FI58633B - FARING REQUIREMENTS FOR THE RECOVERY OF URETANERS WHICH ARE REFERRED TO - Google Patents

Description

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(32) (33) (31) Caught in a stole * —Begird priority 30.00-72 US A (US) 28I4872 (71) Atlantic Richfield Company, Arco Plaza, 515 S. Flower Street,

Los Angeles, California, USA (72) John G. Zajacek, Strafford, Pennsylvania, John Joseph McCoy, Media,

Pennsylvania, USA (US), Karl Emil Fuger, Allschvil, Switzerland-Schweiz (CH) (7 ^) Oy Kolster Ab (5l) Method for the preparation of urethanes and related amines - For the preparation of urethanes and related amines

The invention relates to a process for the preparation of urethanes (esters of carbamic acid) and the amines formed therewith by reacting an aliphatic or aromatic alcohol containing at least one hydroxyl group with carbon monoxide and an aliphatic or aromatic nitro compound.

Previously, the commercial need for urethanes was met, at least in part, by reacting an isocyanate with a hydroxyl-containing compound at elevated temperature. The price and toxicity problems of isocyanate starting compounds have led to the search for new methods for the commercial production of urethanes.

U.S. Patent Nos. 3,338,956 and 3,448,140, for example, suggest that an organic compound containing at least one hydroxyl group is reacted with carbon monoxide and a nitrogen compound at elevated pressure and temperature to produce urethanes under elevated pressure and temperature with a catalyst such as Cr, Mo, W, Mn, Fe In the presence of -, Co, Ni, Ru, Rh, Os and Ir. Although the processes described in these patents use inexpensive 2 S8633 nitrogen compounds as starting materials, various factors, such as relatively low product yields, long reaction times, and high pressure, have precluded the economics of these methods to obtain high purity urethanes on a commercial basis. Among the problems associated with these prior art methods is the fact that many of the proposed catalysts are expensive and difficult to separate from the desired urethane products. Unless the catalyst can be separated for reuse, catalyst waste generally tends to make the operating costs of the process unsustainably high for commercial purposes. In addition, the lack of catalyst separation causes metal contamination of urethane products.

It has now been found that an aliphatic or aromatic alcohol containing at least one hydroxyl group can be reacted with carbon monoxide and a nitro compound at elevated temperature and pressure in the presence of a catalyst comprising sulfur, selenium, sulfur compound, selenium compound or mixtures thereof to form urethane. The process for the preparation of urethanes is normally carried out in the presence of a base and may also take place in the presence of a solvent. In addition, it has been found that the presence of water, either in place of or in addition to the base, may result in an improvement in the yield of the desired urethane products.

For a process according to the invention for the preparation of urethanes and their amines formed by reacting an aliphatic or aromatic alcohol containing at least one hydroxyl group with carbon monoxide and an aliphatic or aromatic nitro compound at a temperature of 60-250 ° C and a pressure of 10-500 atmospheres, preferably up to 100 atmospheres in the presence of, is characterized in that the catalyst is selenium, sulfur, a selenium compound, a sulfur compound or a mixture thereof and that at least one of the water or base is present.

Compounds which contain a hydroxyl group and which are suitable for use in the process of this invention include monohydric or polyhydric alcohols containing primary, secondary or tertiary hydroxyl groups. Mixtures of these compounds can also be used. The alcohols may be aliphatic or aromatic and may have other substituents in addition to the hydroxyl groups, but the substituents should, except as described below, preferably be unreactive with carbon monoxide under the process conditions.

3,58633

In general, compounds containing a hydroxyl group correspond to either of the general formulas R (OH) n and R '(OH) n, wherein n is 1 or a large group and preferably 1-3, R is an optionally substituted aliphatic, cycloaliphatic or araliphatic group which preferably contains 1 to 20 carbon atoms, R 'is an aromatic group containing one or more benzene rings and preferably not more than 3 rings, which may be fused or joined by simple valence bonds, directly or via bridging groups, which may be, for example, oxygen, nitrogen or sulfur atoms or sulfoxide, sulfone, amine, amide or carbonyl groups, or alkylene groups in which, if desired, the carbon chain may be interrupted by, for example, oxygen or sulfur atoms, sulfoxide, sulfone or carbonyl groups, for example methylene, oxymethylene, dimethylenesulfone or dimethylene ketone groups.

The group R may be alkyl, cycloalkyl, alkylene, cycloalkylene or Aralyl and the main carbon chain may, if desired, be, for example, sulfoxide, sulfone, amine, amide, carbonyl or carboxyl groups of oxygen, nitrogen or sulfur atoms. interrupted by ester groups. The substituents in the main chain may be, for example, alkyl, alkoxy, aryl or aryloxy groups which normally contain less than 10 carbon atoms. Particularly preferred compounds of formula R (OH) are monohydric alcohols such as methyl, ethyl, n- and sec-propyl, iso-, n- and tert-butyl, amyl, hexyl, lauryl, cetyl, benzyl, chlorobenzyl and methoxybenzyl alcohols as well as diols such as ethylene glycol, diethylene glycol, propylene glycol and diprepylene glycol, triols such as glycerol, trimethylolpropane, polyethylene and remains un-sharpened. The etherifying group of such ether alcohols normally contains up to 10 carbon atoms and is preferably an alkyl, cycloalkyl or aralkyl group which may be substituted, for example a haloalkyl group. Particularly suitable compounds of formula R (OH) are lower alkanols. Preferred compounds are methanol, ethanol, N-propanol, isopropanol, butanol, sec-butanol, iso-butanol, ethylene glycol, glycerol and trimethylolpropane.

The benzene rings of phenol compounds of the general formula R '(OH) may have substituents, e.g. alkyl and alkoxy groups containing up to 10 carbon atoms, as well as halogen atoms. Suitable monovalent and polyvalent phenols include phenol, chlorophenol, methyl, ethyl, butyl and alkyl phenols, catechol, resorcinol, quinol, 4,4, -dihydroxydiphenylmethane, naphthols, chloronaphthols, methyl, ethyl, butyl and octyl naphthols, anthranols, chloroanthranols, methyl, ethyl, butyl and octyl anthranols, phenanthrols, chlorophenanthrols, methyl, ethyl, butyl and octyl phenanthrols, pyrogallol, phloroglucinol, hydroxyquinol and polyhydroxyphenol ethers, provided that at least one of the ethers of the polyhydroxyphenol is provided. The etherifying group of such ethers contains up to 10 carbon atoms and is preferably an alkyl, cycloalkyl or aralkyl group which may be substituted, for example a haloalkyl group. Among the above-mentioned aromatic compounds, naphthols, anthranols and phenanthrols are particularly preferred, and especially the phenol itself.

Nitro compounds useful in the process include mononitro compounds such as nitrobenzene, alkyl and alkoxy nitrobenzenes in which the alkyl group contains up to 10 carbon atoms, aryl and aryloxy nitrobenzenes in which the aryl group is phenyl, tolyl, xylyl, naphthyl, chlorophenyl, chlorophenyl or chloronaphthyl, chloronitrobenzenes, dinitro compounds such as dinitrobenzene such as ortho-, meta- and paranitrobenzenealkyl and alkoxydinitrobenzenes in which the alkyl group contains up to 10 carbon atoms, aryl and aryloxydinitrobenzenes in which the aryl group is chloridinitrobenzenes, tri-nitro compounds such as trinitrobenzene, alkyl and alkoxytri-nitrobenzenes, aryl and aryloxythrinitrobenzenes, the substituents being one of the foregoing, and chlorotrinitrobenzenes and also similarly substituted naphthalenyl, diphenyl, diphenyl, diphenyl monos of the anthracene and phenanthrene series poly-nitro derivatives. Substituted or unsubstituted aliphatic nitro compounds such as nitromethane, nitroethane, nitropropane, nitrobutane, 2,2-dimethylnitrobutane, 3-methylnitrobutane, nitrooctadecane, 3-nitropropene-1, phenylnitromethane , p-bromophenylnitromethane, p-nitrophenylnitromethane, p-methoxyphenylnitromethane, dinitroethane, dinitropropane, dinitrobutane, dinitrohexane and dinitrodecane can also be used. Of this group of nitro compounds, aromatic nitro compounds such as nitrobenzene, nitrotoluene, dinitrobenzene, dinitrotoluene, trinitrobenzene, 4,4'-dinitrodiphenylmethane, p-nitroanisole, p-nitrophenethole, o-nitrophenethol, 2,4-dinitro 4-dinitrophenethole, 3,5-dinitrobenzyl acetate, 1-chloro-2,4-dimethoxy-5-nitrobenzene, 1,4-dimethoxy-2-nitrobenzene, p-nitrophenyl nitromethane and tertiary aliphatic nitro compounds such as 2 -methyl-2-nitropropane are preferred. Aromatic nitro compounds, i.e. 2,4-, 2,5- and 2,6-dinitrotoluenes; meta- and para-dinitrobenzenes and 4,4'-dinitrodiphenylmethane are particularly preferred.

Catalysts useful in this invention include sulfur, selenium, 5,586,333 sulfur compounds, selenium compounds, and mixtures thereof. Other Group Via metals in the Periodic Table of the Elements, such as the tellurium metal, have been found to be less effective than the catalysts set forth in the examples that illustrate the process of this invention.

The selenium metal, preferably in powder form, has been found to be at least as good or better than most selenium compounds. Nevertheless, good yields have been obtained with compounds such as selenium dioxide, selenium trioxide and mixtures of oxides, selenium oxychloride, titanium diselenide and selenium disulfide. Sodium selenite, zinc selenite, zinc selenide, tungsten selenide, selenium sulfide, selenic acid, dimethylselenide, diethylselenide, diethylselenide, diphenylselenide and carbonylselenide can also be used. Polyselenides such as diethylpolyselenide and dibutyl polyselenide may also be used. However, conversions and yields may not be equivalent for all selenium compounds.

In addition to the somewhat better performance of the selenium metal, preferably in powder form, than many of the aforementioned selenium compounds, selenium tends to provide somewhat better yields than sulfur catalysts. Sulfur catalysts include sulfur itself, various inorganic sulfur compounds such as hydrogen sulfide, carbonyl sulfide, carbon disulfide, sodium sulfide, potassium sulfide, sulfur dichloride, and organic sulfur compounds such as polysulfide, mercaptans, and thioethers having carbon atoms: i.e., diethyl polysulfide, dioctyl polysulfide, methyl mercaptan, ethyl mercaptan, cetyl mercaptans and the like can be used.

The above catalyst material may be self-supporting or precipitated in an inert support or support to disintegrate the catalyst to increase its effective surface area. Alumina, silicic acid, carbon barium sulfate, calcium carbonate, asbestos, bentonite, diatomaceous earth, expanded clay, organic ion exchange resins, and the like are useful carriers for this purpose. A specific example of a catalyst in a support is an ion exchange resin containing selenium as a cation and a sulfonic or carboxylic acid group as the anionic portion of the resin, such as a selenium-containing sulfonated macroporous, styrene-divinylbenzene resin. Selenium- or sulfur-containing molecular sieves can also be used, as well as selenium-sulfur complexes with the ligand.

Base and / or water must also be added to the reaction. Metal salts of both organic bases and carboxylic acids have been found to be effective. Suitable organic bases for the reaction include amines such as triethylamine, pyridine, quinoline, Ν, Ν-dimethylaniline, diethylamine, tertiary butylaramine, 1,4-diazobicyclo [2.2.2] octane, polyethylene polyamines such as N, N, Ν '»N'-tetramethylethylenediamine, tetramethyleneamine, ethylenediamine and the like. Thus, aliphatic, aliphatic-aromatic and aromatic heterocyclic amines can be used in the reaction. In addition, amines may form part of a polymer, such as in polyvinylpyridine. Compounds which are normally considered to be weak bases, such as metal salts of carboxylic acids, sulfonic acids and phosphoric acid, are preferred bases. Examples of such compounds and salts of other weak acids are lithium acetate, sodium acetate, potassium acetate, palladium acetate, ruthenium acetate, lithium salt of p-toluenesulfonic acid, lithium salt of methylsulfonic acid, lithium formate, lithium acid phosphate, lithium acid phosphate, boronic acid, boronic acid, may be added as preformed or may be prepared in the reaction mixture by the addition of appropriate amounts of the corresponding base and acid. There are no restrictions on the type of acid used, nor on the corresponding metal oxide or hydroxide used. Thus, aliphatic, cycloaliphatic and aromatic acids such as propionic, octanoic, cyclohexane, carboxylic, benzoic, oxalic, malonic acid and the like can be used. However, oxides or hydroxides of transition metal compounds tend to be more expensive than alkali and alkaline earth metal hydroxides.

From the prior art teachings that water should be completely absent if maximum yields are to be obtained, the preferred use of water in the reaction of this invention was unexpected. For example, the use of sodium acetate containing water of crystallization has been found to lead to a higher conversion of the nitrogen compound than the use of anhydrous sodium acetate. On the contrary, the prior art teaches the use of absolutely anhydrous reactants. Since quite large catches have been obtained using water without a base, it is normally desirable to use both a base and water.

While the process of the invention can typically be efficiently carried out without a solvent, a solvent can also be used. Aromatic solvents such as benzene, toluene, xylene; nitrile solvents such as acetonitrile and benzonitrile; amide-type solvents such as Ν, Ν-dimethylformamide and Ν, Ν-dimethylacetamide; aliphatic, alicyclic or aromatic sulfoxide and sulfone solvents such as dimethyl sulfoxide; aliphatic halogenated hydrocarbons such as 1,1,2-trichloro-1,2,2-trifluoroethane and halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene and trichlorobenzene; ketones; obstruction 7 58633 thighs; and ether solvents such as tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane and the like can all be used as solvents. The ether compounds may, for example, be aliphatic, aromatic or heterocyclic and may also be either mono- or polyethers or combinations of these compounds. When an organic compound containing at least one hydroxyl group is a liquid under the reaction conditions, it can sometimes act as a solvent and is generally preferred.

At higher temperatures and pressures, the process of the invention may advantageously take place in an inert diluent. Preferred inert diluents are those in which non-gaseous reactants are soluble, including a few of the solvents listed above. Suitable inert diluents include aliphatic or aromatic hydrocarbons such as n-pentane or toluene, ethers, ketones and esters.

The process is preferably carried out in the presence of at least molar amounts of hydroxyl-containing compound, carbon monoxide and organic nitrogen compound. Preferably, however, a molar excess of hydroxyl-containing compound or nitro compound, or both, is present.

The molar ratio of nitro compound to catalyst can vary over a wide range, i.e. from 5: 1 to 2000: 1, however, the somewhat more preferred molar ratio of nitrogen compound to catalyst is between 10: 1 and 1000: 1. It is to be understood that the term "mole" of a catalyst refers to the elemental selenium or sulfur and not to a compound if the catalyst is a compound. Likewise, a nitro compound refers to an active nitrogen-containing group, wherein if the nitro compound is a dinitro compound, e.g., dinitrotoluene, the molar number would be half, i.e., the equivalent ratio.

Similarly, with respect to the amount of base used, the molar ratio (calculated from equivalent nitrogen-containing groups in the nitro compound) may vary from 50: 1 to 1:10 as the ratio of nitrogen compound to base. Although water can be omitted altogether and the reaction can take place only in the presence of organic bases, if water is used, it is preferable to use an amount calculated on the weight of the catalyst. Thus, the molar ratio of water to catalyst, i.e., Se or S, may range from as little as 0.5: 1 to as much as 1000: 1 or more, but the preferred range is 1: 1 to 200: 1. In addition, it has been found that at reaction temperatures above 175 ° C, 8,58633 water can be used in the absence of base alone, although at temperatures below 175 ° C the base is used to obtain good yields of the desired products and it is generally preferred to use small amounts of water with base. Such water can be prepared in situ, for example, by using equal molar amounts of a base such as potassium hydroxide and an acid such as acetic acid to give equimolar amounts of the weakly basic compound, potassium acetate, and water. In general, it is preferable to use an organic base such as pyridine or triethylamine as the required additional amount of base.

It has also been found that although urethanes are generally the predominant product of the reaction of this invention, certain by-products are also obtained. The main by-products are amines and under certain reaction conditions they can become the predominant product. Reaction conditions that promote increased amine formation include the use of a sulfur catalyst and / or the use of larger amounts of water. It appears that sulfur catalysts are somewhat more advantageous for amine production than selenium catalysts, and in some cases somewhat higher amounts of water also promote amine formation.

However, the main object of the present invention is to prepare urethanes, as the preparation of amines would generally not be economically advantageous compared to commercially used alternatives. Nevertheless, several examples are given below in which nitrobenzene is converted to aniline and in which dinitrotoluene is converted to the corresponding mononitromonoamine compounds.

The order in which the reactants are mixed is usually not critical and may be varied within the limits of the equipment employed. A simple procedure is to place the nitro compound, an alcohol, catalyst, base and / or water containing at least one hydroxyl group in a reaction vessel, add an appropriate amount of carbon monoxide and then heat the mixture to achieve the desired reaction. A suitable pressure vessel, such as an autoclave, preferably equipped with heating devices and stirring devices, such as a stirrer or an external rocking mechanism, is used for the reaction.

In general, the amount of carbon monoxide in the free space of the reaction vessel is sufficient to maintain the desired pressure and to provide a reactant for the process. As the reaction progresses, additional carbon monoxide can be fed to the reaction vessel either intermittently or continuously. Although larger or smaller amounts of carbon monoxide may be used, if desired, a total amount of carbon monoxide of 9,53633 is added during the reaction, generally from about 3 to about 50 moles and preferably from about 8 to about 15 moles of carbon monoxide per non-cyclic group to which the nitrogen atom of the nitro compound is directly attached. to a single carbon atom and is also linked by a double bond to an oxygen or another nitrogen atom. The highest carbon monoxide requirements are usually associated with a process in which carbon monoxide is added continuously, but appropriate recovery of carbon monoxide-containing gas streams greatly reduces overall carbon monoxide consumption.

The reaction temperature is generally maintained between 60 and 250 ° C, and preferably between 100 and 200 ° C. These temperatures allow the appropriate reaction rate to be reached while avoiding undesired side reactions. It is to be understood, however, that any elevated temperatures below the temperatures at which the starting materials or products decompose may be used. The reaction is carried out, as described above, at elevated pressures, which are normally 10 to 500 atm. Preferably, however, only moderate carbon monoxide pressures between 10 and 100 atm are used. and the reaction is suitably carried out at temperatures below 200 ° C in this pressure range. Thus, the process of this invention can be advantageously used at lower temperatures and pressures than those generally considered necessary in connection with the use of other catalyst materials hitherto proposed for the conversion of hydroxy compounds and nitro materials into urethane products.

While this reaction of the invention is normally carried out in batches, the reaction may, if desired, be carried out in a semi-continuous or even continuous manner. Catalysts of the ion exchange type, for example, are particularly suitable for continuous reactions. The reaction time depends on the nature of the reactants, the temperature, the pressure and the type of catalyst used, as well as the type of equipment used. Normally the reaction time is less than 180 minutes and in general the efficiency of the catalysts of this invention makes it possible to complete the reaction in a time between 10 and 75 minutes.

When the reaction is complete, the temperature of the reaction mixture can be lowered to ambient temperature and the pressure can be released. The reaction mixture is then treated by conventional methods including filtration, distillation or other suitable separation methods to separate the urethane from the unreacted starting material, solvent, by-product, catalyst, etc.

The urethane products obtained by the invention contain one or more 10,86633 urethane groups and may be monomeric or polymeric in nature. Thus, the process of the invention can be used to prepare mono-urethanes from mononitro compounds and monohydroxy compounds, and can be used to prepare polyurethanes from polynitro compounds as well as monofunctional hydroxy compounds. The resulting urethane products, especially those urethanes which do not contain more than three urethane groups per molecule, can be converted to the corresponding isocyanates by suitable methods, such as thermal and catalyst methods.

As pointed out above, amines can also be prepared by the process of this invention and, for example, monoamines are prepared from mononitro compounds. In general, as stated, monourethanes are the predominant product, but it is also possible, as the examples show, to produce equal or even predominant amounts of amines. For example, in the case of dinitro compounds, amine products are generally a monoamine mononitro compound, i.e. only one of the nitro groups is reduced to an amine.

In addition, polyurethanes can be obtained from the interaction of polynitro compounds with polyols and carbon monoxide. Thus, direct polyurethanes useful, for example, as fibers or elastomers can be obtained directly from diols, dinitro compounds and carbon monoxide or hydroxynitro compounds and carbon monoxide, while crosslinked polyurethanes useful as flexible or rigid plastics can be obtained from flexible or rigid plastics. , diols or mixtures of polyols and carbon monoxides.

The invention is further illustrated by the following examples. The reactions shown in these examples have all taken place in 316 stainless steel vibrating autoclaves. However, it is to be understood that less expensive forms of stainless steel may be used and that, if desired, equivalent reaction vessels, such as glass lined vessels, may be used. The conversions and yields given in the examples were determined by gas chromatographic analyzes and analytical liquid chromatography.

Example I

10 ml of nitrobenzene and 15 ml of methanol were placed in a 110 ml 2 autoclave and kept under an initial carbon monoxide manometer pressure of 183 kg / cm 2. The autoclave also contained 1.6 g of selenium metal and 1.6 ml of pyridine. After 45 minutes at a reaction vessel temperature of 58633 at 200-225 ° C, the conversion of nitrobenzene was 98% and the yield of the resulting urethane product (methyl N-phenylcarbamate) was 88%.

When the same process was repeated, except that the reactants were kept under the described conditions for 3 hours, decomposition occurred and the maximum yield of urethane product obtained was only 53%.

Example II

10 ml of nitrobenzene and 15 ml of methanol were placed in a 110 ml autoclave and maintained at a temperature between about 200 and about 225 ° C at an initial pressure of 190 kg / cm 2 of carbon monoxide. The autoclave also contained 1.6 g of selenium metal and 1 g of triethylamine. After 45 minutes, the conversion of nitrobenzene was 72% and the yield of urethane product was 74%.

Example III

10 ml of nitrobenzene and 15 ml of methanol were placed in a 110 ml autoclave and maintained there at a temperature between 200-225 ° C and an initial pressure of 2,183 kg / cm of carbon monoxide in the presence of 0.5 g of selenium metal and 1 g of sodium acetate trihydrate. After 45 minutes, 94% nitrobenzene conversion had occurred and the urethane product yield was 68%.

When the procedure of Example III was repeated at a reaction temperature of 180 ° C and the reactants were kept under otherwise similar conditions for 90 minutes, the conversion of nitrobenzene dropped to only 23%. However, the yield of the urethane product was 68%.

Example IV

10 ml of nitrobenzene and 15 ml of methanol were placed in a 110 ml autoclave and maintained at 170 ° C under an initial pressure of 183 / cin carbon monoxide in the presence of 1.5 g of selenium metal and 16 ml of pyridine. After 60 minutes, the conversion of nitrobenzene was 22% while the yield of urethane product was 50%.

Similar conversions are obtained when nitrocyclohexane and ethylene glycol are reacted with carbon monoxide under the conditions defined in Example IV.

Example V

10 ml of nitrobenzene and 15 ml of ethanol were placed in a 110 ml autoclave and maintained there at a reaction temperature of 200-225 ° C and an initial pressure of 2,183 kg / cm of carbon monoxide with 0.5 g of selenium metal and 1.6 ml of in the presence of pyridine. After 60 minutes of conversion, the nitrobenzene was 10% and the yield of the urethane product was 52%.

12,58633

Similar conversions are obtained by reacting dinitrosotoluene and resorcinol with carbon monoxide under the conditions defined in Example V.

Example VI

10 ml of nitrobenzene and 10 ml of methanol were placed in a 110 ml autoclave and maintained at 200-225 ° C under an initial pressure of 193 / cm 2 of carbon monoxide in the presence of 2.2 g of selenium dioxide and 1.6 ml of pyridine. After 180 minutes, the conversion of nitrobenzene was 53% and the yield of urethane product was 63%.

Example VII

10 ml of nitrobenzene and 15 ml of methanol were placed in a 110 ml autoclave and maintained at 200-225 ° C at an initial pressure of 190 kg / cm of carbon monoxide in the presence of 3.3 g of selenium oxychloride and 1.6 ml of pyridine. After 60 minutes, the conversion of nitrobenzene was 100% and the yield of the urethane product was 42%.

Example VIII

10 ml of nitrobenzene and 65 ml of methanol were reacted with carbon monoxide in a 110 ml vibrating autoclave at 200 ° C at an initial pressure of 21 kg / cm of carbon monoxide. The autoclave contained 1 g of selenium metal as catalyst together with 1.5 ml of pyridine. After a reaction time of 180 minutes, the nitrobenzene conversion was 52% and the yield of the urethane product was 76%.

Example IX

5 ml of nitrobenzene and 65 ml of methanol were placed in a 110 ml autoclave and kept under an initial pressure of 21 kg / cm of carbon monoxide at 200 ° C. 0.5 g of selenium metal and 1.5 ml of pyridine were used for the reaction. After 150 minutes, the conversion of nitrobenzene was 30% and the yield of the urethane product was 67%.

Example X

5 ml of nitrobenzene and 65 ml of methanol were placed in a 110 ml vibrating autoclave and kept at 200 ° C under an initial pressure of 21 kg / cm 2 of carbon monoxide. The reaction vessel also contained 0.5 g of selenium metal and 1.6 ml of pyridine along with 1 g of sodium acetate trihydrate. After 75 minutes, the nitrobenzene conversion was 59% and the yield of urethane product was 50%.

When a similar process of Example X was repeated at an initial pressure of 35 kg / cm carbon monoxide, the nitrobenzene conversion after 60 minutes was 80% and the yield of the urethane product was 67%.

2 2 1 3 58633

Example XI

2.5 ml of nitrobenzene and 65 ml of methanol were placed in a 110 ml vibrating autoclave and kept under an initial pressure of 35 kg / cm of carbon monoxide at 200 ° C. 0.25 g of selenium metal and 1 g of sodium acetate trihydrate were used for the reaction. After a reaction time of 10 minutes, the nitrobenzene conversion was 95% and the yield of the urethane product was 78%.

Example XII

5 ml of nitrobenzene and 30 ml of methanol were placed in a 110 ml vibrating autoclave and maintained at an initial pressure of 56 kg / cm of carbon monoxide at 200 ° C. In addition, the autoclave contained 0.5 g of selenium metal, 35 ml of tetrahydrofuran and 1 g of sodium acetate trihydrate. After a reaction time of 10 minutes, the nitrobenzene conversion was 64% and the yield of the urethane product was 74%.

When the reaction of Example XII was repeated at 170 ° C, a 72% nitrobenzene conversion and a 70% yield of urethane product were obtained after 60 minutes.

Example XIII

5 ml of nitrobenzene, 30 ml of methanol and 35 ml of tetrahydrofuran were placed in a 110 ml vibrating autoclave and maintained at a temperature of 200 ° C and an initial pressure of 56 kg / cm of carbon monoxide. In addition, 0.5 g of selenium metal and 2 g of sodium acetate trihydrate were present in the autoclave. After 10 minutes, the nitrobenzene conversion was 70% and the yield of urethane product was 53%.

When the reaction of Example XIII was repeated, except that it was performed at 170 ° C instead of 200 ° C, the nitrobenzene conversion was 100% and the yield of urethane product was 74%.

Example XIV

5 ml of nitrobenzene and 30 ml of methanol were placed in a 110 2 ml vibrating autoclave maintained at an initial pressure of 56 kg / cm of carbon monoxide at 170 ° C. In addition, 35 ml of tetrahydrofuran was involved in the autoclave reaction. 0.008 moles of lithium acetate monohydrate and 0.5 g of selenium metal. After a reaction time of 10 minutes, a 94% nitrobenzene conversion and a 68% yield of urethane product were obtained.

By repeating Example XIV, except that the autoclave is maintained at 160 ° C instead of 170 ° C, 100% nitrobenzene conversion and 83% yield of urethane product were obtained after 60 minutes.

14 58633

When the procedure of Example XIV was repeated, except that it was performed at 150 ° C instead of 170 ° C, the nitrobenzene conversion was 87% and the urethane yield was 85% after 60 minutes.

Finally, when the procedure of Example XIV was repeated using 130 ° C instead of 170 ° C, the nitrobenzene conversion was 89% and the yield of urethane product was 71% after 140 minutes. Example XV

5 ml of nitrobenzene and 30 ml of methanol were placed in a 110 ml vibrating autoclave together with 35 ml of tetrahydrofuran, 0.1 g of titanium disulfide and 0.008 mol of lithium acetate monohydrate. The autoclave was maintained at 150 ° C under an initial pressure of 56 kg / cm carbon monoxide. After 60 minutes, a 96% nitrobenzene conversion and an 88% yield of urethane product were obtained.

When the procedure of Example XV was repeated except that lithium acetate monohydrate was omitted, the conversion of nitrobenzene to 0% was obtained.

Example XVI

0.29 g of lithium hydroxide, 0.72 g of acetic acid, 10 ml of nitrobenzene, 15 ml of methanol, 15 ml of dioxane and 0.5 g of selenium disulfide were placed in a 110 ml autoclave. The autoclave was maintained at 200 ° C 2

45 minutes at an initial pressure of 183 kg / cm of carbon monoxide. After 45 minutes, the nitrobenzene conversion was 100% and the urethane yield 96%. Example XVII

0.29 g of lithium hydroxide, 0.72 g of acetic acid, 0.5 g of sulfur, 5 ml of nitrobenzene, 30 ml of methanol and 35 ml of tetrahydrofuran 2 were placed in a 300 ml autoclave kept at an initial pressure of 56 kg / cm of carbon monoxide and 170 ° C for 75 minutes. After time, the nitrobenzene conversion was 100% and the yield of the urethane product (methyl N-phenylcarbamate) was 75%.

Example XVIII

10 ml of nitrobenzene, 65 ml of methanol, 1 g of sulfur, 1.6 ml of pyridine and 1 g of sodium acetate trihydrate were placed in 300 ml of 2 autoclaves and kept under an initial pressure of 183 kg / cm of carbon monoxide at 200 ° C for 45 minutes. The nitrobenzene conversion obtained was 83%, with a yield of urethane product of 38%.

When the procedure of Example XVIII was repeated, except that 2 g of sulfur was used instead of 1 g, the nitrobenzene conversion was 94% and the yield of the urethane product was 33%.

15 58633

Example XIX

10 ml of nitrobenzene, 65 ml of methanol, 0.5 g of sulfur and 1 g of sodium acetate trihydrate were placed in a 300 ml autoclave 2 maintained at an initial pressure of 183 kg / cm of carbon monoxide and at a temperature of 200 ° C. After 45 minutes, the nitrobenzene conversion was 46% and the yield of urethane product was 32%.

Example XX

10 ml of nitrobenzene, 15 ml of methanol, 15 ml of dioxane, 0.29 g of lithium hydroxide, 0.72 g of acetic acid, 0.10 g of selenium metal and 0.30 g of sulfur were placed in a 110 ml autoclave kept in an 183 kg autoclave. / cm2 under an initial pressure of carbon monoxide and at a temperature of 200 ° C for 45 minutes. After the time, 75.2% conversion of nitrobenzene had taken place and the product yield of urethane was 82.5%.

Example XXI

0.29 g of lithium hydroxide, 0.72 g of acetic acid, 0.25 g of sulfur, 0.25 g of selenium metal, 10 ml of nitrobenzene, 15 ml of methanol and 15 ml of dioxane were placed in a 110 ml autoclave kept in an 183 kg autoclave. / cm2 as the initial pressure of carbon monoxide and at 200 ° C for 45 minutes. 98% nitrobenzene conversion and 88.4% yield of urethane product were obtained as determined by gas chromatographic analysis.

Example XXII

0.29 g of lithium hydroxide, 0.72 g of acetic acid, 0.5 g of selenium metal, 5 ml of nitrobenzene and 65 ml of methanol were placed in a 300 ml autoclave maintained at an initial pressure of 56 kg / cm of carbon monoxide and at 150 ° C: temperature for 60 minutes. The nitrobenzene conversion obtained was 100% with a yield of urethane product of 81.2%.

Example XXIII

The following experiments were performed in a 300 ml autoclave by placing the following substances in the autoclave together with base and / or water: 10 ml of nitrobenzene, 30 ml of methanol, 35 ml of 1,4-dioxane and 0.5 g of selenium metal.

The reactions were allowed to proceed at 200 ° C for 30 minutes at an initial pressure of 2,183 kg / cm carbon monoxide. The following table shows the base and / or water used in the reaction and the nitrobenzene conversion that took place: 16,58633

Base Nitrobenzene _conversion (%) _ 1 g sodium acetate trihydrate 100 1 g sodium acetate (molten) 8 1 g sodium acetate (molten) and 0.2 g water 100 0.48 g sodium hydroxide and 0.72 g acetic acid 91 1 g anhydrous potassium acetate 50 1 g anhydrous potassium acetate and 0.2 g water 100 no base no water 9 0.3 g water 64

Example XXIV

Reaction mixture with 10.9 g (0.06 mol) of 2,4-dinitrotoluene, 65 ml (1.11 mol) of ethyl alcohol, 0.56 g (0.01 mol) of potassium hydroxide, 0.60 g (0 .01 moles) of acetic acid and 0.5 g of selenium metal powder (0.006 moles) were placed in a reaction vessel, which was then pressurized with carbon monoxide. At a reaction temperature of 170 ° C, 100% conversion of dinitrotoluene was obtained in 15 minutes and the yield of diurethane was 72%. A similar second experiment performed at 150 ° C for 60 minutes gave 100% conversion of dinitrotoluene and 72% yield of diurethane.

Example XXV

A mixture of 10.9 g (0.06 mol) of 2,4-dinitrotoluene, 35 ml (0.6 mol) of ethyl alcohol, 30 ml (0.21 mol) of triethylamine and 0.5 g (0.006 mol) of selenium metal powder, placed in 2 reaction vessels and pressurized to 56 kg / cm with carbon monoxide. At 150 ° C, 100% conversion of dinitrotoluene to a diurethane yield of 73% was achieved in 60 minutes and a mono-urethane yield of 3% was obtained, i.e. 1 nitro group was not converted, thus giving a combined product yield of 76%.

Example XXVI

A mixture of 10.9 g (0.06 mol) of 2,4-dinitrotoluene, 35 ml (0.6 mol) of ethyl alcohol, 40 ml (0.37 mol) of pyridine, 0.56 g (0.01 mol) potassium hydroxide, 0.60 g (0.01 mol) of acetic acid and 0.05 g (0.0006 mol) of selenium metal powder were placed in 2 reaction tanks, which were then pressurized to 56 kg / cm with carbon monoxide. At 160 ° C over 60 minutes, 100% conversion of dinitrotoluene was obtained and the products were obtained from the two isomers of 1% nitroaminotoluene, 19% nitromonourethane and 71% diurethane 17,58633. The total yield or selectivity for urethane for this was 90%. In a similar experiment, 0.072 g (0.006 moles) of selenium dioxide was used as a catalyst for selenium metal powder amine and the reaction was allowed to proceed at 150 ° C for 50 minutes; 100% conversion of dinitro-toluene to product yield was obtained comprising 3% nitroamino-toluenes, 34% monourethanes and 56% diurethanes.

Example XXVII

A mixture of 10.9 g (0.06 mol) of 2,4-dinitrotoluene, 65 ml (1.11 mol) of ethyl alcohol, 1.12 g (0.02 mol) of potassium hydroxide, 1.2 g (0 .02 moles) of acetic acid and 0.05 g (0.0006 moles) of selenium metal powder were placed in a reaction vessel, which was then pressurized to 56 kg / cm with carbon monoxide. The reaction was carried out at 150 ° C for 20 minutes to give 100% conversion of dinitro-toluene. The product yield was 70% by weight of monourethane and 19% by weight of diurethane, giving an overall selectivity of 89% for urethanes. In a similar experiment using 1.68 g (0.03 moles) of potassium hydroxide and 1.80 g (0.03 moles) of acetic acid with the same other reactants, 100% conversion of dinitrotoluene was obtained in 50 minutes at 150 ° C. product yield comprising 3% nitroaminotoluenes, 50% monourethanes, 44% diurethanes, giving 94% selectivity for urethanes.

Example XXVIII

A mixture of 10.9 g (0.06 mol) of 2,4-dinitrotoluene, 35 ml (0.6 mol) of ethyl alcohol, 15 ml (0.19 mol) of pyridine, 15 ml (0.11 mol) of triethylamine and 0, 05 g of selenium metal powder (0.0006 mol) was placed in a reaction vessel, which was then brought to a pressure of 56 kg / cm 2 with carbon monoxide. At a reaction temperature of 160 ° C, 100% conversion of dinitrotoluene to product yield was obtained in 60 minutes, comprising 8% nitroaminotoluenes, 63% monourethanes and 15% diurethanes, i.e. a total of 78% urethanes. When 0.01 g of water was added to this same reaction mixture and the reaction was allowed to proceed at 160 ° C for 40 minutes to give a 98% conversion of dinitrotoluene to the product crop comprising 14% nitroaminotoluenes, 75% monourethanes and 18% diurethanes, giving a total of 93% urethanes.

Example XXIX

To demonstrate continuous urethane synthesis, a unit was built on a pilot plant scale where liquid reactants were pumped together with a stoichiometric excess of carbon monoxide 2 into a stirred reaction tank operated at 70 kg / cm.

18 58633

In typical use, the liquid mixture comprised 10% by weight of commercially available dinitrotoluene (80% of 2,4-dinitrotoluene and 20% of 2,6-dinitrotoluene), 87% by weight of commercial ethanol (denatured ethanol containing 2% of benzene), 1% by weight of % acetic acid, 1% by weight of potassium hydroxide and 1% by weight of selenium dioxide as soluble catalyst. From the results obtained under different conditions, it was found for this system that the optimum operating conditions were a temperature of 177 ° C 2 for 0.5 hours at a pressure level of 70 kg / cm. Under these conditions, 100% conversion of dinitrotoluene was obtained with a selectivity for di-urethanes of 90-95%. At temperatures below 177 ° C, e.g. 163 ° C, the conversion becomes a function of the residence time, so that shortening the residence time from 1 hour to 1/2 hour and 1/4 hour at 163 ° C reduces the conversion from 100% to 90%, respectively. and 76%. In addition, operating below 177 ° C and 1/2 hour gives lower diurethane catches and higher monourethane catches. When working at temperatures above 177 ° C and for more than 1/2 hour, lower yields of diurethanes are usually obtained together with decomposed products. Under optimal conditions, the conversion of dinitrotoluene is fast even at low catalyst concentrations, for example 90% conversion is achieved by adding only 0.07% by weight of selenium catalyst to the feed.

These continuous uses demonstrate the excellent commercial feasibility of this method.

The following examples are given to illustrate the preparation of amines. These are purely descriptive and selected from a large number of experiments in which amines were prepared as a single product. The same type of equipment and procedures used in the above batch examples were also used in these experiments.

Example XXX

A 300 ml 316 stainless steel vibrating autoclave was charged with 12.0 g (0.098 moles) of nitrobenzene, 79 g (2.46 moles) of methanol, 2.0 g (0.062 moles) of sulfur (as a powder), 1.0 g ( 0.0073 moles) of sodium acetate trihydrate and 1.6 g (0.02 2 moles) of pyridine. The autoclave was brought to an initial pressure of 56 kg / cm with carbon monoxide and the reaction mixture was kept at 220 ° C for 2 hours.

After reduction to ambient temperatures and pressure, it was found that the conversion of nitrobenzene was 77.4 mol% and that the yield of aniline was 56.6 mol% and the yield of urethane was 6.5 mol%. Example XXXI

At the same time, 10 ml (0.098 mol) of 19,58633 nitrobenzene, 100 ml of methyl alcohol, 1 g of sodium acetate and 1 g of powdered sulfur were placed in a 300 ml reaction vessel. The reaction vessel was pressurized with carbon monoxide 2 to 35 kg / cm and the reaction was allowed to proceed for 10 minutes at 220 ° C. A conversion of 35.5 mol% to nitrobenzene was obtained with a selectivity of 30.4 mol%, i.e. by yield, to aniline and a yield of 39.3% was obtained from urethane.

Example XXXII

A mixture of 10.9 g of 2,4-dinitrotoluene, 100 ml of ethyl alcohol, 1.28 g of potassium acetate monohydrate and 0.5 g of sulfur

The mixture was placed in a 300 ml reaction vessel and raised to 35 kg / cm with carbon monoxide. The reaction was carried out at 200 ° C for 1 hour to give a 44.8 mol% conversion of 2,4-dinitrotoluene. The percentage selectivity based on converted dinitrotoluene was 40.2% for the two monourethane isomers with one nitro group unchanged, 41% for the nitroamino-toluene isomers and less than about 1.5% for the diurethanes. Example XXXIII

A reaction mixture of 10.9 g of 2,4-dinitrotoluene, 35 ml of ethyl alcohol, 30 ml of pyridine, 1 g of water and 0.012 g of selenium metal powder was placed in a reaction vessel, which was then pressurized to 25 kg / cm 2 with carbon monoxide. The reaction was carried out at 150 ° C for 90 minutes to give an 83% conversion of dinitrotoluene. Mononitrourethanes yielded 14% with traces of diurethanes and nitroaminotoluenes yielded 78%. The second experiment was performed under the same conditions as the previous one, except that 0.4 g of water and 0.015 g of selenium powder were used. A 90% conversion of dinitrotoluene was obtained, as well as a 55% yield of monourethane with traces of diurethane and a 46% yield of nitroaminotoluene.

From the foregoing, it can be seen that the present invention is well adapted to give all the results and objects set forth above, together with other advantages which are obvious and which are inherent in the method. The process is capable of commercially producing urethane products with high yields as well as amine by-products at relatively low working temperatures and pressures and using relatively short reaction times.