METHOD FOR PRODUCING NITRILE

Abstract

The present invention provides a method of producing a nitrile from a primary amide, characterized in that the primary amide is subjected to a dehydration reaction in a supercritical fluid in the presence of an acid catalyst. The present invention achieves the object of reducing the corrosion of a reactor and the thermal decomposition of raw materials, as well as provides the effect of improving the reaction rate and nitrile selectivity.

Claims

1-6. (canceled)

7. A method of producing a nitrile, the method comprising subjecting a primary amide to a dehydration reaction in a supercritical fluid in the presence of a solid acid catalyst.

8. The method according to claim 7, wherein said primary amide is a primary amide comprising one or two primary amide groups.

9. The method according to claim 7, wherein said primary amide is a saturated alkylamide, an unsaturated alkylamide, or an amide comprising an aromatic ring and/or a heterocyclic ring.

10. The method according to claim 7, wherein said supercritical fluid is a supercritical fluid of one or more substances selected from the group consisting of carbon dioxide, an alcohol compound, an ether compound and a hydrocarbon compound.

11. The method according to claim 7, wherein said supercritical fluid is a supercritical fluid of one or more substances selected from the group consisting of carbon dioxide, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, tert-amyl alcohol, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, pentane, hexane and benzene.

12. The method according to claim 7, wherein said solid acid catalyst is selected from the group consisting of a metal oxide, a metal sulfide, a zeolite, a clay, an acidic ion exchange resin, a heteropoly acid, a solid phosphoric acid and hydroxyapatite.

Description

DESCRIPTION OF EMBODIMENTS

[0025] The present invention will now be described in further detail.

[Primary Amide]

[0026] In the present invention, the term primary amide refers to an organic compound containing one or more primary amide groups (CONH.sub.2). Any primary amide can be used as a raw material in the method of producing a nitrile according to the present invention, without particular limitations.

[0027] The number of primary amide groups contained in the primary amide is not particularly limited. However, a primary amide containing one or two primary amide groups can be preferably used.

[0028] The primary amide to be used in the present invention is not particularly limited. However, a saturated alkylamide, an unsaturated alkylamide, or an amide containing an aromatic ring and/or a heterocyclic ring can be preferably used.

[0029] The term saturated alkylamide refers to a primary amide which does not contain an unsaturated alkyl group, an aromatic ring and a heterocyclic ring, and which contains a saturated alkyl group having an arbitrary number of carbon atoms and having an arbitrary functional group(s). Examples of the saturated alkylamide include acetamide, propanamide, butylamide, valeramide, hexanamide, cyclohexanamide, malonamide, succinamide, glutaramide, adipamide, suberonamide, 1,3-cyclohexanediamide and 1,4-cyclohexanediamide.

[0030] The term unsaturated alkylamide refers to a primary amide which does not contain an aromatic ring and a heterocyclic ring, and which contains an unsaturated alkyl group having an arbitrary number of carbon atoms and having an arbitrary functional group(s). Examples of the unsaturated alkylamide include acrylamide, methacrylamide, butenamide, hexenamide, 2-hexene-1,6-diamide, 3-hexene-1,6-diamide and 2,4-hexadiene-1,6-diamide.

[0031] The term amide containing an aromatic ring and/or a heterocyclic ring refers to a primary amide containing an aromatic ring and/or a heterocyclic ring, and having an arbitrary number of carbon atoms and having an arbitrary functional group(s). Examples of the amide containing an aromatic ring and/or a heterocyclic ring include benzamide, 4-aminobenzamide, 2-hydroxybenzamide, isophthalamide, terephthalamide, cinnamyl amide, nicotinamide and isonicotinamide.

[0032] The term arbitrary functional group as used herein refers to an alkyl group, a carbonyl group (CO), a hydroxy group (OH), an aldehyde group (CHO), a carboxy group (COOH), an ether bond (O), an ester bond (COO), an amino group (NH.sub.2), a nitro group (NO.sub.2), a cyano group (CN), a secondary amide group (CONHR.sub.1: wherein R.sub.1 represents an arbitrary alkyl group), a tertiary amide group (CONR.sub.1R.sub.2: wherein each of R.sub.1 and R.sub.2 represents an arbitrary alkyl group), a sulfo group (SO.sub.3H) or a halogen atom (F, Cl, Br, I).

[0033] Primary amides can be produced chemically and/or biologically, using various types of carbon sources, such as crude oil, charcoal, natural gases, biomass, exhaust gases and plastic products, as raw materials, and any of the thus produced primary amides can be used in the present invention.

[0034] In particular, as shown in the following scheme 1, a primary amide is industrially synthesized by heating a carboxylic acid (RCOOH) and ammonia to produce a carboxylic acid ammonium salt, followed by the dehydration of the carboxylic acid ammonium salt (disclosed, for example, in JP 2016-513119 A). Alternatively, as shown in scheme 2, a primary amide is industrially synthesized also by the ammonolysis of a carboxylic acid ester (RCOOR), (disclosed, for example, in JP 10-195035 A).

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[0035] In the present invention, a primary amide produced from a carboxylic acid or a carboxylic acid ester as described above can also be used as a raw material, to produce a corresponding nitrile.

[Nitrile]

[0036] The nitrile to be produced by the present invention is an organic compound containing a cyano group (CN), and produced by dehydrating some or all of the primary amide groups contained in the above described primary amide.

[Acid Catalyst]

[0037] The dehydration reaction of a primary amide is accelerated in the presence of an acid catalyst. In the present invention, the acid catalyst may be an acid catalyst which exhibits either a Bronsted acidity or a Lewis acidity. The acid catalyst is, for example, an inorganic acid, an organic acid or a solid acid catalyst, and a solid acid catalyst is preferably used in the present invention.

[0038] Examples of the inorganic acid which can be used in the present invention include: mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid and boric acid; halides containing one or more metal elements selected from the group consisting of Sn, Ga, In, Sc, Fe, Al, B, Zn, Ti, Zr, Sb and Cd; sulfate salts; hydrochloride salts; and nitrate salts.

[0039] Examples of the organic acid which can be used in the present invention include: organic sulfonic acids such as methanesulfonic acid, paratoluenesulfonic acid and paraaminobenzenesulfonic acid; and carboxylic acids such as formic acid, acetic acid and fluoroacetic acid.

[0040] The term solid acid catalyst refers to an acid catalyst which is a solid having an acidic active site on the surface thereof. The solid acid catalyst which can be used in the present invention may be, for example, a metal oxide, a metal sulfide, a zeolite, a clay, an acidic ion exchange resin, a heteropoly acid, a solid phosphoric acid or hydroxyapatite.

[0041] Examples of the metal oxide which serves as the solid acid catalyst include oxides containing one or more metal elements selected from the group consisting of Sc, Y, Ce, Ti, Zr, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Zn, Cd, Al, Ga, In, Si, Ge, Sn and Pb. More specific examples thereof include scandium oxide (Sc.sub.203), cerium oxide (Ce.sub.02), anatase-type titanium oxide (A-TiO.sub.2), rutile-type titanium oxide (RTiO.sub.2), zirconium oxide (ZrO.sub.2), vanadium oxide (V.sub.2O5), niobium oxide (Nb.sub.2O.sub.5), tantalum oxide (Ta.sub.2O.sub.5), chromium oxide (Cr.sub.2O.sub.3), molybdenum oxide (MoO.sub.3), tungsten oxide (WO.sub.3), manganese oxide (MnO.sub.2), iron oxides (Fe.sub.2O.sub.3, Fe.sub.3O.sub.4), zinc oxide (ZnO), aluminum oxide (Al.sub.2O.sub.3), gallium oxide (Ga.sub.2O.sub.3), indium oxide (In.sub.2O.sub.3), silicon dioxide (SiO.sub.2), germanium oxide (GeO.sub.2), tin oxide (SnO.sub.2) and lead oxide (PbO).

[0042] Examples of the zeolite which serves as the solid acid catalyst include zeolites to which structural codes composed of three alphabet letters are assigned in the database of International Zeolite Association. Specific examples thereof include zeolites to which structural codes such as LTA, FER, MWW, MFI, MOR, LTL, FAU, BEA, CHA and CON are assigned.

[0043] Examples of the clay which serves as the solid acid catalyst include kaolin, montmorillonite, bentonite, saponite and acid earth.

[0044] Examples of the acidic ion exchange resin which serves as the solid acid catalyst include styrene-based sulfonic acid-type ion exchange resins and phenol-based sulfonic acid-type ion exchange resins. Specific examples thereof include: DIAION manufactured by Mitsubishi Chemical Corporation; Lewatit manufactured by Lanxess Inc.; Amberlite and Amberlyst manufactured by Rohm and Haas Company; and DOWEX manufactured by Dow Inc.

[0045] The heteropoly acid is an acid catalyst composed of a hetero element such as Si, P or As, a poly element such as Mo, W or V, and oxygen. Examples of the heteropoly acid which serves as the solid acid catalyst include phosphotungstic acid, silicotungstic acid, phosphomolybdic acid and silicomolybdic acid.

[0046] Examples of the solid phosphoric acid which serves as the solid acid catalyst include phosphate salts containing one or more metal elements selected from the group consisting of Si, B, Al, Zr, Zn, Ti and Fe. More specific examples thereof include silicon phosphate, boron phosphate, aluminum phosphate, zirconium phosphate, zinc phosphate, titanium phosphate and iron phosphate.

[0047] As the acid catalyst, two or more kinds of acid catalysts arbitrarily selected from the above described acid catalysts can be mixed and used as a mixture, or alternatively, two or more kinds of acid catalysts can be chemically compounded and used as a composite. For example, silicon dioxide supporting phosphoric acid, silicon dioxide supporting a metal halide, silica-alumina (SiO.sub.2-Al.sub.2O.sub.3) which is a composite of silicon dioxide and aluminum oxide, and the like, are also included in the solid acid catalysts which can be used in the present invention.

[Supercritical Fluid]

[0048] The term supercritical fluid refers to a substance at a temperature and a pressure equal to or higher than the critical point (supercritical state). In the present invention, the substance as the original material of the supercritical fluid is not particularly limited, and a supercritical fluid of any substance can be used as a reaction field for the dehydration reaction of the primary amide to be used in the present invention, as long as the effects of the present invention are achieved. Further, it is possible to use a supercritical fluid of one kind of substance, or a supercritical fluid of a mixture of two or more kinds of different substances, as the supercritical fluid to be used in the present invention.

[0049] The substance which can be used as the supercritical fluid may be, for example, ammonia, carbon monoxide, carbon dioxide, water, an alcohol compound, an ether compound, an ester compound, a hydrocarbon compound or an organochlorine compound. The substance may also be a mixture of two or more kinds of these substances.

[0050] Examples of the alcohol compound include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, tert-amyl alcohol and cyclohexanol.

[0051] Examples of the ether compound include dimethyl ether, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane and cyclopentyl methyl ether.

[0052] Examples of the ester compound include methyl formate, ethyl formate, methyl acetate, ethyl acetate, n-propyl acetate and n-butyl acetate.

[0053] Examples of the hydrocarbon compound include ethane, ethylene, propane, propylene, butane, isobutane, pentane, hexane, heptane, octane, decane, cycloheptane, cyclohexane, benzene, toluene and xylene.

[0054] Examples of the organochlorine compound include carbon tetrachloride, dichloromethane and chloroform.

[0055] Among these, preferably used are: alcohol compounds such as carbon dioxide, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, tert-amyl alcohol, and cyclohexanol; ether compounds such as dimethyl ether, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dibutyl ether, 1,2-dimethoxyethane, diglyme, tetrahydrofuran, 1,4-dioxane and cyclopentyl methyl ether; and hydrocarbon compounds such as ethane, ethylene, propane, propylene, butane, isobutane, pentane, hexane, heptane, octane, decane, cycloheptane, cyclohexane, benzene, toluene and xylene. More preferably used are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, tert-amyl alcohol, diethyl ether, methyl-tert-butyl ether, diisopropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, pentane, hexane and benzene.

[0056] The critical temperature and the critical pressure of substances are described in CRC Handbook of Chemistry and Physics, The 84th edition, CRC Press, 2003-2004, page 1023 to 1038. The critical temperature and the critical pressure of typical substances are shown in Table 1.

TABLE-US-00001 TABLE 1 Critical temperature and critical pressure of substances Critical temperature Critical pressure Substance T.sub.c ( C.) P.sub.c (MPa) Ammonia 132 11.4 Carbon monoxide 140 3.5 Carbon dioxide 31 7.4 Ethane 32 4.9 Propane 97 4.2 Isobutane 135 3.6 Water 374 22.1 Methanol 240 8.1 Ethanol 241 6.1 1-Propanol 264 5.2 2-Propanol 235 4.8 1-Butanol 290 4.4 2-Butanol 263 4.2 Isobutanol 275 4.3 Tert-butanol 233 4.0 Tert-amyl alcohol 271 3.7 Diethyl ether 194 3.6 Methyl-tert-butyl ether 224 3.4 Diisopropyl ether 227 2.8 1,2-Dimethoxyethane 267 3.9 Tetrahydrofuran 267 5.2 Pentane 197 3.4 Hexane 234 3.0 Benzene 289 4.9

[Reaction Method]

[0057] The production method according to the present invention can be carried out in a reaction method using any of a batch tank reactor, a semi-batch tank reactor, a continuous tank reactor and a continuous tubular reactor.

[0058] In the case of carrying out the reaction using a solid acid catalyst, the reaction can be carried out by any of a suspended bed system, a fixed bed system, a moving bed system and a fluidized bed system.

[Reaction Temperature]

[0059] The reaction temperature in the dehydration reaction of a primary amide is not particularly limited, as long as it is equal to or higher than the critical temperature of the substance to be used as the supercritical fluid. The reaction temperature is preferably 300 C. or lower, because it allows for reducing the thermal decomposition of the primary amide as the raw material.

[Reaction Pressure]

[0060] The reaction pressure in the dehydration reaction is not particularly limited, as long as it is equal to or higher than the critical pressure of the substance to be used as the supercritical fluid.

[0061] In any of the cases of the batch tank reactor, the semi-batch tank reactor, the continuous tank reactor and the continuous tubular reactor, the pressure inside the reactor can be increased by using an arbitrary pump. For example, a pump for feeding the raw material to the reactor can be used to apply a pressure from the raw material feed port side of the reactor. The pressure inside the reactor can be controlled by providing a back pressure valve to the discharge side of the reactor.

[0062] In the case of using a tank reactor, when a sufficient amount of a substance that is a solid or a liquid in a standard state (25 C., atmospheric pressure) is introduced into the reactor, and the reactor is heated in a non-open state, the vapor pressure of the substance corresponding to the temperature is applied to the reactor. Accordingly, in cases where the temperature of the reactor is adjusted to equal to or higher than the critical temperature of the substance, the pressure inside the reactor is naturally increased to equal to or higher than the critical pressure. In this case, there is no need to apply a pressure from the outside in order to achieve the critical pressure. It is noted that the sufficient amount as used herein refers to the amount of a substance which is sufficient enough so that all of the substance does not vaporize when the critical temperature is reached.

[0063] The substance to be used as the supercritical fluid in the reactor can be controlled to a supercritical state, for example, by a method in which a sufficient amount of a substance that is a solid or a liquid in a standard state (25 C., atmospheric pressure) is introduced into the reactor, and the reactor is heated in a non-open state to a temperature equal to or higher than the critical temperature of the substance, as described above, thereby controlling the interior of the reactor to a temperature equal to or higher than the critical temperature and to a pressure equal to or higher than the critical pressure. A method can also be used in which the pressure inside the reactor is increased to a pressure equal to or higher than the critical pressure of the substance, using a pump or the like, and then the temperature inside the reactor is increased to a temperature equal to or higher than the critical temperature of the substance. Further, a method can also be used in which the temperature inside the reactor is increased to a temperature equal to or higher than the critical temperature, and then the internal pressure of the reactor is increased to a pressure equal to or higher than the critical pressure, using a pump or the like.

[Atmosphere]

[0064] In the reactor for carrying out the dehydration reaction of a primary amide, a substance that is a gas in a standard state (25 C., atmospheric pressure), such as nitrogen, helium, argon, oxygen, hydrogen, ammonia or the like, may coexist with the supercritical fluid. These gases are capable of forming a good mixed state with the supercritical fluid in the reactor. Above all, coexistence of ammonia is preferred, since ammonia is expected to be capable of reducing the generation of a carboxylic acid due to the deamidation of the primary amide. Further, in order to reduce the reverse reaction to the primary amide due to the hydration of the produced nitrile, it is preferred that water vapor is absent or present in a minimum amount.

[Recovery of Nitrile]

[0065] The nitrile produced by the method of producing a nitrile according to the present invention can be recovered by carrying out general separation and purification operations, such as filtration, extraction, distillation, crystallization and recrystallization, after the completion of the reaction.

[Production of Hexamethylenediamine]The method of producing a nitrile according to the present invention is capable of producing adiponitrile, when adipamide is used as the primary amide. The resulting adiponitrile can be hydrogenated by a known method (such as one disclosed in JP 2000-508305 A) to produce hexamethylenediamine, which is the raw material of polyamide 6,6.

EXAMPLES

[0066] The present invention will now be described in further detail with reference to Examples. It is noted, however, that the present invention is in no way limited to the following Examples. The reaction results in Examples and Comparative Examples are defined by the following equations.

Proportion of dehydrated primary amide groups (%)=(amount of dehydrated primary amide groups/total amount of primary amide groups in raw material)100.

Nitrile selectivity (%)=amount of nitrile produced (mol)/(amount of raw material amide (mol)amount of unreacted amide (mol))100.

[0067] The resulting reaction solution and an aqueous solution of a concentrate of the reaction solution were analyzed by gas chromatography (GC) and high-speed liquid chromatography (HPLC), respectively. The quantification of the resulting product was carried out based on an absolute calibration curve prepared using a reference standard. The quantitative analysis of each nitrile was mainly carried out by GC, and the quantitative analysis of each amide was mainly carried out by HPLC. The analysis conditions for GC and HPLC are shown below.

[GC Analysis Conditions]

[0068] GC apparatus: GC2010 plus (manufactured by Shimadzu Corporation) Column: InertCap for amines; length: 30 m; inner diameter: 0.32 mm (manufactured by GL Sciences Inc.) [0069] Carrier gas: helium; linear velocity: constant (40.0 cm/sec) [0070] Vaporization chamber temperature: 250 C. [0071] Detector temperature: 250 C. [0072] Column oven temperature: 100 C..fwdarw.(10 C./min).fwdarw.230 C., 10 min (total: 23 min) [0073] Detector: FID

[HPLC Analysis Conditions]

[0074] HPLC apparatus: Prominence (manufactured by Shimadzu Corporation) [0075] Column: Synergi hydro-RP (manufactured by Phenomenex Inc.); length: 250 mm; inner diameter: 4.60 mm; particle size: 4 m [0076] Mobile phase: 0.1% by weight aqueous phosphoric acid solution/acetonitrile=95/5 (volume ratio) [0077] Flow velocity: 1.0 mL/min [0078] Detector: UV (210 nm) [0079] Column temperature: 40 C.

Example 1

Production of Nitrile from Adipamide

[0080] Into a stainless steel autoclave (manufactured by Taiatsu Techno Corporation) having a capacity of 0.1 L, 0.144 g of adipamide (manufactured by Tokyo Chemical Industry Co., Ltd.), 50 mL of tert-butanol (manufactured by Wako Pure Chemical Industries, Ltd.), and 0.05 g of an -iron oxide (-Fe.sub.2O; manufactured by Wako Pure Chemical Industries, Ltd.) as a catalyst were introduced. The interior of the autoclave was adjusted to 30 C., and the interior of the autoclave was purged with nitrogen while stirring at a stirring rate of 500 rpm. Subsequently, ammonia gas was added such that the partial pressure of ammonia gas inside the autoclave was adjusted to 0.18 MPa, and the autoclave was maintained for 30 minutes thereafter. Nitrogen was then added to the autoclave, while continuing the stirring, such that the partial pressure of nitrogen inside the autoclave was adjusted to 0.32 MPa (total pressure (gauge pressure): 0.50 MPa). Thereafter, the temperature inside the autoclave was raised to 235 C. The gauge pressure at 235 C. was 4.8 MPa. The autoclave was maintained for one hour at 235 C., and then allowed to cool to room temperature. After releasing the gas in the autoclave so as to reduce the pressure inside the autoclave to normal pressure, the reaction solution was recovered. The catalyst was removed by filtration, and the resulting supernatant was analyzed by GC. Further, the supernatant was concentrated by a rotatory evaporator (manufactured by Tokyo Rikakikai Co., Ltd.) to obtain a concentrate, an aqueous solution of the concentrate was prepared, and then analyzed by HPLC. The results are shown in Table 2.

Comparative Example 1

[0081] The reaction was carried out in the same manner as in Example 1, except that no catalyst was used. The results are shown in Table 2.

Comparative Example 2

[0082] The reaction was carried out in the same manner as in Example 1, except that the temperature inside the autoclave was adjusted to 225 C. The results are shown in Table 2.

Comparative Example 3

[0083] The reaction was carried out in the same manner as in Example 1, except that the temperature inside the autoclave was adjusted to 230 C. The results are shown in Table 2.

Example 2

[0084] The reaction was carried out in the same manner as in Example 1, except that 2-propanol (manufactured by Nacalai Tesque Inc.) was used instead of tert-butanol, and that the temperature inside the autoclave was adjusted to 237 C. The results are shown in Table 2.

Example 3

[0085] The reaction was carried out in the same manner as in Example 2, except that the temperature inside the autoclave was adjusted to 240 C. The results are shown in Table 2.

Comparative Example 4

[0086] The reaction was carried out in the same manner as in Example 2, except that the temperature inside the autoclave was adjusted to 230 C. The results are shown in Table 2.

Comparative Example 5

[0087] The reaction was carried out in the same manner as in Example 2, except that the temperature inside the autoclave was adjusted to 232 C. The results are shown in Table 2.

Example 4

[0088] The reaction was carried out in the same manner as in Example 1, except that diisopropyl ether was used instead of tert-butanol, and that the temperature inside the autoclave was adjusted to 230 C. The results are shown in Table 2.

Comparative Example 6

[0089] The reaction was carried out in the same manner as in Example 4, except that the temperature inside the autoclave was adjusted to 225 C. The results are shown in Table 2.

TABLE-US-00002 TABLE 2 Production of nitrile from adipamide Reactor Proportion of Substance Reaction internal dehydrated primary Nitrile Raw used as temperature pressure amide groups selectivity material Catalyst reaction field ( C.) (MPa) State (%) (%) Example 1 adipamide Fe.sub.2O.sub.3 tert-butanol 235 4.8 Supercritical 13.8 80.7 Comparative adipamide None tert-butanol 235 4.8 Supercritical 0.5 9.8 Example 1 Comparative adipamide Fe.sub.2O.sub.3 tert-butanol 225 3.9 Non-supercritical 0.6 20.1 Example 2 Comparative adipamide Fe.sub.2O.sub.3 tert-butanol 230 4.3 Non-supercritical 0.9 24.2 Example 3 Example 2 adipamide Fe.sub.2O.sub.3 2-propanol 237 5.6 Supercritical 52.2 94.4 Example 3 adipamide Fe.sub.2O.sub.3 2-propanol 240 6.0 Supercritical 56.8 86.7 Comparative adipamide Fe.sub.2O.sub.3 2-propanol 230 4.4 Non-supercritical 2.5 32.0 Example 4 Comparative adipamide Fe.sub.2O.sub.3 2-propanol 232 5.0 Non-supercritical 4.0 55.0 Example 5 Example 4 adipamide Fe.sub.2O.sub.3 diisopropyl 230 3.0 Supercritical 19.8 81.2 ether Comparative adipamide Fe.sub.2O.sub.3 diisopropyl 225 2.6 Non-supercritical 13.0 60.2 Example 6 ether

(Example 5

Production of Benzonitrile from Benzamide

[0090] The reaction was carried out in the same manner as in Example 1, except that 0.121 g of benzamide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of adipamide. After adding 2-propanol to the recovered reaction solution and stirring the mixture at room temperature, the catalyst was removed by centrifugation, and the supernatant was analyzed by GC. The results are shown in Table 3.

Example 6

Production of Nicotinonitrile from Nicotinamide

[0091] The reaction was carried out in the same manner as in Example 1, except that 0.122 g of nicotinamide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of adipamide. The results are shown in Table 3.

Example 7

Production of Nitrile from Terephthalamide

[0092] The reaction was carried out in the same manner as in Example 1, except that 0.164 g of terephthalamide (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of adipamide. The recovered reaction solution was concentrated by a rotatory evaporator to obtain a concentrate, and a solution obtained by dissolving the concentrate in dimethyl sulfoxide (DMSO: manufactured by Wako Pure Chemical Industries, Ltd.) was analyzed by HPLC. The results are shown in Table 3.

Example 8

Production of Benzonitrile from Benzamide

[0093] The reaction was carried out in the same manner as in Example 5, except that hexane (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of tert-butanol, and that the reaction temperature was adjusted to 237 C. The results are shown in Table 3.

Example 9

Production of Acrylonitrile from Acrylamide

[0094] The reaction was carried out in the same manner as in Example 5, except that acrylamide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of benzamide. The results are shown in Table 3.

Example 10

Production of Hexanenitrile from Hexanamide

[0095] The reaction was carried out in the same manner as in Example 1, except that 0.115 g of hexaneamide (manufactured by Sigma-Aldrich Co. LLC.) was used instead of adipamide. The catalyst was removed by centrifugation, and the supernatant was analyzed by GC. The results are shown in Table 3.

Examples 11 to 17

Production of Hexanenitrile from Hexanamide

[0096] In each of the Examples, the reaction was carried out in the same manner as in Example 10, except that, instead of using the -iron oxide (Fe.sub.2O.sub.3), niobium oxide (Nb.sub.2O.sub.5; manufactured by Wako Pure Chemical Industries, Ltd.), indium oxide (In.sub.2O.sub.3; manufactured by Wako Pure Chemical Industries, Ltd.), an MFI zeolite (ZSM-5; manufactured by JGC C&C), a FAU zeolite (JRC-Z-HY; manufactured by JGC C&C, provided by Reference Catalyst Committee, Catalysis Society of Japan), montmorillonite (manufactured by Sigma-Aldrich Co. LLC.), aluminum phosphate (manufactured by Sigma-Aldrich Co. LLC.) or silica-alumina (manufactured by JGC C&C) was used. The results are shown in Table 3.

TABLE-US-00003 TABLE 3 Production of nitriles from various kinds of primary amides Reactor Proportion of Substance Reaction internal dehydrated primary Nitrile used as temperature pressure amide groups selectivity Raw material Catalyst reaction field ( C.) (MPa) State (%) (%) Example 5 benzamide Fe.sub.2O.sub.3 tert-butanol 235 5.4 Supercritical 16.5 78.0 Example 6 nicotinamide Fe.sub.2O.sub.3 tert-butanol 235 5.1 Supercritical 15.7 81.6 Example 7 terephthal amide Fe.sub.2O.sub.3 tert-butanol 235 5.6 Supercritical 8.9 >99.9 Example 8 benzamide Fe.sub.2O.sub.3 hexane 237 3.2 Supercritical 41.3 90.6 Example 9 acrylamide Fe.sub.2O.sub.3 hexane 237 3.2 Supercritical 13.1 90.1 Example 10 hexanamide Fe.sub.2O.sub.3 tert-butanol 235 6.1 Supercritical 20.4 79.7 Example 11 hexanamide Nb.sub.2O.sub.5 tert-butanol 235 5.9 Supercritical 19.5 82.3 Example 12 hexanamide In.sub.2O.sub.3 tert-butanol 235 5.9 Supercritical 22.2 83.4 Example 13 hexanamide MFI zeolite tert-butanol 235 5.9 Supercritical 13.2 75.4 Example 14 hexanamide FAU zeolite tert-butanol 235 5.8 Supercritical 11.5 72.9 Example 15 hexanamide Montmorillonite tert-butanol 235 5.7 Supercritical 26.0 80.2 Example 16 hexanamide Aluminum tert-butanol 235 5.8 Supercritical 17.4 70.5 phosphate Example 17 hexanamide Silica-alumina tert-butanol 235 5.9 Supercritical 12.5 74.8

[0097] In a supercritical fluid, the proportion of dehydrated primary amide groups is markedly high, and thus it can be seen that the reaction rate of the dehydration reaction has been improved. Further, it can be seen that the nitrile selectivity is markedly high in a supercritical fluid. Therefore, the results of Examples 1 to 4 and

[0098] Comparative Examples 1 to 6 have shown that, by carrying the dehydration reaction of a primary amide out in a supercritical fluid in the presence of an acid catalyst, it is possible to improve the reaction rate and to produce a nitrile at a high nitrile selectivity.

[0099] Further, the results of Examples 5 to 17 have shown that the present invention can be used for the production of nitriles from various kinds of primary amides, in various kinds of supercritical fluids, and in the presence of various kinds of acid catalysts.

INDUSTRIAL APPLICABILITY

[0100] The method of producing a nitrile according to the present invention provides an excellent reaction rate and nitrile selectivity, and the nitriles obtained by the present method can be suitably used in a number of applications, such as solvents, raw materials for pharmaceuticals, raw materials for agricultural chemicals, metal surface treatment agents, antioxidants and polymer raw materials.