JPS61103860A - Production of aliphatic isocyanate - Google Patents

Abstract

PURPOSE:To produce an aliphatic isocyanate, easily in high yield, without using pHsgene, suppressing the side reactions, by subjecting an aliphatic primary amine to an oxidative carbonylation reaction under a specific condition, and separating the objective product by the thermal decomposition distillation. CONSTITUTION:An aliphatic primary amine is made to react with molecular cxygen and carbon monoxide at 140-240 deg.C in the presence of a catalyst composed of an aromatic hydroxyl compound having a pka of <=11, Pd, Rh or their compound, and a compound containing I or Br, to obtain a carbonylation reaction product composed mainly of an aliphatic isocyanate and containing a urethane compound as a by-product. The reaction mixture is treated at 100-300 deg.C to effect the thermal decomposition distillation comprising the decomposition of the urethane compound in the carbonylation reaction product to an aliphatic isocyanate and an aromatic hydroxyl compound, and at the same time, the separation of the component having lower boiling point in the aliphatic isocyanate and the aromatic hydroxyl compound.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing aliphatic insiacate. More specifically, the present invention relates to a method for producing aliphatic isocyanate in high yield from aliphatic/a-amine, -carbon oxide, and molecular oxygen.

[Conventional technology]

Conventionally, aliphatic isocyanates have been produced by reacting aliphatic/amines with phosgene;
1J, and furthermore, the product may contain hydrolyzable chlorine compounds, making it extremely difficult to remove these byproducts. )K mouth? A manufacturing method is desired.

On the other hand, it was already known that aliphatic isocyanates can be produced in a yield of about jOfa by reacting aliphatic 7th-class amines with carbon monoxide and a stoichiometric amount of palladium chloride. (E, W, 5lern et al.', 1.O
rg, Chem,, Jth/Q, No.! 6 pages,
[Problems to be solved by the invention] However, this method requires more than an equivalent amount of sodium hydrogen phosphate as a dehydrochlorination agent, and does not require a catalytic reaction, but involves the reduction of palladium chloride to metallic palladium. It is carried out industrially because the reaction stops due to the reaction, the reaction time is very long (92 to 60 hours), and the yield is low (
The second one was a long way off.

Also, Special Publication No. 4tj-6!0 (and J, Tsujt
et al., Chan, Corm+un,, 1st page ♂j,
'/946), a similar reaction was also reported,
This method also uses stoichiometric amounts of palladium chloride and allyl halide, and it is not a catalytic reaction; the palladium turns into pialyl fibers and the reaction stops, and the yield is very low (1:1), so it is not suitable for industrial use. It was not something that could be implemented. [Means for Solving Problem C] Therefore, the present inventors conducted extensive research in order to find a method for producing aliphatic isocyanate from aliphatic/a-amine at a reasonable yield without using phosgene. As a result, an oxidative carbonylation reaction in which an aliphatic/a amine is reacted with monomolecular oxygen and carbon monoxide in a specific temperature range in the presence of a specific aromatic hydroxyl compound, supported by a specific catalyst system,
It was found that a carbonylation reaction product containing an isocyanate compound as the main product and a phrethane compound as a by-product can be obtained in good yield, and furthermore, thermal decomposition was carried out to convert the phrethane compound in this carbonylation reaction product into isocyanate. Anticipating that the objective could be easily achieved by combining the method with a reactive distillation method, the present invention was completed.1:
It's arrived.

That is, the present invention provides a method for producing an aliphatic isocyanate from an aliphatic/i amine, comprising: (a) molecular oxygen; 1) an aromatic hydroxyl compound having pKa of // or less; and Ii) palladium or rhodium and in the presence of a catalyst system consisting of at least seven compounds selected from among compounds containing iodine or bromine; /naθ~24
By reacting with carbon monoxide in the temperature range of tθ℃, the power to make aliphatic isocyanate the main product and phletane compound as the by-product! a carbonylation step to obtain a levonylation reaction product, and (b) the obtained carbonylation reaction product is
By treatment at a temperature of ~300°C, the phrethane compound in the carbonylation reaction product is decomposed into aliphatic isocyanate and aromatic hydroxyl compound, while the lower of the aliphatic isocyanate or aromatic hydroxyl compound is decomposed. A method for producing fatty Fv group 5 isocyanates, characterized in that an aliphatic inanate and an aromatic hydroxyl compound are separately recovered by carrying out a separation step including pyrolysis reaction distillation to extract boiling point components in gaseous form. be.

The carbonylation step of the present invention is characterized in that a carbonylation reaction product containing an isocyanate compound as a main product and a urethane compound as a by-product is obtained,
Although its formation mechanism is unknown, the reaction results show that aromatic hydrocoyacyl compounds with pKa of // or below, such as A
When a compound represented as rOH is used, it is represented by the following general formula.

R(NH2) n+n -Co-1-)n ・02+(
m)'+nz) ・ArOH→X-R(NCO)n+
2-R(NHCOOAr)m(NCO)n-,.

+z-R(NHCOOAr)n+n・Hρ (wherein, R is a monovalent aliphatic group, Ar is an aromatic group, m and n are integers of 7 or more, x, y, z:・0 or It is a positive number and satisfies x + y + z = /, X loss is 0. This urethane compound is decomposed and separated into aliphatic isocyanate CpKa /
/ Since it is a compound to which the following aromatic hydroxyl compound is added, fatty isocyanate C: compared to a compound to which alcohol, which is an aliphatic hydroxyl compound, is added,
It is characterized in that its decomposition occurs very easily, and it is also characterized in that this decomposition reaction is carried out by distillation separation and simultaneous thermal decomposition reaction and distillation. This thermal decomposition reaction is expressed, for example, by the following general formula.

y-R(NHCOOAr)m(NCo)
n −m + t −H(NHCOOA r ) n(
y+z) ・R(NCO)n+(my+nz) ・Ar
OH Palladium, rhodium, or their compound C used in carbonylation step 1 of the method of the present invention is not particularly limited as long as it contains palladium and/or rhodium, and these elements are in a metallic state. It may also be a component that forms a compound. Also,
These catalyst components include, for example, activated carbon, graphite, silica, alumina, silica-alumina, silica tetania, titania, zirconia, paricum sulfate, eta lucicum carbonate, asbestos, bentonite, diatomaceous earth, polymers, ion exchangers, zeolites, It may be supported on a carrier such as molecular 7-b, magnesium silicate, magnesia, or the like. Palladium and rhodium in the metallic state include those obtained by supporting catalyst components containing these metal rings and these metal ions on the above-mentioned carriers and then reducing them with hydrogen or formaldehyde. Alloys or intermetallic compounds containing metals may also be used.Also, the alloys or intermetallic compounds may be of palladium and rhodium, or may contain other elements such as selenium, tellurium, iron, antimony, It may also contain bismuth, copper, silver, gold (in song 2), tin, vanadium, iron, cobalt, nickel, watermelon, lead, talicum, chromium, molybdenum, tungsten, and the like.

On the other hand, as compounds containing palladium or rhodium,
For example, inorganic salts such as halides, sulfates, nitrates, phosphates, phocates, and acetates.

Contains organic acid salts such as oxalates and formates, cyanides, hydroxides, oxides, sulfides, and anions such as nitro groups, anno groups, halogens, and yucate ions. Metal salts and complex compounds of metals such as salts or complexes containing ammonia, amines, phosphines, -oxidized orthogonals, chelate ligands, etc., and walled metals having any number of ligands or groups. Examples include compounds.゛Such catalyst components include, for example, Pd black, Pd
0%Pd Al2O3, Pd5i02, Pd
-T i 02, Pd -Z r OX, Pd Ba
SO4, PdCa CO3, Pd-asbestos,
Supported palladium catalysts such as Pd-zeolite and Pd-molecular rape: Pd-pb, Pd-3e,
Pd-Te%Pd-Hg%Pd-TI,
Pd-P, Pd-Cu.

Pd-Ag, Pd-Fe, Pd-Co,
Alloys or intermetallic compounds such as Pd-Ni, Pd-Rh, and any alloy or intermetallic compound supported on the above-mentioned carriers (- supported, Pdel, PdBr2, Pd
I2, pd(NO3)z, PdSO4, salt a, Pd (OCOCH,),,vu') acid/(ra9
') Organic acid salts such as la, Pd(CN),, Pd0
1PdS.

Palladate m represented by MzCPdXaJ,M, (PctX,) (M represents an alkali metal or ammonium ion, and X represents a nitro group or a cyan crystal or) chloride. ), (Pd(N)Is)a)Xs, (P
ammine complexes of palladium such as d(en)z)Xz (X has the same meaning as above and en represents ethylenediamine), pdcI, (PhCN), PdCl, (
PR,),, Pd(CO)(PR,),1, pd (
PPh3)n, PdC Otori(R)(PPh3)t
, Pd(CZH4)(PPhx)* , pd(
C3) Dark compounds or organometallic compounds such as (s)t (
(R stands for rhizome), complex compounds coordinated with chelate ligands such as Pd(acac)z, Rh', supported rhodium catalysts similar to Pd, Rh alloys or intermetallic compounds similar to Pd. Compounds and these supported on carriers, R)
+CI, and hydrate, RhBr3 and hydrate, RhI
.

and hydrates, non-salts such as Rhz(Son)s and hydrates, Rh2(OCOCHh)4, Rh,03, Rh0
1, Mx(RhXa) and hydrate (M, X have the same meanings as above), (Rh(NHs)i)Xs, C
Ammine complexes of rhodium such as Rh(en)s)Xs, rhodium carbonyl clusters such as Rh4(Co)xz, Rh5(CO)+s, (RhCI(C
o), ), RhC11(PRs)s, RhCI(PP
hn)s, RhX(CO)I, (X has the same meaning as above, L is a ligand consisting of an organic phosphorus compound and an organic arsenic compound), RhH(CO) (PPh,)
, and other dark compounds or organometallic compounds.

In the carbonylation step of the present invention, these palladium metals, rhodium metals, or compounds containing palladium or rhodium may be used alone or in a mixture of seven or more types, and the amount used may vary. There is no particular restriction on the amount, but usually the platinum group element-containing component is 0.000/~! with respect to the 7th class amine! A range of 0 molar coefficient is desirable.

The iodine- or bromine-containing compound used in the carbonylation step of the present invention may be either 4M or inorganic as long as it is an iodine- or bromine-containing compound that does not contain palladium or rhodium. compound, metal bromide, onicum iodide compound, onium bromide compound, compound capable of producing an iodide or onium bromide compound in a reaction system, iodine oxo acid or its salt, bromine oxo acid or its salt, A complex compound containing iodine, a complex compound containing bromine, an 81-iodide, a gastric bromide, iodine, bromine, etc. are preferably used.

As the iodide or bromide of a specific alkali metal or an alkaline earth metal, a bromide is preferable.

Examples of bromides or iocides of alkali metals and alkaline earth metals include lithium bromide, sodium bromide, rubidicum bromide, sesicum bromide, magnesium bromide, stronticum bromide, barium bromide, lithium iodide, and iocide. Compounds of a single metal and a single halogen such as sodium chloride, potassium iodide, rubidicum iocide, sesicum iocide, magnesium iodide, stronticum iocide, palifum iocide, magnesium bromide Double salts such as potassium bromine fluoride, potassium iodide chloride, rubidium iodine chloride, sesicum iodine chloride,
Iodine chloride bromide sencum, iodine rubidicum bromide chloride,
Examples include polyhalides such as iodine kalicum bromide, iodine bromide sevum, and iodine rubidicum bromide.

・Onium iodine compounds or onium bromide compounds are compounds containing elements with lone pairs of electrons. Elements have increased coexisting bond valences to become neighboring ions, and have an iodine anion or a bromine anion as a counter ion.

Such onium compounds include ammonium compounds (r-R'R2T<3R4:U■)XO), phosphonicum compounds ((R2R3R4p■)XO), arsonium compounds ((RIR2R"R'As0IXO), Compounds ((RIR21■)XO) etc. are special
Two preferred. Here, R1, R2, R3, l(' represents hydrogen or a group selected from an aliphatic group, an aromatic group, an alicyclic group, an araliphatic group, and a heterocyclic group, and each is the same and Alternatively, in some cases, it may be a constituent element of a ring containing an element having a lone pair of electrons. Also, X represents Br or ■.Of course, if two or more such onium groups are present in the molecule Furthermore, 1: may be a polymer containing such an onium group in the main chain or side chain.

Such an onium halide compound whose anion is iodine or bromine can be reacted with a hydrogen halide or a corresponding amine or nitrogen-containing compound, phosphine compound, arunne compound, etc. Ease 1: These can be obtained, and these may be produced outside the reaction system, or may be produced within the reaction system. Of course, it may be produced by other methods, or may be produced within the reaction system by other methods.

Among these, particularly preferred are halogenated ammonium compounds and halogenated phosphonium compounds in which the halogen is iodine or bromine. A halogenated ammonium compound can be easily obtained by reacting a corresponding nitrogen-containing compound with a hydrogen halide, or by reacting a nitrogen-containing compound with an alkyl halide or an aryl halide.

Examples of such nitrogen-containing compounds include ammonia, amines such as 7th-class amines, secondary amines, and tertiary amines, hydroxylaminos, hydrazines, hydrazones, amino acids, oximes, imidoesters, These include amides and various nitrogen-containing heterocyclic compounds.

Examples of quaternary ammonium halides in which the halogen is iodine or bromine include halogenated tetramethylammonium, halogenated tetraethylammonium, halogenated tetrabutylammonium, halogenated trimethylethylammonium, halogenated dietherdibutylammonium, etc. aliphatic quaternary ammonyl ammonium halides, ring group quaternary ammonium pallides such as halogenated N,N,N-trimethylnochlorohexylammonicum, halogenated tetrapendylammonicum, halogenated trimethylbenzylammonicum Aromatic quaternary ammonium pallides such as halogenated N, N, N-trimethylphenylammonicum, halogenated N.

N, N-)! Aromatic quaternary ammonium pallides such as J ethylphenylammonicum, halogenated N-methylpyridinium, halogenated N-ethylquinolinicum, halogenated N, N-dimethylpiperidinicum, halogenated N, Heterocyclic quaternary ammonium halides such as N'-dimethylimidazolinium are preferably used.

Examples of halogenated phosphonium compounds in which the halogen is iodine or bromine include halogenated tetramethylphosphonium, halogenated tetraethylphosphonium,
Symmetrical tetraalkylphosphonium compounds such as halogenated tetrabutylphosphonium, asymmetrical tetraalkylphosphonium compounds such as halogenated ethyltrimethylphosphonium, halogenated dietherdimethylphosphonicum, halogenated tetraphenylphosphonium, halo-
Symmetrical tetraarylphosphonium compounds such as tetra(p-tolyl)phosphonium genide, halogenated (α-
Asymmetric tetraarylphosphonium compounds such as (naphthyl)triphenylphosphonium, alkylar 9-al mixed phosphonicum compounds such as halogenated methertriphenylphosphonicum, halogenated phenyltrimethylphosphonium, and tetraalkylphosphonium such as halogenated tetrabenzylphosphonium Compounds and the like are preferably used.

Oxoacids of iodine or bromine and their salts have a positive oxidation number of /, 3,! , 7 of iodine or bromine oxygen acids and their salts, specifically, hypoiodious acid, bromic acid, perbromic acid, hypoiodite, iodic acid, iodic acid, and orthoperiodic acid. , metaperiodic acid and salts of these acids. The cations of salts may be of any kind, such as ammonium ions and various metal ions.
Particularly preferred are alkali metal ions and alkaline earth metal ions. Among these salts, @C bromite salts such as sodium bromate, lithium bromate, sodium bromate, calicum bromate, rubidium bromate, sencum bromate, magnesium bromate, carunium bromate, etc. Acid salts, perbromates such as calicum persodide, sodium hypoiodite, calicum hypoiodite, rubidium hypoiodite, cesium hypoiodite, calcium hypoiodite, hypoiodite Hypoiodates such as barium acid, suticum iodate, sodium iodate, calicum iodate, calicum hydrogen iodate, rubidicum iodate, cesium iodate, magnesium iodate, calcium iodate, iodic acid Strontium, iodate salts such as baricum iodate, periodic acid acidum, sodium metaperiodate, trisodium dihydrogen orthoperiodate, disodium dihydrogen orthoperiodate, potassium mekperiodate , orthoperiodate trihydrogen-caricum,
Perbromates such as tripotassium hydrogen dimesoperiodate, rubidicum periodate, sesicum periodate, and palicum periodate are preferably used.

The iodine- or bromine-containing complex compound may be any cationic or anionic iodine- or bromine-containing compound, such as ammonium dichlorobromate, tetramethylammonium tetrabromoiodate, etc. Polyhalogenated halogen acid salts, potassium hequinaiodotellurate,
Iodinated or brominated acid salts such as tetraethylammonium tetraiodomercurate, potassium tetraiodobismuthate, sodium tetrabromostelate, cesium tetrabromoferrate, barifum hexaiodostannate, potassium tetraiodolearate, potassium hequinapromotellurate, etc. , tris(pyridine)chromium tripromide, tris(pyridine)molybdenum tribromide, hexaamminecobalt tripromide, bis(2°2'-bipyridine)copper josite, and other complexes with different ligands.

In addition, an organic iocide or a specific bromide is defined by the general formula % (in the formula, R6 is an m-valent am group, X is B, or i, m is 7
means an integer greater than or equal to ), and when m is 2 or more, X may be a different halogen species. Furthermore, the halogen X may be bonded to a heteroatom other than carbon, such as nitrogen, phosphorus, oxygen, sulfur, or selenium.

Also, iodine molecules or bromine molecules themselves can be used.

Only seven types of such compounds containing iodine or bromine may be used, or two or more types may be used in combination.

The iodine- or bromine-containing compound is usually used in an amount of 0.00 to 0.000 times the mole of parachrome, rhodicum or their compound used, more preferably 0.00 times the amount of the metal used. It is used in a range of 7 to 100 times the mole.

Among these catalyst systems, particularly preferred are systems in which parachrome or a compound containing parachrome is combined with iodine or a compound containing iodine.

The aromatic hydroxyl compound used in the present invention has a hydroxyl group directly bonded to the aromatic group and has a pKa of // or less.

It can be anything. For example, phenol:
Cresol C (each 'A isomer), xylenol (each isomer)
, various alkylphenols such as ethylphenol (each isomer), propylphenol (each isomer); anisole (each isomer), etquinphenol (each isomer)
Various alkoxyphenols such as; chlorophenol (each isomer), bromophenol (each isomer), dichlorophenol (each isomer), halogenated phenol such as dibromophenol: methylchlorophenol (each isomer), Alkyl- and halogen-substituted phenols such as ethylcucolphenol (each isomer), methylbromophenol (each isomer), and ethylbromophenol: [X is a simple bond, or -〇-1-S-1-8O, - 1
-CO-1-C)(, -1-C(R2) -(R is lower alkyl, sai), etc., and the aromatic ring represents a halogen, an alkyl group, an alkoxy group, an ester group,
It may be substituted with a substituent such as an amide group or an ano group. ] Various substituted phenols represented by naphthol (each isomer) and various substituted naphthols; Aromatic hydroxyl compounds; Aromatic dihydroxy compounds such as hydroquinone, resorcinol, catechol, naphthoquinone, anthraquinone, and their alkyl-substituted or halogen-substituted dihydroxy compounds: (X
is as described above, and the aromatic ring may be substituted with a substituent ζ such as a halogen, an alkyl group, an alkoxy group, an ester group, an amide group, or an ano group. ) Aromatic dihydroxy compounds represented by: nitro-substituted aromatic hydroxyl compounds such as nitrophenol (each isomer), nitronaphthol (each isomer), nidianophenol (each isomer), cyanonaphthol (each isomer), etc. is used.

Only seven types of such aromatic hydroxyl compounds may be used, or a mixture of two or more types may be used.

In the present invention, by using an aromatic hydroxyl compound having a pKa of // or below (it is possible to obtain a carbonylation product containing an isocyanate compound as a main component). If an aromatic compound and a compound are used, a carbonylation product containing a phrethane compound as the main component is obtained, so it is not preferable for obtaining an isocyanate compound as the main product in the carbonylation process.From this point of view, More preferred aromatic hydroxyl compounds have a pKa of 10,! or less.

The amount of aromatic hydroxyl compound used in the carbonylation step is preferably such that the number of hydroxyl groups is 1 mole or more per 1 mole of amino group of the 7th class amine used. More preferably, the amount of hydroxyl group used is 5 moles or more, and even more preferably 10 moles or more, per mole of amino group. If the amount of the aromatic hydroxyl compound is less than 2/mol per amino group of the 7th class amine, a urea compound will be produced as a by-product, which is not preferable.

The aliphatic/9i amine used in the present invention may be any amine in which seven or λ or more seventh-class amino groups are bonded to an aliphatic carbon atom; It may also be an amine or an araliphatic/a-diamino.

Examples of such aliphatic 7th class monoamines or polyamines include methylamine, triamine, propylamine (each isomer), butylamine (each isomer), pentylamine (each isomer), and hexylamine (each isomer). body),
Aliphatic/class monoamines such as dodecylamine (each isomer); ethylenediamine, diaminopropane (each isomer)
, diaminobutane (each isomer), diaminopentane (each isomer), diaminohexane (each isomer), diaminodecane (each isomer) and other aliphatic 7th-class diamines: /, 2.
3-) Riaminopropane, triaminohechitin (each isomer), triaminononane (each isomer).

Triaminododecane (each isomer), /J-diamino-guaminomethyl-octane, 2,6-diamizcaproic acid co-aminoethyl ester, /,! , 6-dolyaminohequinane, /, t! s, // -) aliphatic/class triamines such as riaminoundecane; cyclopropylamine,
Ring groups such as cyclobutylamine, cyclopentylamine, cyclopentiamine, diaminocyclobutane, diaminocyclobutane (each isomer), 3-aminomethyl-3,ta, j-trimethylcyclohexylamine, triaminone clohexane (each isomer) Seventh class mono- and polyhomone order; benzylamine, di(aminomethyl)benzene (each isomer), aminomethylpyridine (each isomer), di(aminomethyl)pyridine (each isomer), aminomethylnaphthalene (each isomer) ), di(aminomethyl)naphthalene (
various isomers), aromatic aliphatic 7th class monomers, and polyamines.

In addition, in the aliphatic groups, alicyclic groups, and aromatic groups that make up the skeletons of these 7th-class amines, some of the hydrogens are halogens, alkyl groups, alkoxy crystals, aryl groups, noano groups, and ester groups. The skeleton may be substituted with a substituent such as a sulfone bond, an unsaturated bond, an ether bond, an ester bond, a thioether bond, a sulfone bond,
It may also contain a ketone bond.

In the carbonylation step of the present invention, it is preferable to use an aromatic human mixyl compound as a solvent, but other suitable solvents can also be added.

Such solvents include, for example, aliphatic hydrocarbons such as pentane, hexane, heptane, octane, and decane; ring hydrocarbons such as dichlorohequitin, tetralin, and detriline; benzene, toluene, kylene, menthylene, etc. Aromatic hydrocarbons; Nitriles such as acetonitrile and benzonitrile; Sulfones such as sulfolane, methylsulfolane, and dimethylsulfolane; Ethers such as tetrahydrofuran, /, cudiochitin, /, cordimethoxyethane; Ketones such as acetone and methyl ethyl ketone Types: Examples include esters such as ethyl acetate and ethyl benzoate.

Furthermore, halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, fluorobenzene, chlorotoluene, chlornaphthalene, and fromnaphthalene; chlorhequitine, chlorochlorohexane, trichlorotrifluoroethane, methylene chloride, and tetrachloride; Halogenated aliphatic hydrocarbons such as carbon or halogenated aliphatic hydrocarbons are also used as solvents.

The molecular oxygen used in the carbonylation step of the present invention is pure oxygen or a substance containing oxygen, which may be air, or other gases such as oxygen, argon, helium, etc. that do not inhibit the reaction with air or pure oxygen. , or diluted with an inert gas such as carbon dioxide. Also in some cases.

It may also contain gases such as hydrogen, carbon oxides, hydrocarbons, and halogenated hydrocarbons.

Moreover, in the carbonylation step of the present invention.

It is necessary to carry out the reaction in a temperature range of /4tθ to 24tθ°C. If the reaction is carried out at a temperature lower than /4tO°C, the amount of urethane compounds and urea compounds will increase, the reaction will be slow, or the reaction will hardly occur, which is not preferable. Furthermore, if the reaction is carried out at a magnetism higher than 2110° C., side reactions will increase and the yield of isocyanate will decrease, which is not preferable. In this sense, a more preferable temperature range is 750 to 0°C.

In addition, the reaction pressure in the carbonylation step is /~jθ0Kp/f
fl, preferably ko0~j00Ky/aA,
The reaction time varies depending on the reaction system, catalyst system, and other reaction conditions, but is usually several minutes to several hours.

The inventive carbonylation step can also be carried out batchwise;
A continuous system in which the reaction components are continuously supplied and the reaction solution is continuously extracted is also effective.

In addition, in the carbonylation step, other additives can be added to the reaction system as necessary to make the reaction more efficient. Such additives include molecular sheep, etc., which have a dehydrating effect. Especially (: preferred.

In the second step of the present invention, the carbonylated product produced in the carbonylation step is treated at a temperature of 100 to 300°C to convert the urethane compound in the carbonylated product into an aliphatic innoanato compound and an aromatic compound. By carrying out a separation process that includes a pyrolysis reaction distillation in which the low boiling point components of the aliphatic isocyanate or aromatic human mixyl compound are extracted in gaseous form while decomposing the aliphatic isonoanate and the aromatic human mixyl compound, The target aliphatic innoanate is produced by separately recovering the group hydroxyl compound and the group hydroxyl compound.

In this way, in the present invention, a carbonylation product containing an aliphatic isocyanate compound as a main component and a urethane compound as a subcomponent is produced in the carbonylation step, and then a urethane compound as a by-product is converted into an aliphatic isocyanate compound. The present invention is characterized in that it combines a method of separating the compound and the aromatic hydroxyfur compound by thermal decomposition reaction and distillation.

Therefore, it is clear that the method of the present invention has the following advantages when implemented industrially.

(1) The urethane compound produced in the carbonylation step is a compound in which an aromatic hydroxyl compound with pKa below //J21 is added to an aliphatic isocyanate.
Compared to urethane compounds to which aromatic hydroxyl compounds with a pKa greater than 77 are added, they can be thermally decomposed at lower temperatures;
In addition, compared to ordinary urethane compounds to which alcohols have been added, it can be thermally decomposed easily at lower temperatures (1), so side reactions of isocyanate compounds that tend to occur during immobilization are suppressed, and isocyanate compounds can be produced in high yields. Can be manufactured.

+21 It is a thermal decomposition reaction distillation method in which isocyanate compounds generated by thermal decomposition are distilled at the same time as they are generated (therefore, they are separated from aromatic hydroxyl compounds).
Since the residence time at the thermal decomposition temperature is short, the side reaction 1 of the isocyanate compound: The formation of polymeric substances is extremely suppressed, and the isocyanate compound can be produced in high yield.

(3) Since the thermal decomposition temperature is low, thermal decomposition 1: less thermal energy is required.

(4) The urethane compound to be thermally decomposed is a regular product in the carbonylation process, and is quantitative! = Less thermal energy is required for thermal decomposition.

The carbonylated product produced in the carbonylation step contains aliphatic isocyanate compounds as a main component, but these may be separated before the pyrolysis reaction distillation of the frethane compound. It is preferable to introduce it into the thermal decomposition reaction distillation stage as it is without separation, and to distill and separate it together with the same aliphatic isocyanate compound produced by the thermal decomposition. Further, in the carbonylation step, the aromatic hydroxyl compound is usually used in excess, so that it exists as a mixture with the carbonylation product after the reaction. The carbonylated product separated from this mixture may be introduced into a pyrolysis reaction distillation FC,
The aliphatic isocyanate compound and the aromatic hydroxyl compound may be separated by introducing the mixture as it is into a thermal decomposition reaction distillation apparatus without separation.

In this sense, preferred aromatic hydroxyl compounds are those that exhibit a boiling point difference of at least 10° C. with respect to the target aliphatic isocyanate under thermal decomposition reaction distillation conditions. Even more preferred is the use of an aromatic hydroxyl compound whose boiling point is at least 101 times higher than the boiling point of the target aliphatic isocyanate under pyrolysis reaction distillation conditions. In this case, the aliphatic isocyanate is separated as a gas phase component, and the aromatic hydroxyl compound, which is a high-boiling point compound, is recovered as a liquid phase component, either as it is, or after some purification, or recycled in the carbonylation step. It is also not necessary to separate the aromatic hydroxyl compounds present in excess before the pyrolysis reaction distillation.

In addition, when carrying out this pyrolysis reaction distillation, in addition to the carbonylation product or a mixture of the carbonylation product and the aromatic hydroxyl compound (:, it is also possible to use a solvent inert to the isocyanate, This is a preferred method in some cases.

Such solvents include substituted or unsubstituted hydrocarbons or mixtures thereof, for example aliphatic, ring ring or aromatic, and also include certain oxygenated compounds such as ethers, ketones and esters. .

In addition, in the separation process including thermal decomposition reaction distillation, low-boiling components of aliphatic isocyanates or aromatic hydroxyl compounds are separated in gaseous form by distillation, but in order to accelerate this separation, inert gas, For example, it is also a preferable method to introduce nitrogen, helicum, argon, carbon dioxide, methane, ethane, propane, etc., singly or as a mixture into the reaction system. Organic solvents 1 For example, /NC7 generated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride, low-plate hydrocarbons such as pentane, hexitine, heptane, and benzene, and ethers such as tetrahydrofuran and dioxane can also be used. .

Further (;, lowering the temperature of pyrolysis reaction distillation,
A thermal decomposition catalyst can also be used for the purpose of increasing the reaction rate. Such catalysts include, for example, rare earth elements,
Elemental antimony, bismuth and oxides, sulfides and salts of these elements; elemental boron and boron compounds: steel group, benthide group, aluminum group, carbon group of the periodic table,
Titanium group metals and oxides and sulfides of these metals: Carbides and desirably compounds of elements of the carbon group other than carbon in the periodic table, titanium group, vanadium group, and chromium group are preferably used.

When a catalyst is used, the ratio between these catalysts and the urethane compound can be adjusted to any degree, but it is preferable to use the catalyst in an amount of usually 0.000 to 100 times the amount of the urethane compound.

In the separation step including thermal decomposition reaction distillation of the urethane compound, the temperature at which the carbonylation reaction product is treated is 100 to 300.
℃ range. More preferable range is 720-210℃
It is. If the temperature is lower than 100°C, the decomposition reaction is slow or hardly decomposed, which is industrially unfavorable. If the temperature is lower than 300°C, side reactions occur and the yield is reduced, which is unfavorable.

Further, the reaction time of thermal decomposition in the separation step including this thermal decomposition reaction and distillation varies depending on the type of polyurethane to be decomposed, the solvent, the catalyst, etc., the reaction temperature, etc., but is usually from several minutes to several tens of hours. Preferably it is several minutes to several hours, and the shorter the better.

In addition, this separation process including thermal decomposition reaction distillation can be carried out under any pressure, including normal pressure, reduced pressure, and increased pressure, so it is possible to The optimum reaction pressure determined by the presence or absence of a decomposition solvent, its type, etc. is adopted.

Furthermore, the type of equipment used in the separation process including this thermal decomposition reaction distillation is not limited in any way; for example, the urethane compound is heated while the carbonylation reaction product is flowing down inside a pseudo-tubular equipment. A method in which low boiling point components of the aliphatic isocyanates or aromatic hydroxyl compounds present in the system are taken out in gaseous form from the upper part of the apparatus, and high boiling point components are taken out from the lower part of the apparatus and separated and recovered separately. , thermally decomposed using a seed type device and 1= in the system.
Preferably used are a method in which the existing low-boiling components are collected in a gas phase, separated and recovered, and a method in which these are combined. Furthermore, if necessary, a distillation column and/or partial condenser may be provided above these devices.

Further, this separation step can be carried out by either a batch method or a continuous method.

The method of the present invention is suitable for producing aliphatic monoisocyanates, aliphatic diisocyanates, and aliphatic polyisocyanates, and is also suitable for producing hexamethylene diisocyanate, which is used in large quantities industrially. This is a method.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

Example/ Hexamethylene diamine/2. r mmol, phenol 22
, Palladium black 0. jηatom, yokuka natricum/
mmol was added and the system was replaced with carbon monoxide, then -carbon oxide was added to 75 KgloA, and then air was added to 3! Kp/ff
The total pressure was set to I/OKgloA. After the carbonylation reaction was carried out at 710°C for an hour without stirring, the entire amount of palladium black was separated and recovered by passing the reaction mixture through the mouth.

Analysis of the reaction mixture showed that the reaction rate of hexamethylene diamine was 100%, and hexamethylene diisocyanate was converted to 7-isocyan-6-tomonocretan/-isocyanate-4-phenoxycarbamoyl- with a yield of 23%. Chitin is / chitin yield, dicletane /
, 6-difninoxycarbamoyl-hechitin was found to be produced at a yield of 7.

In addition, when sodium iocodide was not used, this carbonylation reaction hardly proceeded.

Next, the reaction mixture obtained in the carbonylation step is placed in a simple distillation apparatus consisting of a three-bottle flask equipped with a thermometer, an i-line inlet extending below the liquid level, and a Liebig condenser, and the heated to 200℃ and 30t of nitrogen
/Introduced at the time. Carbonylation reaction C: The water thus produced and most of the phenol were distilled off at temperatures up to 715°C. At this time, the thermal decomposition reaction was also progressing at the same time.
Further, the external temperature was raised to 210° C. and held for 10 minutes to carry out thermal decomposition reaction distillation, thereby almost completely distilling off the generated phenol. Phenol is approximately /θ0
The person was recovered. By distilling the obtained residual amount under reduced pressure, hexamethylene diisocyanate distilled at 726 ~ / j 7 C // θ Hg /, wa! ? (Yield: 92, male based on hexamethylene diamine).

Example: 5 grams of para-cresol instead of cophenol? The carbonylation reaction was carried out in the same manner as in Example except that the reaction rate of hexamethylenediamine was 100%,
Hexamethylene diisocyanate has a yield of 62, /-
It was found that isocyanato-6-(p-methylphenoxy)carbamoyl-hexitin was produced in a yield of 3.5%, and di(p-methylphenoquine)carbamoyl-hexitin was produced in a yield of 3.theta.

Para i) The reaction mixture from which the black cum was removed by mouth filtration was prepared in the same manner as in Example, and the external temperature of the flask was adjusted to 210°C.
The temperature was maintained at ℃, and a pyrolysis reaction distillation was carried out in which p-cresol was distilled simultaneously with the pyrolysis reaction. After recovering the entire amount of para-cresol, the remaining amount was distilled under reduced pressure.
Hexamethylene diisocyanate/, 93y (yield 9/93y based on hexamethylene diamine) was obtained by distillation at 726-/27°C//θran Hg.

Example 3 Parachlorophenol instead of phenol! 2. The carbonylation reaction was carried out in the same manner as in Example except that 7 mmol of tetramethyiodide/L/77monim9 was used instead of sodium iodide. As a result, the reaction rate of hexamethylene diamine was 10θ, Hequinamethylene isocyanate with a yield of 7.

It was found that /-isocyanate-6-(p-chlorophenoxy)carbamoyl-hexane was produced at a yield of /j%, and di(p-chlorophenoxyV)carbamoyl-hexane was produced at a yield of j%. .

The reaction mixture, from which the palladium black had been removed by sieving, was placed in a three-loaf flask similar to that used in Example/. However, in this case, the nitrogen inlet was a capillary tube, and the entire system was maintained at 300 wHgC. The external temperature of the flask of this decomposition reaction distillation apparatus was maintained at 2-20°C, and a thermal decomposition reaction was carried out simultaneously with the distillation of parachlorophenol.

After recovering the entire amount of parachlorophenol, the remaining amount is distilled under reduced pressure to /2~/core℃//O
Hexamethylene diisocyanate/, 9 gF (92.4 based on hexamethylene diamine) was obtained by distillation at tm Hg.

Example 9 - In the same manner as in Example except that various halogen compounds shown in Table 7 were used instead of sodium taiodide,
Carbonylation reaction, thermal decomposition reaction and distillation separation were performed, and hexamethylene diisocyanate was obtained by distillation under reduced pressure.

The results are shown in Table 7.

Here, HMDI is hexamethylene diisocyanate,
HMTU represents /-isocyanate-6-funinoquine carpomoyl-hechitin, 1 (MDU represents 7,6-difninoquine carbamoylhexane. The yield is a value based on the hexamethylene diamine used.

Table 7 Example IO Paraphenylphenol ♂θ instead of phenol? The carbonylation reaction was carried out in the same manner as in Example, except that the yield of hexamethylene diisocyanate was 4%. Hexane is collected; 4-/
♂H/, O-di-(p-phenylphenoxy)carbamoyl-hexane was obtained in terms of yield/θ.

This carbonylation reaction mixture was subjected to thermal decomposition reaction and distillation separation in the same manner as in Example 3. Flask bath temperature 210
℃, and the pressure inside the system was set to ir.

m Hg, and hequinamethylene diisocyanate produced by thermal decomposition was distilled out. Hequinamethylene diisocyanate of /, 10% (yield: 90% based on hexythylene diamine) was obtained.

Example/l n-butylamine 2.3? , parachlorophenol! 0
02, Pd/5iO1/ with 10 mmol of sodium iodide and j% of palladium supported on the glue gel! ? as well as/
After carrying out the carbonylation reaction in the same manner as in Example/1 using an autoclave of P d/S i 02
was separated by mouth C2. As a result of analyzing the obtained reaction mixture, the reaction rate of i-butylamine was 100%, and n
It was found that -butyl isocyanate was produced at a yield of /θ, and (p-chlorophenyl)methyl carbamate was produced at a yield of /4.

This mixture was introduced from the top of a vertical tubular decomposition reaction distiller (diameter 2 side, length 7 m, filled with Dixon backing) maintained at 210° C. at a flow rate of /θ0f/hour. From the bottom of the reaction distillation tube, nitrogen gas preheated to 10℃
It was introduced at t/h. Also, at the top of the reaction distillation tube /
A partial condenser maintained at 4tθ°C was installed. The n-butyl isocyanate produced as the reaction progressed was collected in gaseous form from the upper part of the partial condenser and collected in liquid form through a water-cooled condenser. What is the yield of lobethyl isocyanate based on the lobethylamine used? He was in charge.

Example 7.2 Chlohexylamine Cojmmo1. α-Naphthol/
4F, Rh/C/, J with 71 rhodium supported on activated carbon
: f, tetraethyl ammonium iocide/mmol
As a result of carrying out the same carbonylation reaction as in Example 1 using
Obtained in poor yield.

After Rh/C was separated from the reaction mixture by mouth filtration, cyclohexyl isocyanate was separated by distillation in three Roof flasks (two people) together with thermal decomposition reaction and distillation using the following method.

This flask was equipped with a nitrogen inlet extending below the liquid level, a thermometer, and a partial condenser, and the flask was maintained at 20°C by the external temperature.

Also, the partial condenser is /♂! It was kept at ℃. /♂0℃l
While introducing two preheated nitrogen at 2017 hours, the cyclohexyl isocyanate contained in the reaction mixture and the cyclohexyl isocyanate produced by the thermal decomposition are co-coupled with a small amount of α-naphthol vapor in the C: partial condenser. It was collected in gaseous form from the upper part and recovered in liquid form by cooling. The yield of cyclohexyl isocyanate is 6
It was 6chi.

A method similar to the carbonylation step of Example/3 (from 2, hexamethelene diisocyanate was produced in a yield of 2/min, /-
Carbonylation reaction products were obtained with a yield of 12% for isocyanate-6-phuninoxycarpamoyl-hechitin and a yield of 6% for tg-diphenoxycarbamoyl-hechitin. The weight f1 composition of this reaction mixture is hexamethylene diisocyaner)/0.7,/-isocyanate-6-phenoxycarbamoyl-hequinanoco. 61. /
, 7.7 diphenoxycarpamoyl hequinane,
Phenol/[1. This mixture /60'l:
TTTTOY7
It was introduced in one step. The part of this apparatus below the inlet was kept at 210°C', and the part above the inlet was kept at 0°C. From the upper part of this device, phenol produced by thermal decomposition of the phenol and valethane compounds contained in the feed liquid was recovered almost quantitatively. It was found that the liquid substance obtained from the lower part contained 6 hexamethylene diisocyanate.

〔effect〕

It has been revealed that aliphatic inocyanates can be produced in high yield and at low cost from aliphatic 7th-class amines by the method of the present invention.

Claims (1)

[Claims] 1. A method for producing an aliphatic isocyanate from an aliphatic primary amine, comprising: (a) molecular oxygen; i) an aromatic hydroxyl compound having a pKa of 11 or less; and ii) palladium or rhodium and the like. and at least one compound selected from compounds containing iodine or bromine. (b) a carbonylation step of obtaining a carbonylation reaction product having an aliphatic isocyanate as a main product and a urethane compound as a by-product by reacting with carbon monoxide in a temperature range of 240°C; The carbonylation reaction product was 100 to 3
By treating at a temperature of 00°C, the urethane compound in the carbonylation reaction product is decomposed into aliphatic isocyanate and aromatic hydroxyl compound, while the low boiling point component of aliphatic isocyanate or aromatic hydroxyl compound is Process for producing aliphatic isocyanate 2, characterized in that the aliphatic isocyanate and the aromatic hydroxyl compound are separately recovered by carrying out a separation step including thermal decomposition reaction distillation to extract the aliphatic isocyanate in a gaseous state.Aromatic hydroxyl When the compound is combined with the target aliphatic isocyanate under pyrolysis reaction distillation conditions at least 10
Method 3 according to claim 1, which has a boiling point difference of ℃.Claim 3, wherein the catalyst in the carbonylation step is a combination of palladium or a compound containing palladium, and iodine or a compound containing iodine. Scope 4 Method according to claim 1, wherein the aliphatic primary amine is a diamine Method 5 according to claim 1, wherein the diamine is hexamethylene diamine, and the aliphatic isocyanate to be produced is hexamethylene diisocyanate. The method according to claim 4, which is