DE1643661A1 - Process for the preparation of trialkoxymethylureas - Google Patents

Description

Process for the preparation of trialkoxymethylureas Subject This invention is a process for making trialkoxymethyl ureas by reacting urea with formaldehyde and alcohols.

It is from the reports of the German Chemical Society, volume 41, page 24 (1908) known that urea can be mixed with formaldehyde to form monomethylol and Dimethylolurea and then these compounds with an alcohol in the presence convert an acid to the corresponding monoalkoxy or dialkoxymethylureas can. The addition of one or two moles of formaldehyde to urea to form the monomethylol or dimethylolurea is carried out in the presence of basic catalysts, since in the presence of acids a polycondensation to polymethylene ureas is very easy entry. Trimethylolurea and tetramethylolurea were made this way not made. When reacting urea with formaldehyde in alkaline Medium and a subsequent reaction of the reaction mixture with alcohol in The presence of catalytic amounts of acid is found in another in Bulletin Chemical Society of Japan Volume 11, page 248 (1956) and in the French patent 1 250 183 described procedure 4- Oxo-3,5-dialkoxymethyl-tetrahydro-1,3,5-oxadiaxine.

It has been found that trialkoxymethylureas of the general formula In which the individual radicals R1 are the same or different and each represent an aliphatic radical, advantageously obtained when ureas of the general formula in which one radical R2 denotes hydrogen and the other two radicals R2 can be identical or different and each denotes hydrogen, the radical -CH2-Ct: I or the radical -CHp-OR1, in which R has the aforementioned formula, with at least 5 mol Formaldehyde and with at least 3 moles of an alcohol of the general formula R1OH III, in which R1 has the aforementioned meaning, at a pH between 5 and 7 and a temperature between 50 and 1200C. The reaction can also be carried out in a first stage in the absence of the alcohol and the reaction product formed can be reacted with the alcohol in a second stage in a known manner.

In the case of using methanol and urea or methylol or dimethylol urea, the reaction can be represented by the following formulas: The process according to the invention provides, starting from readily available starting materials, trialkoxymethylureas in a simple way and in good yield. With regard to the aforementioned publications, these results are surprising.

The starting materials used are ureas of the general formula II Preferred starting materials II and correspondingly preferred end products I are those in whose formulas one radical R2 denotes hydrogen and the other two radicals R can be identical or different and each denote hydrogen, the radical —CH2 — OH or the radical —CH2-OR1. In the preferred starting materials and end products, the individual radicals R1 are identical or different and each denotes an alkyl radical with 1 to 12, in particular 1 to 4 carbon atoms, or the radical - (CH,) n-OR3J in which R5 is an alkyl radical with 1 to 12, in particular denotes 1 to 4 carbon atoms and n is 2 or 3. The aforementioned alkyl radicals can be straight-chain or branched.

So z. B. used the following ureas as starting materials II are: urea, mono- or dimethylolurea; Methoxy, butoxy, pentoxy, Isopropoxymethyl urea and the corresponding dialkoxymethyl ureas; N-methoxymethyl-N-propoxymethylurea, N-ethoxy-methyl-Nt-propoxymethylurea analogous methyl, propyl, butyl glycol ethers corresponding mono- and dimethylolureas and corresponding propylene glycol dieters.

Another starting material for the process is formaldehyde, which is useful is used as an aqueous solution, optionally stabilized with alcohol. Likewise it can also be used in the form of paraformaldehyde. In the implementation at least 3 moles of formaldehyde are used per mole of urea. Preferably the Reaction with 4 to 5 moles of formaldehyde per mole of unsubstituted urea, with 3 to 4 moles of formaldehyde in the case of monomethylolated and 5 moles of formaldehyde in the case of dimethylolated Ureas carried out.

Corresponding molar ratios apply mutatis mutandis to the implementation of Mono- and dialkoxymethyl ureas.

Other starting materials for the process are alcohols in general Formula III ROH III.

They are at least in an amount of 3 moles per mole of urea, in but usually used in a higher, preferably 5 to 20-fold excess. Preferred Starting materials III are those in whose formula R1 the. aforementioned, preferred Has meaning. So Korinen z. B. used the following alcohols as starting materials III be: methanol, ethanol, propanol, isopropanol, butanol, methylglycol, propylglycol, Methyl propylene glycol, butyl propylene glycol. s Implementation is at a PH value between 3 and 7, preferably @ white @ e @ and 6, carried out. The corresponding pH value becomes sweeping by adding inorganic or organic, under the reaction conditions non-oxidizing acids. @@ lchen acids are z. B. alkanecarboxylic acids such as acetic acid and preferably formic acid; Dicarboxylic acids such as oxalic acid; Sulfonic acids, such as benzene or p-toluenesulfonic acid; Sulfuric acid or preferably hydrogen chloride, e.g. in the form of hydrochloric acid. The proportion of formic acid is often enough, which is generally orh in aqueous maldehyde solution.

The reaction is carried out at a temperature between 50 and 120 ° C, preferably between 70 and 1000C, without pressure or under pressure, continuously or discontinuously carried out. In general, the alcohol used is also the solvent medium for the reaction mixture, it can optionally also solvents inert under the reaction conditions, such as Water or dioxane can also be used.

The reaction can be carried out as follows: A mixture of starting material II, formaldehyde, an alcohol IEI and acid is used for 1 to 8 hours, generally for 3 to 5 hours be the aforementioned pH value and reaction temperature given above heated. The reaction mixture is then cooled and, if necessary, with N-atron lye neutralized. Then the end product is made of the mixture in usual Way, e.g. B. by fractional distillation or filtration and recrystallization of the filter material, separated.

The reaction can also be carried out in two stages by using one first stage works in the aforementioned manner without the addition of alcohol 11 and so reaction product formed in a second stage with alcohol in a known manner implements. For example, you can work as follows: A mixture of starting material II, formaldehyde and acid is for 1 to 5 hours at the above-mentioned pH @@@ @ action temperature heated. Then w @ rd the reaction mixture @@@ g @ dam @ rt, the residue is with alcohol @@@ and acid added and the resulting mixture to the aforementioned reaction temperature, @. B to a temperature between 50 and 8r0c, or optionally between 50 and 50 ° C, and at a pH value between 7 and 7, preferably between pH 2 and 3, heated for 1 hour. The mixture is now cooled with sodium hydroxide solution neutralized and worked on in the named way.

The compounds which can be prepared by the process of the invention are ind Paint raw materials and valuable intermediate products for the production of aminoplasts and varnishes. So you can use them in a 30 to 50% alcoholic solution with acid salts, e.g.

Ammonium chloride, impregnate wooden surfaces, dry at 110 to 160 ° C and thus achieve scratchy wood polishes.

The parts mentioned in the examples are parts by weight.

Example 1 60 parts of urea are mixed with 335 parts in a stirred apparatus Parts of 36% aqueous formaldehyde are added and the mixture is heated to 95 ° C. for 3 hours warmed up. The pH of the reaction solution is around PH 6.

The reaction solution is then concentrated under reduced pressure steamed. The syrupy residue is with 300 parts of methanol and 5 Parts of concentrated hydrochloric acid are added and the resulting mixture is 1 hour heated to 50 ° C. with stirring. After neutralizing the mixture with dilute The excess methanol and the resulting water of reaction are sodium hydroxide solution removed by distillation under reduced pressure. The syrupy reaction mixture obtained is subjected to a fractional high vacuum distillation. The faction that passes at 0.2 torr in the boiling range between 70 and 1000C, is collected separately. In this boiling range, 102 parts of trimethoxymethylurea are used as a crude product obtain. This corresponds to a yield of 55% in theory. With another The trimethoxymethylurea becomes analytically pure in high vacuum distillation obtain.

Boiling point at 0.2 torr 97 to 980C.

Analysis C7H1604N2 (192) calcd: C 43.8 5 H 8.3% 0 33.5% N 14.6 % CH2O 46.9% CH30 48.3% found: C 43.8 5 H 8.5% 0 32.8% N 15.0% CH2O 47.7 % CH30 48.7% Example 2 A mixture of 120 parts of urea and 210 parts of paraformaldehyde 500 parts of ethanol are added, the pH is adjusted to 6 with formic acid and heated in a stirring apparatus for 5 hours to 80 to 85 ° C with stirring. After evaporation of the excess alcohol and the water of reaction under reduced pressure the syrupy residue obtained is distilled in a high vacuum. The main faction that Distilled at 0,) Torr between 125 and 160 ° C, is another fractionated Subjected to high vacuum distillation.

140 parts of triethoxymethylurea are obtained (corresponds to 32 of the theory). Boiling point at 0.7 Torr 120 to 123 ° C.

Analysis: C10H22O4N2 (222) calcd: C 51.3% H 9.4% N 12.0% CH2O 40.5% found: C 50.7% H 9.3% N 12.1% CH2O 40.3%.

Example 3 60 parts of urea are mixed with 555 in a stirred apparatus Parts of 36% formaldehyde are added and the mixture is heated to 95 ° C. for 3 hours with stirring. The reaction solution is then evaporated under reduced pressure. Of the 400 parts of butanol and 5 parts of oxalic acid are added to the syrupy residue Heated to 60 ° C. for 2 hours with stirring. After neutralizing the mixture with dilute Sodium hydroxide and filtration remove the excess butanol and the resulting The water of reaction was removed by distillation under reduced pressure. The syrupy one The residue is subjected to a fractionated high vacuum distillation. The parliamentary group which passes between 120 and 130 ° C at 0.2 Torr is collected separately and again subjected to a high vacuum distillation. 76 parts of tributoxymethylurea are obtained (corresponds to 24 of the theory). Boiling point at 0.2 torr 123 to 126 ° C Analysis: C16H34O4N2 (318) calcd: C 60.4, H 10.7 ffi, O 20.1%, N 8.8%, OH 2 O 28.5% found: C, 59.9 % H 10.6% 0 21.0% N 8.5% CH2O 28.0%.

Claims (3)

Claims 1. Process for the preparation of trialkoxymethylureas of the general formula in which the individual radicals R1 are identical or different and each represent an aliphatic radical, characterized in that ureas of the general formula in which one radical R2 denotes hydrogen and the two other radicals R2 can be identical or different and in each case denote hydrogen, the radical -CH2-OH or the radical -CH2-0R1 'in which R1 has the aforementioned meaning, with at least 3 moles of formaldehyde and with at least 3 moles of an alcohol of the general formula R1OH III, in which R1 has the aforementioned meaning, at a pH value between 3 and 7 and a temperature between 50 and 120 ° C. 2. The method according to claim 1, characterized in that the Implementation in a first stage in the absence of alcohol and the formed Reacts reaction product in a second stage with alcohol in a known manner. 3. Trialkoxymethylureas of the general formula in which the individual radicals Rt are identical or different and each represent an alkyl radical with 1 to 4 carbon atoms or the radical - (CH2) n-OR3, in which R3 denotes an alkyl radical with 1 to 4 carbon atoms and n is 2 or 5.