United States Patent (19) 11 Patent Number: 4,697,009 Deschler et al. (45) Date of Patent: Sep. 29, 1987

54 N-SILYLPROPYL-N'-ACYL- AND 58 Field of Search ...... 556/421; 544/229; PROCESS FOR THER PRODUCTION 546/14: 548/110; 260/239 BC; 556/414; 540/487 75) Inventors: Ulrich Deschler; Peter Kleinschmit, 56) References Cited both of Hanau; Rudolf Michel, Freigericht, all of Fed. Rep. of U.S. PATENT DOCUMENTS Germany 2,857,430 10/1958 Applegath et al...... 556/421 X 2,907,782 10/1959 Pike ...... 556/421 73 Assignee: Degussa Aktiengesellschaft, 3,793,253 2/1974 Quiring et al...... 556/421 X Frankfurt am Main, Fed. Rep. of 3,803,194 4/1974 Golitz et al...... 556/42 X Germany 3,856,756 12/1974 Wagner et al...... 556/421 X Primary Examiner-Paul F. Shaver 21 Appl. No.: 875,867 Attorney, Agent, or Firm-Cushman, Darby & Cushman 22 Filed: Jun. 18, 1986 57 ABSTRACT The invention is directed to N-silylpropyl-N'-acyl ureas 30 Foreign Application Priority Data and their production from an alkali cyanate, a 3-halo propylsilane and in a given case, a cyclic acidamide. By Jul. 6, 1985 IDE Fed. Rep. of Germany ...... 352.425 heating the compounds of the invention the blocked 5) Int. Cl...... C07F 7/10 function can be set free. 52 U.S. Cl...... 540/487; 556/414; 556/421; 544/229; 546/14: 548/110 16 Claims, 3 Drawing Figures U.S. Patent Sep. 29, 1987 Sheet 1 of 3 4,697,009

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4,697,009 1. 2 attainable time-space yields are unsatisfactory for an N-SILYLPROPYL-N'-ACYL-UREAS AND industrial process. PROCESS FOR THER PRODUCTION The same is true for the process for the production of 3-isocyanatopropylsilanes by gas phase esterification of BACKGROUND OF THE INVENTION 5 3-isocyanatopropyltrichlorosilane with (Ben The invention is directed to N-silylpropyl-N'-acyl nett U.S. Pat. No. 3,651,117) in which the simulta ureas, a process of their production and the setting free neously undesired side reaction of the isocyanate group of the blocked isocyanate function. with the can be suppressed only through an Silanes of the general structure I have large scale significance as coupling agents in material systems 10 industrially expensive procedure. which consist of an inorganic and an organic phase, as The invention is directed to hydrolyzable silanes well as for the modification of OH functional surfaces: having a blocked isocyanate function and a process for their direct production in high yields. (RO)3Si-CH2-CH2-CH2-X (I) Simultaneously the isocyanate group should quite 15 easily be set free by thermolysis. (R4 = CH3, C2H5) The most important functional groups include: SUMMARY OF THE INVENTION X=NH2, -S4- (Si 69), -SH, -Cl, -O- The present invention is directed to N-silylpropyl-N'- CO-C(CH3)=CH2 and 20 acyl-ureas of the formula: -O-CH2-CH-CH2 N / O (III) O A-C-NH-CH6-Si(CH3)(OR)3- The isocyanate function (X=-NCO) represents a 25 particularly valuable : in which On the one hand it can be reacted with numerous x is 0, 1, or 2 H-acidic, monomeric materials (, alcohols, ox R is C1-C6 , straight chain or branched, (2'- imes, and many others) with the formation of newer methoxy)ethyl, , preferably phenyl functional silanes, on the other hand it can also react 30 A is with polymeric resins and rubbers in mutual binding. In contrast to the advantage of the multifold chemical activity there is the disadvantage of the high toxicity of Rl O II the isocyanate group and the cumbersome synthesis of -N-C-R2 the silane (II) in practice (Hedaya U.S. Pat. No. 35 4,130,576): where R is C1-C6 alkyl, straight chain or branched, (RO)3Si-C3H6-NCO (II) R2 is hydrogen, C1-C6 alkyl, straight chain or branched, O In industry therefore there are frequently employed A is blocked alkyl and aryl : (Z. W. Wicks, Progr. Org. Coat. Volume 9, (1981) pages 3-28. CH2-D As blocking agents for the non-silyl containing or / ganic isocyanates there are used, e.g. alcohols (espe m-N cially ), A-dicarbonyl compounds, lactams or . Blocked isocyanates on the one hand are usable 45 CO-(CH2) from aqueous systems and on the other hand relatively inexpensive procedures are sufficient for safely han where y is 1, 2, or 3 and D is -CH2-, >NR1. dling them because of their comparatively low toxicity. These compounds for example, can be applied to In Berger U.S. Pat. No. 3,994,951 there is described a glass fibers from-aqueous solution, which fibers are hydrolyzable silane from which the isocyanate function 50 designed to be worked into synthetic resins. After ther is set free at a temperature of 160° C. which silane is O-methyl-N-trimethoxysilyl-propyl-urethane. mal and/or catalytic treatment the cross-linking can be This compound, however, is little'suited for use as an carried out via the then set free isocyanate. coupling agent in filler reinforced polymer systems for A further subject matter of the invention is a process the reason that the thermolysis only proceeds at rela 55 for the production of compounds of formula (III) by tively high temperatures and the byproduct methanol mixing in an aprotic, polar organic solvent equimolar (flash point: 11 C) formed makes it necessary to take amounts of an alkali cyanate (e.g. or corresponding safety precautions. ), a 3-halopropyl silane of the for The thermolysis of O-methyl-N-trimethoxysilylpro mula: pyl urethane can only be carried out in good yields if 60 there is used very slow thermolysis. The cause of this X-C3H6-Si(CH3)(OR)3. (IV) must be that the thermolysis byproduct methanol is more volatile than the desired 3-isocyanatopropyltrime and a compound of the formula: thoxysilane, so that in the distillative separation of the 65 latter silane from the thermolysis sump the recombina O (V) tion of methanol and 3-isocyantopropyltrimethoxysi I lane in the gas phase can only be prevented if this sepa R2-C-NH-R1 or ration is carried out comparatively slowly. The thus 4,697,009 3 4. -continued phenylacetamide, N-methylcapronic acid , N CH-D (VI) methyllaurylamide, N-methyloleylamide, N-methylpal / mitylamide, N-methylstearylamide, N-methylbenza HN N mide, N-methyltolylamide, cyclic: CO-(CH2) 2-pyrrolidone, 1-N-methyl-hexahydro-1,4-diazepi none of the formula preferably in this sequence, wherein R, R, R2, D, x, and y are as defined above and X is Cl, Br, or I, subse CH-CO quently reacting them with each other at elevated tem M perature, after the end of the reaction and cooling the 10 CH3-N reaction mixture to room temperature filtering off the N / precipitated alkali halide and distilling off the solvent (CH2)3 from the filtrate. The desired product remains behind and can be used 2-piperidone and especially e-caprolactam. without further purification. 15 The desired N-acyl ureas are obtained according to The reactants can be quickly mixed together at room the process of the invention in high yield. temperature, without fear of starting a reaction. Members of this new class of compounds are yellow The reaction is carried out at a temperature of oils as crude products. 100-140° C. within 1-8 hours, preferably 100°-130' C. They can be decomposed thermally at temperatures within 4 hours under a protective gas atmosphere. As of 2135 C. for example according to the following protective gases there are especially suitable equation (2) in which case the decomposition tempera and argon. ture can be lowered still further through the addition of In using the preferably employed cyclic the catalytic amounts of dibutyltin dilaurate. reaction proceeds according to the following scheme: 25 CH2-D (1) / (RO)3Si-CH6-C1 + KOCN + HN N CO-(CH2) 30

CH2-D / (RO)Si-CH6-NH-CO-N - KC N 35 CO-(CH2) CO-(CH2) As solvents there are suitable N,N-dimethylforma There are formed 3-isocyantopropylsilanes of the timide, N,N-dimethylacetamide, N,N,N',N'-tetramethyl formula , N,N,N',N'-tetramethylenediamine, N-methylpyr rolidone, dimethylsulfoxide, hexamethylphosphoric OCN-C3H6-Si(CH3)xOR)3 (VII) . acid triamide. Especially preferred is N,N-dimethylfor mamide. The thermolysis of the compounds of the invention Per mole of silane employed there is used 250-400 ml preferably takes place in a vacuum distillation apparatus of solvent, preferably 300 ml. 45 at pressures of 100 to 6500 Pa, preferably of 200 to 2000 As alkali cyanates there can be used sodium cyanate Pa and a sump temperature between 130' and 160 C. and especially potassium cyanate. Thereby it has been found favorable that, in contrast Suitable silanes are: 3-chloropropyltrimethoxysilane, to the process according to Berger U.S. Pat. No. 3-chloropropyltriethoxysilane, 3-chloropropyltri-i- 3,494,951, the boiling point of the blocking agent as a propoxysilane, 3-chloropropyltri-n-propoxysilane, 3 50 rule is above that of the isocyanatopropylsilane, so that chloropropyltri-t-butoxysilane, 3-chloropropyltri(2'- there does not occur a recombination of the materials in methoxy)ethoxysilane, 3-chloropropyldimethoxyme the gas phase above the distillation sump. thylsilane, 3-chloropropyldiethoxymethylsilane, 3 The thermolysis temperature can be lowered through chloropropylmethoxydimethylsilane, 3-chloropropyle addition of catalytic amounts of dibutyltin dilaurate, thoxydimethylsilane, 3-chloropropyltriphenoxysilane 55 and the corresponding Br- and I-substituted analogous especially 0.5 to 5 mole% based on the acylurea, so that compounds, e.g. 3-bromo-propyltriethoxysilane and thermolysis can be carried out at a temperature of 115 3-iodopropyltri-i-propoxysilane. C. Of these compounds there are preferably employed: The process can comprise, consist essentially of, or 3-chloropropyltrimethoxysilane, 3-chloropropyldime 60 consist of the stated steps with the recited materials. thoxymethylsilane, 3-chloropropyltriethoxysilane, and Unless otherwise indicated all parts and percentages 3-chloropropyldiethoxymethylsilane. are by weight. As amides there are employed: N-methylformamide which is preferred and N-methylacetamide, and the BRIEF DESCRIPTION OF THE DRAWINGS corresponding ethyl-, propyl, and phenyl-substituted 65 FIG. 1 is a mass spectrograph of the compound of amides, N-methylpropionamide, N-methylvaleryla Example 1; mide, and N-methylbutyramide and the corresponding FIG. 2 is the "H-NMR spectrum of the compound of ethyl and phenyl-substituted amides; N-methyl Example 1; and 4,697,009 5 6 FIG. 3 is the IR spectrum of the compound of Exam The molecular weight was confirmed by means of ple i. mass spectrometry, see FIG. 1. The H-NMR spectrum (250 MHz) as well as the IR DETAILED DESCRIPTION spectrum of the product are shown as further character All reactions were carried out in standard laboratory 5 istics of the product in FIGS. 2 and 3. apparatus under a protective gas atmosphere, (e.g. ni EXAMPLES 2 TO 8 trogen) as follows: Equimolar amounts of potassium cyanate, 3-chloro As described in Example 1 there were produced 7 propylalkoxysilane and amide were additional acylureas having hydrolyzable silyl groups mixed in this sequence in dimethylformamide (300 10 by varying the starting material. The amount added and ml/mole alkali cyanate) and heated to about 110' C. the type of material added are set forth in Table 1. Table with stirring within 30 minutes. A slight exotherm was 2 contains data for characterizing the product. All of observed at this temperature, through which the tem the products were oily yellow to light brown liquids perature spontaneously rose up to about 130 C. Stirring which did not have to be purified before use. was continued for a further 4 hours at 130° C. After 15 EXAMPLE 9 cooling the reaction mixture it was filtered off from precipitated alkali chloride and the solvent drawn off. Thermolysis of an Acylurea and Distillative Separation The title compounds then remained as yellow, viscous of the Isocyanatopropylsilane liquids, which did not need any further purification step 150 grams of the product obtained in Example 7 were prior to use. 20 heated in a vacuum distillation apparatus with a Vi greux column at a vacuum of 20 mbars2000 Pa. The EXAMPLE 1 thermal decomposition of the acylurea began at a sump There were added at room temperature under protec temperature of 142 C. 90.2 grams of a colorless liquid tive gas (nitrogen) the following materials in the listed passed over at a head temperature of 107-116 C., sequence within 5 minutes to a 4 liter three neck flask 25 which liquid was identified by H-NMR spectroscopy equipped with a KPG stirrer and water condenser. as a mixture of about 85% of 3-isocyanatopropyltrime 900 ml DMF thoxysilane and 15% e-caprolactam. The reaction sump 235.5 gs3.0 mole potassium cyanate (58.7 grams) consists of e-caprolactam and tris(trime 722.4 gas3.0 mole 3-chloropropyltriethoxysilane thoxysilylpropyl)isocyanurate. By a following vacuum 339.5 gs3.0 mole e-caprolactam 30 distillation at 1 mbar there were obtained from the dis The reaction mixture was then heated to about 110 tillate of the thermolysis 70.6 grams of 3-isocyanato C. within 30 minutes. A slight exotherm occurred at this propyltrimethoxysilane, corresponding to a yield of temperature. The temperature of the reaction was not 73% based on the amount of acylurea employed in the allowed to exceed 130 C. and the reaction proceeded thermolysis. for a total of 4 hours at 130° C. After cooling the reac- 35 tion mixture the precipitated potassium chloride was EXAMPLE 10 filtered off, the precipitate washed three times, each Catalytic Splitting of an Acylurea time with 100 ml of dimethylformamide. The solvent 154.5 grams of the product obtained according to was drawn off from the combined filtrates with the help Example 7 were treated with 5 grams of dibutyltin . of a rotary evaporator. The product remained behind as 40 dilaurate and heated in a vacuum distillation apparatus a yellow, oily liquid and required no further purifica with a Vigruex column at a vacuum of 2 mbars.200 Pa. tion. The decomposition of the acylurea began at a sump Weight: 1033.7 grams corresponding to 95.6% of temperature of 115° C. 100.3 grams of colorless liquid theory, light yellow liquid. passed over at a head temperature of 77-84°C., which 45 liquid according to H-NMR spectroscopy represented C6H32N2OsSi (360.525) a mixture of about 90% isocyanatopropyltrimethoxysi (SL30-3-1) C H N lane and 10% e-caprolactam. By a following vacuum Calculated: 53.30% 8.94% 7.77% distillation there were obtained therefrom 85.8 grams of Found: 53.66% 9.36% 7.33% 50 3-isocyanatopropyltrimethoxysilane, corresponding to a yield of 86% based on the amount of acylurea em ployed in the catalytic decomposition. The entire disclosure of German priority application P 3524215.9 is hereby incorporated by reference. TABLE 1. Starting Materials and Products Amount Silane Alkali- Solvent w Ex. Employed Employed Acidamide cyanate Amount Product (Formula) 2 0.5 mol 3-chloropropyl- N-methyl- Potassium DMF (CH3O)3Si-C3H6-NH-CO-N-CO-H trimethylsilane formanide cyanate (150 ml) CH3

3 0.75 mol 3-chloropropyl- 2-pyrroli- Sodium DMSO CO trimethoxysilane done cyanate (250 ml) / N o (CH3O)3Si-C3H6-NH-CO-N-(CH2)3 4. 0.5 mol 3-bromopropyl- 2-pyrroli- Potassium DMF CO triethoxysilane done cyanate (200 ml) / N 4,697,009

TABLE 1-continued Starting Materials and Products Amount Silane Alkali- Solvent Ex. Employed Employed Acidamide cyanate Armount Product (Formula)

5 0.5 mol 3-iodopropyltri- 2-pyrroli- Sodium DMF CO n-propoxysilane done cyanate (150 ml) - / N (C3H7O)3Si-C3H6-NH-CO-N-(CH2)3 6 not 3-chloropropyl- 2-piperi- Potassium N-Methyl CO trimethoxysilane done cyanate pyrroli- A. / N. done (CH3O3Si-C3H6-NH-CO-N-(CH2)4 (300 ml) 7 mol 3-chloropropyl- e-capro- Potassium EDMF CO trimethoxysilane lactam cyanate (300 ml) A. / N (CH3O)3Si-C3H6-NH-CO-N-(CH2)5 8 0.2 mol 3-chloropropyl- e-capro- Sodium DMF CO dimethoxymethyl- lactam cyanate (50 ml) A. / N silane (Choi-ch-NH-co-N - (CH2)5 CH3

TABLE 2 Product Characterization Analysis Product Summation Molecular Calculated: Ex. Amount Yield Formula Weight Found: C H N 2 15.4 g 87.3% C9H20N2O5Si 294,354 40.89% 7.63%, 10.60% t 40.93% 7.76%, 11.8% 3 209.7 g 96.3% C11H22N2O5Si 290.392 45.50%, 7.64% 9.65% X r 45.27% 8.7% 9.88% 4. 162.4 g 97.7% C14H23N2O5Si 332,474 50.58% 8.49% 8.43% 50.7% 9.03% 8.39% 5 182.8 g 97.6% C17H34N2O5Si 374,555 54.52% 9.5% 7.48% 54.56% 9.55% 7.54% 6 298.9 g 98.2% C12H24N2O5Si 304,419 4.7.35% 7.95% 9.20% 47.68% 8.23% 9.45% 7 304.5 g 95.6% C3H26N2O5Si 318,447 49.03% 8.23% 8.80% 48.54% 8.66% 8.43% 8 55.9 g 92.5% C13H26N2O4Si 302,448 47.66%, 8.00% 9.26% 47.95% 8.25% 9.12%

What is claimed is: 3. A compound according to claim 2 where R2 is 1. A N-silylpropyl-N'-acyl-urea of the formula: hydrogen. 4. A compound according to claim 2 where R2 is C1-C6 alkyl. 45 5. A compound according to claim 2 where A is: in which CH2-D X is 0, 1, or 2 / al-N R is C1-C6 alkyl, (2'-methoxy)ethyl or aryl, 50 N A is CO-(CH2).

Rl O 6. A compound according to claim 5 where D is -N-C-R2 -CH2-. 55 7. A compound according to claim 6 where y is 3. 8. A compound according to claim 1 where x is 0. where R is C1-C6 alkyl, R2 is hydrogen, C1-C6 9. A process for the production of a compound ac alkyl or cording to claim 1 comprising mixing in an aprotic, * A is polar organic solvent equimolar amounts of an alkali 60 cyanate, a 3-halopropyl silane of the formula: CH2 re-D / X-C3H6-Si(CH3)x(OR)3-x (IV) e-N N CO-(CH2) and a compound of the formula: 65 where y is 1, 2, or 3 and D is -CH2-, or >NR1. O (V) 2. - A compound according to claim 1 where R is R2-C-NH-R or C1-C6 alkyl, (2'-methoxy)ethyl or phenyl. 4,697,009 9 10 12. A process according to claim 11 wherein the -continued solvent is dimethylformamide. CH2-D (VI) 13. A process according to claim 10 wherein the / solvent is dimethylformamide. HN 14. A process for setting free the blocked isocyanate N function from a compound according to claim 1 com CO-(CH2) prising thermolyzing the compound in a vacuum and and X is Cl, Br or I, subsequently reacting them with distilling off the 3-isocyanatopropylsilane formed of the formula: each other at elevated temperature, after the end of the 10 reaction cooling the reaction mixture to room tempera OCN-C3H6-Si(CH3)(OR)3. (VII). ture filtering off the precipitated alkalihalide and distill 15. A process according to claim 14 including a sec ing off the solvent from the filtrate. ond vacuum distillation. 10. A process according to claim 9 wherein the reac 16. A process according to claim 14 comprising car tion is carried out at 100-140' C. 15 rying out the thermolysis in the presence of a catalytic 11. A process according to claim 10 wherein there is amount of dibutyltin dilaurate. employed e-caprolactam. k k k k k

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