JPS5885852A - Condensation of n-phenylcarbamic acid ester - Google Patents

Abstract

PURPOSE:To prepare methylene-bis(4-phenylcarbamic acid ester) in high selectivity, by condensing an N-phenylcarbamic acid ester by the reaction with a methylating agent in the presence of a specific solid acid catalyst. CONSTITUTION:The N-phenylcarbamic acid ester of formula (R is alkyl, etc.; R' is H, alkyl, etc.; r is 0-4) is condensed to obtain methylene-bis(4-phenylcarbamic acid ester) by reacting the compound of formula with a methylating agent in the presence of a solid acid catalyst composed of at least one sulfonic acid (e.g. methanesulfonic acid, methanetrisulfonic acid, etc.) having at least two sulfonic acid groups per one molecule and a solid carrier (e.g. alumina, silica, etc.). Since the above catalyst has high selectivity of said bis compound and is a solid catalyst, the corrosion of the reaction apparatus can be reduced and the separation and recovery of the catalyst can be carried out easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention a relates to a method 1 for condensing N-phenylcarbamate esters via a methylene bond.

More specifically, the present invention relates to a method for obtaining a bis isomer with high selectivity when N-phenylcarpamic acid ester is reacted with a methylenating agent and condensed.

This methylene-bis-(-monophenylcarpamate ester) is used as a precursor of 4I, #'-diphenylmethane diisocyanate (so-called pure MDI), and also as a precursor of 4I, #'-diphenylmethane diisocyanate (so-called pure MDI). , polymethylene polyphenyl carno (mixture with mic acid ester is a so-called crude It is a substance useful as a precursor of MDI.These isocyanates are extremely important industrially as raw materials for polyurethane, and pure MDI in particular has been in demand in recent years as a raw material for polyurethane elastomers and coating materials for Spandeknu 1 artificial leather. Therefore, we have developed an industrially advantageous method for producing polymethylene polyphenylcarbamates containing large amounts of methylene bis-(4t-phenylcarno(minic acid ester)), which is the raw material. It is desired to do so.

Conventionally, as a method for producing methylene-bis-(derphenylcarhamic acid ester) using N-phenylcarbamic acid ester as a starting material.

A method of reacting formalin, paraformaldehyde, triochitin, etc. as a condensing agent in an aqueous medium with an ordinary liquid mineral acid such as hydrochloric acid, sulfuric acid, or phosphoric acid as a catalyst, or in an organic solvent with an organic sulfonic acid as a catalyst. Methods of reaction are known.

However, these methods produce large amounts of side reaction products of the target substance, nodelene bis-(4t-phenylcarbamate ester).

It has drawbacks such as low yield of the target product and time-consuming isolation of the target product, and is not industrially satisfactory.

For example, in the reaction in an aqueous solution using water as a medium, an N-(alkoxycarbonyl)phenylaminomethylphenyl compound formed by a reaction at the nitrogen of the N-phenylcarbamate ester, and this compound,
dimer of things.

N-benzyl compounds such as trimers are formed in significant amounts. Furthermore, in a condensation reaction using an organic sulfonic acid as a catalyst in an organic solvent medium, a considerable amount of polymethylene polypenylcarbamate containing three or more benzene rings is produced as a by-product.

In either method, the selectivity of the target is not very high.

In addition, the liquid acid catalyst used in these conventional methods is not easy to separate and recover, and the treatment of its waste acid is also troublesome as it involves pollution problems.In particular, the equipment is highly corroded, so the reaction equipment is made of different materials. It is extremely disadvantageous industrially because it is subject to severe restrictions.

Therefore, the present inventors have conducted intensive research on a method of condensing N-phenylcarbamate with a methylene bond, and as a result, the various drawbacks mentioned above have been solved by using it as a solid acid catalyst. Methylene-
It was discovered that a methylene compound rich in bis-(derphenylcarpamate ester) could be produced, and based on this finding C2, the present invention was completed.

That is, 1 the present invention provides N in the presence of a monolithic acid catalyst consisting of a complex composed of at least 7 types of sulfonic acids having at least one sulfonic acid group per 7 molecules and a solid support.
An object of the present invention is to provide a method for condensing N-phenylcarbamate, which comprises reacting phenylcarbamate with a methylenating agent.

The solid acid used as a catalyst in the present invention may be of any type as long as it is a complex composed of a sulfonic acid having at least two sulfonic acid groups per seven molecules and a solid support. Such a complex.

For example, after immersing the carrier in a solution of sulfonic acid.

It is easily produced by drying and then heat treatment. The heat treatment temperature is preferably 130 to 300°C.

The sulfonic acids having at least two sulfonic acid groups per molecule used in the present invention include aliphatic, aromatic, alicyclic,
Any kind of aliphatic substance may be used. Examples of such polyvalent sulfonic acids include V1% methanedisulfonic acid, methanesulfonic acid, /, coethanedisulfonic acid, 1.2- and /, J-j rhopanedisulfonic acid 11
11. /, co, j-prohantrisulfonic acid, /, 2-
and/, 3- and/, 4 to rj2. j-phthanedisulfonic acid, benzoso/. 3-disulfonic acid, naphthalene-/, j-disulfonic acid.

naphthalene/, di-disulfonic acid, naphthalene-2
, disulfonic acid, naphthalene, disulfonic acid
@, naphthalene-83. t-) disulfonic acid, /
, 3-cyclohexanedisulfone M, 4t-sulfobenzylsulfonic acid, etc. are used. In such polyhydric sulfonic acids, hydrogen of the organic residue is substituted with other substituents such as 1/10 alkyl group, alkyl group, hydroxyl group, carboxyl group, and amide group.

It may be substituted with a nitro group, 2) an IJ group, an ester group, an aromatic group, or the like. A particularly preferred substituent is /'10, among which a particularly preferred substituent is fluorine. Examples of fluorine-substituted polysulfonic acids include difluoromethanedisulfonic acid, perfluoro- /, 2-ethanedisulfonic acid, perfluoro-1,3-fluoropendisulfonic acid/11111<-fluoropenzone-3-disulfonic acid, etc. are used.

Solid carriers include alumina, silica, silica-alumina, silica-alumina-zirconia, zirconia, titania, boria, (olide, silica-titania, barium sulfate, calcium carbonate, asbestos, bentonite,
Diatomaceous earth, activated carbon.

graphite, polymer, ion exchange resin, activated clay,
Clay minerals are used.

The shape of the carrier is pellet, chip, or S granule.

It may be of any shape, such as spherical or powder.

The catalyst used in the present invention is a complex of these carriers and a polyvalent sulfonic acid having at least one sulfonic acid group per 7 molecules; The above compounds can be used, and one or more of these complexes can be used in the reaction.

The sulfonic acid-containing ring c in the catalyst of the present invention.

Any amount is acceptable, but usually 1 is O0 of the carrier weight! The weight is preferably about 60 to 60, and more preferably about 1 to 60, more preferably about 1 to 60.

The N-phenylcarbamate ester used in the present invention is
A compound represented by the general formula, where R represents an alkyl group, an aromatic group, or an alicyclic group, and R' represents hydrogen, an alkyl group, a halogen atom, a nitro group, a cyano group, an -alkoxy group, an alicyclic group, and an alicyclic group. It represents a substituent such as a ring group, and these substituents are bonded to the ortho or meta position with respect to the urethane group, and r represents an integer of O-da. Furthermore, when r is 2 or more, R' may be the same or different substituents. Furthermore, R may have seven or more hydrogen atoms substituted with the above-mentioned substituents.

Examples of such N-phenylcarbamate esters include, for example, in the above general formula, R is a methyl group, an ethyl group, a 2,2.2-) cycloethyl group, a 2.2.2-)
Lifluoroethyl group, propyl group (n-, 1so-),
Butyl group (n- and various isomers), pentyl group (a- and various isomers), hexyl group (fi- and various isomers)
or an alicyclic group such as a clopentyl group or a hexyl group, or an aromatic group such as a phenyl group or a naphthyl group, and R' is hydrogen or the alkyl group or alicyclic group mentioned above. Examples include N-phenylcarbamate esters, which are group groups, halogen atoms such as fluorine, chlorine, bromine, and iodine, nitro groups, aryano groups, or alkoxy groups having the above-mentioned alkyl groups as constituents.

Preferred is methyl N-phenylcarbamate, N-
Ethyl phenylcarbamate%N-phenylcarbamate--furovir, N-phenyl force lLt J< Miso1
liso-propyl: n-butyl N-phenylcarbamate, N-phenylcarbamate tl1m-butyl, N-
phenylcarbamate xso-phthyl, N-phenylcarbamate t@rt -ph? M-pentyl phenylcarbamate, N-hexyl phenylcarbamate, N
-phenyl, cyclohexyl carbamate, N-phenylcarbamate, 2. -monotrichloroethyl, N-phenylcarbamate, 2.2-trifluoroethyl, N-o or m) IJ methylcarpamate, N-
6 or m-tolyl ethyl rbamate, N-o or m-
) 2,2,2-trifluoroethyl lylcarbamate,
N-o or m-)propyl lylcarpamate (each isomer), N-o or m-butyl tolylcarbamate (each isomer), No- or m-methyl chlorophenylcarbamate, N-o or m- Ethyl chlorphenylcarbamate, N-o or m-propyl chlorphenylcarbamate (each isomer), N-o or butyl chlorphenylcarbamate (each isomer), N-o or m-
Chlorphenyl JL/ /(fuco mate, trifluoroethyl, N-2゜-dimethylphenyl methyl rupamate, N-2, t-D ethyl phenylcarbamate, N-co, dimethylphenylcarbamate Propyl (each isomer), N-2,t-i7°butyl carbamate (each isomer 3N-2,6-9 methylcarbamate, 2,2-trifluoroethyl, N-2,
Methyl 4-dibromphenylcarbamate, N-2, dibromphenylcarbamic acid ethyl, N-2゜bu-
Propyl dibromphenylcarbamate (each isomer)・
, N-6-dibutylcarbamate (dipropylene), N-2,6-dipromphenylcarbamate
! 1) N-phenylcarbamine derivatives such as fluoroethyl are used.

Examples of the methylenating agent used in the present invention include evaformaldehyde, paraformaldehyde, trioxane, tetraoxetine, and dialkoxymethane.

Cyasiloxymethane, /,! -dioxolane, 7.3-
Examples include dioxane, 1,3-dithiane, 1,3-oxinathian, hexamethylenetetramine, and the like, and among these methylenating agents, formaldehyde and paraformaldehyde are particularly preferred.

Trioxane and dialkoxymethanes having a lower alkyl group having 1-4 carbon atoms, such as jetoxymethane, jetoxymethane, dib abo 1, ximethane.

These include cyasyloxymethanes having a lower carboxyl group such as pentanoxymethane, Vhexyloxymethane, and diacetoxymethane% diprobioxymethane, and these may be used alone or in a mixture of two or more.

Chitin, heptane, octane, nonane, decane.

Aliphatic or alicyclic hydrocarbons such as n-hexadecane, cyclopenkune, and cyclohexane, chloroform, notylene chloride, carbon tetrachloride, halogenated hydrocarbons such as dichloroethane, trichloroethane, and tetrachloroethane, methanol, ethanol, Alcohol m such as propatool, butanol, beneine, toluene, xylene, ethylbenzene, monochlorobenzene% diglorpeneine.

Aromatic compounds such as p-nitrotoluene, ethers such as diethyl ether, /, 4t-dioquinane, tetrahydrofuran, methyl acetate, ethyl acetate, methyl formate, etc. Sulfolanes such as ester li, sulfolane, 3-methylsulfolane, 2.4t-dimethylsulfolane, acetic acid, propionic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid.

Examples include carboxylic acids such as trifluoroacetic acid, sulfonic acids such as methanesulfonic acid, trichloromethanesulfonic acid, and trifluoromethanesulfonic acid, and water. These solvents may be used alone or in a mixture of two or more.

The molar ratio of the methylenating agent to the N-phenylcarbamate ester is not particularly limited, but is usually 1 N-phenylcal/(1 mole C of the mate ester to the methylenating agent is preferably used in the range of 0.07 to 70 mol, more preferably in the range of 0.0j-1 mol.If the amount of methylenating agent is too small, unreacted N-phenylcarbamate ester may be used. On the other hand, if the residual ratio is too high, the production ratio of polymethylene polyphenylcarnocimate ester having three or more phenyl groups increases.

In addition, there is no particular restriction on the amount of catalyst used), but when performing a batch reaction, N-phenylcal I (sulfonic acid group of the solid acid is lo-5 to 1 mole of monophosphate).
It is preferable to use an amount that gives O molar equivalent. When carrying out a flow reaction, the flow rate of N-phenylcarbamate is 0.0 /~/
It is carried out in a range of about θθθ mol/hr.

The reaction of the present invention is 2! θ℃ or less, preferably 10 to 2θθ
℃, more preferred temperature is to-i
It is in the range of ro°C.

Further, the method of the present invention is usually carried out under normal pressure or increased pressure, but it can also be carried out under reduced pressure if necessary.

The reaction time varies depending on other reaction conditions such as the reaction temperature, the type and amount of catalyst, the presence or absence of a solvent and its location, the composition of the original scale, and the reaction method, but is usually from several minutes to several hours.

The reaction method of the present invention is not particularly limited, and includes a method in which a solid acid catalyst is suspended in the reaction mixture, a method in which the reaction is performed in a fixed bed, and the like. It may also be carried out in a batchwise manner, or it may be carried out in a continuous manner.

Since the solid acid catalyst of the present invention is solid compared to ordinary liquid acid catalysts such as hydrochloric acid and sulfuric acid, it is less likely to corrode equipment, is easy to separate and recover from reaction liquid components, and is easy to carry out reactions continuously. It has extremely industrial advantages such as not emitting an aqueous solution.

Furthermore, when the catalyst of the present invention is used as a reaction catalyst for N-phenylcarbamate and a methylenating agent, methylene-bis-(4t-phenylcarbamate) can be obtained with high selectivity.

Next, the present invention will be explained in more detail with reference to Examples.
The invention is not limited to these examples.

In addition, the reaction product was analyzed using high performance liquid chromatography.

Example/ 'Diatomaceous earth lθf dried at 10°C under reduced pressure for 1 hour
The samples were immersed in a solution of t, J, and tt methanedisulfonic acids dissolved in 10 - of water and kept at 10°C for 1 hour. Next, use a rotary evaporator for approx. - water was removed, and the residue was separated by F by filtration. Dry the F slag at 160°C for 6 hours,
Then, it was fired at 20θ°C for an additional hour. After firing, the net carrier weight is reduced to /4t1 by cooling in a desiccator. A powdered catalyst was obtained whose weight was increasing.

3t of this catalyst and 1.2 ethyl N-phenylcarbamate
3 F, dimethoxymethane/f, sulfolanta θ-! The mixture was placed in an O-stirring autoclave and reacted at 1170°C for 7 hours. As a result of analyzing the reaction solution, the reaction rate of ethyl N-phenylcarbamate was 16%, and the selectivity of methylene-bis-(4t-phenylcarbamate ethyl) was 73%.

The selectivity of 4t'-methylene di(phenylcarbamate ethyl) was 1/-, and the remainder was polymethylene polyphenylcarbamate ethyl having trinuclear bodies or more. When the catalyst separated from the reaction solution by filtration was used as %f% and the same reaction was repeated, the reaction rate of ethyl N-phenylcarbamate was found! ! -, the selectivity of methylene-bis-(4t-phenylcarbamate ethyl) was 7 points, and 2.4t.
The selectivity of '-methylene-di(ethyl phenylcarbamate) is 12-.

The selectivity of polymethylene polyphenyl ethyl carbamate was /2, and almost the same results were obtained.

The silica-alumina powder containing alumina of Example 20'A was dried at 10° C. for 2 hours under reduced pressure. This sidakar alumina 101 was treated with penyne-/,3-disulfonic acid a, Zt
was immersed in a solution of 10% of water and kept at 20°C for 1 hour. Next, use the rotary evaporator radar! - water was removed and the residue was separated by filtration. F itching 160
The mixture was dried at 0.degree. C. for 6 hours and then calcined at 0.degree. C. for an additional 3 hours. After calcination, the powdered catalyst was cooled in a desiccator to obtain a powdered catalyst whose weight was 22 mm greater than the net carrier weight.

This catalyst 3 and methyl N-phenylcarbamate IO
? ,) lioquinane 0.1 F, nitropenin 30-
When the reaction was carried out in the same manner as in Example 1 at 730°C for 7 hours, the reaction rate of methyl N-phenylcarbamate was ≦2-, which was methyl.

The selectivity for methyl 4t-phenylcarbamate was 2θ and the selectivity for methyl polymethylene polyphenylcarbamate was /IS.

Example 3 20-4tO mesh of silica gel/θ and methane trisulfonic acid! A catalyst having a weight increase of I)/I- from the net carrier weight was obtained in the same manner as in Example 1 using t.

This catalyst was packed into a stainless steel column with an inner diameter of 72 mm and a length of 20 cxa, and a sulfolane solution containing ethyl N-phenylcarbamate/j kg and triochitin/h was added from the bottom of the column at a rate of 30/hr. Injected with.

Keep this column at 130°C.

After reaching a steady state, the product solution was analyzed and the reaction rate of ethyl N-phenylcarbamate was 4t, r, and the selectivity of methylene-bis-(ethyl 4t-phenylcarnocimate) was 701a. However, the selectivity of ethyl polymethylene polyphenyl carbamate was poor.

EXAMPLE A catalyst having a weight increase of 20% over the net carrier weight was obtained in the same manner as in Example 1 using Dageisoru 10f and perfluoro-hecoethane disulfonic acid Qf.

This catalyst was packed into a column similar to that in Example 3.

A nido-a penyne solution containing 10 weight 1 g of butyl N-phenylcarbamate and dimethoxymethane was injected from the bottom of the column at a rate of 10 wl/kr. After maintaining this column at 720°C and reaching a steady state, the product solution was analyzed and the reaction rate of N-phenylcar/(butyl mate was ?r%). The selectivity for ethyl) was 9, and the selectivity for butyl polymethylene polyphenylcarbamate was /21.

Example! Using the same silica gel and difluoromethanedisulfonic acid as used in Example 3, a catalyst with an increased it-weight over the net carrier weight was obtained by a method similar to that in Example 3.

This catalyst was packed into a column similar to that in Example 3.

A sulfolane solution containing 77 parts by weight of ethyl N-phenylcarbamate and 2 parts by weight of jetoxymethane was injected from the bottom of the column at a rate of λ14/br (D).
After maintaining at 0℃ and reaching steady state.

As a result of analysis of the produced liquid, the reaction rate of ethyl N-phenylcarbamate was t2-, the selectivity of methylene-bis-(4t-phenylcarbamate ethyl) was 1r, and the reaction rate of ethyl N-phenylcarbamate was 1r. The selection rate is 1
It was 0%.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] /N-phenylcarpamic acid ester is reacted with methylene lenoto in the presence of a solid acid catalyst consisting of a complex consisting of at least one sulfonic acid having at least two sulfonic acid groups per molecule and a solid support. A condensation method for N-phenylcarbamate ester, characterized by