % (mol) S1 0.66 100.00 2 50.00 73.8 A1 5.25 34.79 2 17.40 25.7 P1 0.94 0.61 3 0.20 0.3 I1 1.01 0.43 3 0.14 0.2 Result: 73.8% of the allyl groups were converted by hydrosilylation to trirnethoxysiylalkyl groups (cf. S1). 25.7% of the allyl groups (A1) have not been converted, and 0.3% propyl groups (P1) and 0.2% isopropyl groups (I1) that contaminate the product have formed. The reaction is incomplete.

Comparative Example 4

(84) 1.2 mol of Dynasylan TMOS, 0.2 g of Karstedt catalyst (corresponding to 0.0205 mmol of Pt), 34.38 mmol of methanol and 6.55 mmol of benzoic acid were initially charged in a 0.5 l stirred apparatus with reflux condenser, metering apparatus. At a temperature of 73-82 C., 0.33 mol of TAICROS was metered in within 1 hour. Thereafter, the mixture was left to react further at 81 C. for another 1 hour. Subsequently, 89.5 g of low boilers were removed at 35-127 C. and a pressure of <0.1 mbar. This gave 134.2 g of incompletely converted and colourless bottom product.

(85) Evaluation of the .sup.1H NMR spectrum from Comparative Example 4:

(86) TABLE-US-00004 Solvent: N CDCl.sub.3 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.66 100.00 2 50.00 42.5 A1 5.25 134.10 2 67.05 57.0 P1 0.94 1.24 3 0.41 0.4 I1 1.01 0.36 3 0.12 0.1 Result: 42.5% of the allyl groups were converted by hydrosilylation with TMOS to trimethoxysilylalkyl groups (cf. S1). 57.0% of the allyl groups (A1) were not converted. 0.4% propyl groups (P1) and 0.1% isopropyl groups (I1) that contaminate the product were formed. The conversion of the allyl groups is incomplete, and only a low level of by-products is formed.

Comparative Example 5

(87) 1.2 mol of Dynasylan TMOS, 0.2 g of Karstedt catalyst (corresponding to 0.0205 mmol of Pt) and 34.38 mmol of methanol were initially charged in a 0.5 l stirred apparatus with reflux condenser, metering apparatus. At a temperature of 70-87 C., a mixture consisting of 0.33 mol of TAICROS and 6.55 mmol of benzoic acid was metered in within 1 hour. Thereafter, the mixture was left to react further at 81 C. for another 1 hour. Subsequently, 41.5 g of low boilers were removed at 61-121 C. and a pressure of <0.1 mbar. This gave 183.0 g of Incompletely converted and colourless bottom product.

(88) TABLE-US-00005 Evaluation of the 1H NMR spectrum from Comparative Example 5: Solvent: N CDCl.sub.3 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.66 100.0 2 50.00 81.5 A1 5.25 21.75 2 10.87 17.7 P1 0.94 1.09 3 0.36 0.6 I1 1.01 0.38 3 0.13 0.2 Result: 81.5% of the allyl groups were converted by hydrosilylation with TMOS trimethoxysilylalkyl groups (cf. S1). 17.7% of the allyl groups (A1) were not converted. 0.6% propyl groups (P1) and 0.2% isopropyl groups (I1) that contaminate the product were formed. The conversion of the allyl groups is incomplete, and only a low level of by-products is formed.

Comparative Example 6

(89) 0.33 mol (83.1 g) of TAICROS, 0.2 g of Catalyst No. 1 (corresponding to 0.0205 mmol of Pt) and 6.79 mmol (1.7 g) of 3,5-di-tert-butyl-4-hydroxybenzoic acid were initially charged in a 0.5 l stirred apparatus with reflux condenser, metering apparatus. At a temperature of 91-111 C., 1.2 mol (146.6 g) of Dynasylan TMOS were supposed to be metered in. The hydrosilylation is highly exothermic and, after metered addition of 18 g of Dynasylan TMOS, the temperature had already risen from 91 to 97 C. within 9 minutes. Once a further 72 g of Dynasylan TMOS had been metered in within 27 minutes and the temperature had risen to 108 C. it was not possible to detect any exothermicity in the course of further addition of Dynasylan TMOS. The reaction mixture cooled down from 108 to 89 C. within a few minutes. The experiment was therefore stopped after metered addition of a total of 90 g of Dynasylan TMOS; in other words, the reaction stopped and the conversion in this procedure thus remained correspondingly incomplete. 68 g of Dynasylan TMOS were not metered in.

(90) Note:

(91) The present comparative experiments for preparation of tris[3-(alkoxysilyl)propyl] isocyanurates by hydrosilylation of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TAICROS) in the presence of a Pt catalyst system composed of Pt catalyst and carboxylic acid show that a comparatively low conversion of the double bond of well below 90 mol % is discovered when a mixture of H-silane, Pt catalyst, carboxylic acid and TAICROS is used, heated and reacted as such H-silane and Pt catalyst are initially charged and heated and a mixture of TAICROS and carboxylic acid is metered in H-silane, Pt catalyst and alcohol are initially charged and heated and a mixture of TAICROS and carboxylic acid is metered in H-silane, Pt catalyst, carboxylic acid and alcohol are initially charged and heated and TAICROS is metered in or TAICROS, Pt catalyst and carboxylic acid are initially charged and heated and H-silane is metered in.

Example 1

(92) 0.33 mol of TAICROS, 0.2 g of Catalyst No. 1 (corresponding to 0.0205 mmol of Pt) and 6.79 mmol of 3,5-di-tert-butyl-4-hydroxybenzoic acid were initially charged in a 0.5 l stirred apparatus with reflux condenser, metering apparatus. At a temperature of 91-111 C., 0.82 mol of Dynasylan TMOS was metered in within 45 minutes. Subsequently, 33.7 mmol of tert-butanol were added and, at a temperature of 96-111 C. 0.38 mol of Dynasylan TMOS was metered in within 20 minutes. Thereafter, the mixture was left to react further at about 109-120 C. for about 1 further hour. Subsequently, 24.3 g of low boilers were removed at about 104-120 C. and a pressure of <0.1 mbar. This gave 204.9 g of completely converted and colourless bottom product. As well as the target product, the following trace impurities were evaluated via the .sup.1H NMR spectra:

(93) Evaluation of the .sup.1H NMR spectrum of example 1:

(94) TABLE-US-00006 Solvent: N CDCl.sub.3 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.66 100.0 2 50.00 97.3 A1 5.25 0.02 2 0.01 <0.1 P1 0.94 2.09 3 0.70 1.4 I1 1.01 2.01 3 0.67 1.3 Result: 97.3% of the allyl groups were converted by hydrosilylation with TMOS to trimethoxysilyl groups. Allyl groups (A1) are still longer detectable in very small amounts. 1.4% propyl groups (P1) and 1.3% isopropyl groups (I1) that contaminate the product were formed. The conversion of the allyl groups is complete, and only a low level of by-products is formed.

Example 2

(95) 0.973 mole TAICROS, 0.6 g catalyst Nr. 1 (0.0615 mmole Pt) and 19.98 mmole acetic acid were placed in a 1.0 l-reactor equipped with stirrer, reflux condenser and dosing device. At a temperature of 72-101 C. 2.33 mole Dynasylan TEOS-H were added within 42 minutes. Subsequently 33.7 mmole ethanol were added and at a temperature of 96-111 C. 1.16 mole Dynasylan TEOS-H were added within 25 minutes. The reaction mixture was heated for another hour to 109-120 C. Then 98.2 g low boiler was removed at 104-140 C. and a pressure of <0.1 mbar. 718.9 g of a colorless product is remaining in the reactor. The composition of the product was analyzed via 1H-NMR analysis:

(96) Results of the .sup.1H-NMR-spectrum of example 2:

(97) TABLE-US-00007 Solvent: N CDCl.sub.3 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.64 100.00 2 50.00 98.77 A1 5.26 2 <0.1 P1 0.94 1.48 3 0.50 0.98 I1 1.06 0.45 3 0.15 0.25 Result: 98.77% of the allylic groups reacted with the Si-H groups and triethoxysiylalkylgroups were formed. Allylic groups which reacted to triethoxysilylalkyl groups (S1). Free allylic groups could not he detected (A1). 0.98% of propyl groups (P1)- and 0.25% iso-propyl groups (I1) were formed as impurities. The conversion of the allylic groups is very high and only small amounts of impurities are formed.

Example 3

(98) 0.167 mole TAICROS, 0.1 g catalyst Nr. 1 (0.01025 mmole Pt) and 1.64 mmole benzoic acid were placed in a 0.5 l-reactor equipped with stirrer, reflux condenser and dosing device. At a temperature of 86-120 C. 0.4 mole Dynasylan DEMS (methyldiethoxysilane) were added within 42 minutes. Subsequently 33.5 mmole ethanol were added and at a temperature of 96-111 C. 0.2 mole Dynasylan DEMS were added within 25 minutes. The reaction mixture was heated for another hour to 106-110 C. Then 12.6 g low boiler are removed at 65-110 C. and a pressure of <0.1 mbar. 108.2 g of a colorless product was remaining in the reactor. The composition of the product was analyzed via 1H-NMR analysis:

(99) Results of the .sup.1H-NMR-spectrum of example 3:

(100) TABLE-US-00008 Solvent: N C.sub.6D.sub.6 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.62 100.00 2 50.00 98.18 A1 5.25 2 <0.1 P1 0.75 2.1 3 0.70 1.37 I1 0.87 0.7 3 0.23 0.45 Result: 98.18% of the allyl groups reacted with the Si-H groups and methyldiethoxysilylalkylgroups were formed. Allylic groups which reacted to methyldiethoxysilylalkyl groups (S1). Free allylic groups could not be detected (A1). 1.37% of propyl groups (P1)- and 0.45% iso-propyl groups (I1) were formed as impurities. The conversion of the allylic groups is very high and only small amounts of impurities are formed.

Example 4

(101) 0.167 mole TAICROS, 0.1 g catalyst Nr. 1 (0.01025 mmole Pt) and 1.64 mmole benzoic acid were placed in a 0.5 l-reactor equipped with stirrer, reflux condenser and dosing device. At a temperature of 56-80 C. 0.4 mole Dynasylan DMES (dimethylethoxysilane) were added within 40 minutes. Subsequently 32.6 mmole ethanol were added and at a temperature of 96-111 C. 0.2 mole Dynasylan DMES were added within 25 minutes. The reaction mixture was heated for another hour to 87-92 C. Then 8.9 g low boiler are removed at 75-120 C. and a pressure of <0.1 mbar. 95.0 g of a colorless product was remaining in the reactor. The composition of the product was analyzed via 1H-NMR analysis:

(102) Results of the .sup.1H-NMR-spectrum of example 4:

(103) TABLE-US-00009 Solvent: N C.sub.6D.sub.6 + 0.5% Signal at Number of TMS [ppm] Integral protons I/N % (mol) S1 0.54 100.00 2 50.00 99.7 A1 5.25 2 <0.1 P1 0.75 0.03 3 0.01 <0.1 I1 0.87 0.4 3 0.13 0.3 Result: 99.7% of the allyl groups reacted with the Si-H groups and dimethylethoxysilylalkylgroups were formed. Allylic groups which reacted to dimethylethoxysilylalkyl groups (S1). Free allylic groups (A1) and propyl groups (P1) could not be detected. 0.3% iso-propyl groups (I1) were formed as impurity. The conversion of the allylic groups is very high and only small amounts of impurities are formed.