PREPARATION METHOD OF ALDEHYDE COMPOUND 5 TECHNICAL FIELD [0001] The present invention relates to a preparation method of an aldehyde compound, a preparation method of an amine compound and a preparation method of an isocyanate compound using the aldehyde 10 compound obtained by the preparation method. BACKGROUND ART [0002] As a manufacturing method of an aldehyde compound using 15 norbornene compound, for example, methods described in Patent Documents 1 to 3 are known. [0003] Patent Documents 1 to 3 disclose methods for manufacturing formyl cyan norbornene by hydroformylating cyan norbornene using a 20 mixed H2/CO gas in the presence of a catalyst. Patent Documents 1 and 2 disclose an example using a metal compound as a catalyst. Moreover, since it is possible to obtain a target compound with high selectivity, and it is possible to suppress the reaction pressure to be low, a rhodium complex is preferably used as the catalyst. 25 [0004] Patent Document 1 describes that the catalyst may be used at 0.1% by weight to 10 % by weight with respect to cyan norbornene. 2 Patent Document 2 describes that with the catalyst concentration of 0.5 mmol/1 to 10 mmol/1, triarylphosphine can be used in a range of 3 moles to 300 moles with respect to 1 mole of rhodium. [0005] 5 Patent Document 4 discloses a method of hydroformylating an olefin-based compound using a mixed H2/CO gas in the presence of a transition metal catalyst and a trivalent phosphorus compound. Furthermore, it is described that as the content of the metal catalyst, a free metal content is 10 ppm to 1,000 ppm based on the weight or 10 volume of the catalyst composition. Patent Document 5 describes a metal ligand complex catalyst, and exemplifies rhodium as a metal and an organic phosphorus ligand as a ligand. In addition, it is described that the amount of these used, in a case of calculating as a free metal, is a metal concentration 15 in a range of about 1 ppm to 10,000 ppm, and a molar ratio of ligand:metal is 1:1 to 200:1. In addition, Patent Documents 6 and 7 disclose a method of preparing an aldehyde compound by hydroformylating a linear olefin compound. 20 [0006] In Examples of Patent Document 6, an example of hydroformylating 7-octenal in the presence of a rhodium catalyst and bisphosphite is described. In addition, it is described that about 3 ppmmol of rhodium is used with respect to 1 mole of 7-octenal, and rhodium 25 atoms/phosphorus atoms is 1/20 as a molar ratio. On the other hand, in paragraph 0084 of Patent Document 6, it is described that 2 moles to 1, 000 moles in terms of phosphorus atom is preferable with respect 3 to 1 mole of a metal, and in a case of exceeding 1,000 moles, the reaction rate tends to be extremely low. [0007] In addition, Patent Document 7 describes that in the 5 hydroformylation of the olefin, materials such as a halogenated organic compounds are required to be excluded from the reaction, however there is no description regarding the amounts. RELATED DOCUMENT 10 PATENT DOCUMENT [0008] [Patent Document 1] Japanese Laid-open Patent Publication No. 57-193438 [Patent Document 2] Japanese Laid-open Patent Publication No. 15 60-72844 [Patent Document 3] US Patent No. 3,143,570 [Patent Document 4] Japanese Translation of PCT International Application No. 2010-538818 [Patent Document 5] Japanese Translation of PCT International 20 Application No. 2003-505438 [Patent Document 6] Japanese Laid-open Patent Publication No. 2008-031125 [Patent Document 7] Japanese Translation of PCT International Application No. 4-502463 25 DISCLOSURE OF THE INVENTION [0009] 4 In recent years, the amount of rare metal used has increased with the development of technology, and depletion of rare metal resources and price rises have become a problem. Therefore, reducing the amount of so-called rare metals used and effective use thereof 5 have been widely sought. [0010] However, it is found that in the hydroformylation reaction of a norbornene compound, for example, cyanonorbornene, when reducing the amount of a metal compound which is a catalyst, a problem in 10 productivity such as decrease in the reaction rate or decrease in the yield due to stopping of the reaction itself occurs. In. industrial production, decrease in the reaction rate causes a problem in connection to the next step, and thus, production cannot be efficiently performed. 15 [0011] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an industrially advantageous method in which the amount of a metal which is an expensive catalyst is reduced, and which can suppress decrease 20 in the reaction rate even in a case where the amount of the metal is reduced when aldehyde is prepared. [0012] As a result of thorough studies of factors decreasing the reaction rate in order to solve the above problems, the present 25 inventor found that when a chlorine portion is present in the reaction system, the reaction rate is decreased. As a result of further studies, the inventor found that it is possible to prepare aldehyde 5 without reducing the reaction rate by controlling the amount of chlorine atoms in the reaction system, and made the present invention. The present invention can be described as follows. [0013] 5 [1] A preparation method of aldehyde compound including a step of reacting a compound represented by the following general formula (al) or (a2) with hydrogen and carbon monoxide in the presence of a metal compound including 0.01 ppmmol to 10 ppmmol of a metal belonging to Groups 8 to 10 v/ith respect to 1 mole of the compound 10 and a phosphorus compound, in which the amount of a chlorine portion in the reaction system in the step -is equal to or less than 1.5 parts by weight with respect to 1 part by weight of the metal belonging to Groups 8 to 10. 15 [0015] (In the formula (al) , X represents a hydrogen atom, a cyano group, an aldehyde group, or a -CH=NR group, and R represents a hydrogen 6 atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group. In the formulas (al) and (a2), n represents 0, 1 or 2.) [0016] [2] The preparation method of an aldehyde compound according 5 to [1], in which the metal compound including a metal belonging to Groups 8 to 10 is a rhodium compound, a cobalt compound, a ruthenium compound, or an iron compound. [3] The preparation method of an aldehyde compound according to [1] or [2], in which the metal compound including the metal 10 belonging to Groups 8 to 10 is a rhodium compound. [0017] [4] The preparation method of an aldehyde compound according to any one of [1] to [3], in which the amount of the metal belonging to Groups 8 to 10 is 1 ppmmol to 5 ppmmol with respect to 1 mole of 15 the compound represented by the general formula (al) or (a2). [5] The preparation method of an aldehyde compound according to any one of [1] to [4], in which the phosphorus compound is a trivalent phosphorus compound. [6] The preparation method of an aldehyde compound according 20 to any one of [1] to [5], in which the compound represented by the general formula (al) is used, and the compound is the compound represented by the following formula (1). [0018] (In the formula (1) , X is the same as that in the general formula (al).) [0019] 5 [7] A preparation method of an amine compound including a step of reacting the aldehyde compound obtained by the preparation method according to any one of [1] to [6] with ammonia, and hydrogen in the presence of a catalyst. [8] A preparation method of an isocyanate compound including 10 a step of reacting the amine compound obtained by the preparation method according to [7] with a carbonylating agent. [0020] Moreover, the "phosphorous compound" in the present invention means a phosphorous compound capable of forming a complex with a metal. 15 In addition, in the present invention, in a case where a material B is used in the amount of 1 * 10"6 moles with respect to 1 mole of a material A, the amount of the material B is indicated as 1 ppmmol. [0021] According to the preparation method of an aldehyde compound of 20 the present invention, even in a case where the amount of metal which is a catalyst is reduced, a decrease in the reaction rate is suppressed, and industrially advantageous preparation of aldehyde can be achieved. Since the preparation method of an amine compound and the preparation 8 method of an isocyanate compound of the present invention include the preparation method of an aldehyde compound as one step, according to the present invention, the effect is exhibited that productivity and yield of the isocyanate compound and the amine compound also are 5 excellent. BRIEF DESCRIPTION OF THE DRAWINGS [0022] The above-described objects, other objects, features, and 10 advantages will be made clearer from the preferred embodiments described below, and the following accompanying drawings. [0023] FIG. 1 is a 1H~NMR chart of the compound obtained in Example 1. FIG. 2 is a XH~NMR chart of the compound obtained in Example 2. 15 FIG. 3 is a 1H~NMR chart of the compound obtained in Example 3. DESCRIPTION OF EMBODIMENTS [0024] Hereinafter, the preparation method of an aldehyde compound of 20 the present embodiment will be described, and the preparation method of an amine compound, and then, the preparation method of an isocyanate compound will be described. [0025] Preparation Method of Aldehyde Compound> 25 The preparation method of an aldehyde compound of the present embodiment includes a step of reacting the compound represented by the following general formula (al) or (a2) with hydrogen and carbon monoxide in the presence of a metal compound including a metal belonging to Groups 8 to 10 and a phosphorus compound, and the amount of chlorine atoms in the reaction system in the step is equal to or less than 1,5 parts by weight with respect to 1 part by weight of the metal belonging to Groups 8 to 10. [0026] 0 )i In the formula (al) , X represents a hydrogen atom, a cyano group, an aldehyde group, or a -CH=NR group, and R represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 20 carbon atoms. As X, a cyano group or an aldehyde group 15 is preferable, and a cyano group is more preferable. In the formulas (al) and (a2), n represents 0, 1, or 2, and 0 or 1 is preferable, and 1 is more preferable. Moreover, the compound represented by the general formula (al) may be an endo compound or an exo compound, and may be a mixture 10 including these in arbitrary proportions. [0029] As the compound represented by the general formula (al), specifically, the following compounds can be exemplified. 5 (1) As the compound having 0 as n, cyclohexene, 4-cyano-l-cyclohexene, 3-cyclohexene-l-carboxyaldehyde, and 4-iminomethyl-l~cyclohexene can be exemplified. (2) As the compound having 1 as n, bicyclo[2.2.1]-2-heptene, bicyclo[2.2.1]~5-heptene-2~carbonitrile, 10 bicyclo[2.2.1]-5~heptene-2-carboxyaldehyde, and bicyclo[2.2.1]-5-hepten-2-yl methaneamine can be exemplified. (3) As the compound having 2 as n, bicyclo[2.2.2]-2-octene, bicyclo[2.2.2]-5-octene-2-carbonitrile, bicyclo[2.2.2]-5-octene~2-carboxyaldehyde, and 15 bicyclo[2.2.2]-5-hepten~2-yl methaneamine can be exemplified. As the compound represented by the general formula (a2), the following compounds can be exemplified. [0030] (1) As the compound having 0 as n, 1,4-cyclohexadiene can be 20 exemplified. (2) As the compound having 1 as n, bicyclo [2. 2 . l]hepta-2, 5-diene can be exemplified. (3) As the compound having 2 as n, bicyclo [2 .2.2] octa-2, 5-diene can be exemplified. 25 [0031] In the present embodiment, the compound represented by the general formula (al) is preferably used, and n is more preferably 11 1. As the compound, specifically, the compound represented by the following general formula (1) can be preferably used. [0032] 5 LUU-5JJ In the formula (1) , X is the same as that in the general formula (al), and a cyano group or an aldehyde group is preferable, and a cyano group is more preferable. Moreover, the compound represented by the general formula (1) 10 may be an endo compound or an exo compound, and may be a mixture including these in arbitrary proportions. The metal compound including a metal belonging to Groups 8 to 10 used in the reaction of the present embodiment is a rhodium compound, a cobalt compound, a ruthenium compound, or an iron compound. 15 [0034] Examples of the rhodium compound include Rh{acac)(CO)2, Rh(acac)3, Rh2(CO)8, Rh4(CO)i2, and Rh6(C0) 16. Examples of the cobalt compound include HCo(CO)3, HCo(C0)4, Co2(CO)8, and HCo3(CO)9. Examples of the ruthenium compound include Ru (CO) 3 (PPh3) 2 and Ru3 (CO) 12. 20 In addition, examples of the iron compound include Fe(CO)5, Fe(C0)4PPh3, and Fe (CO) 4 (PPh3) 2. Moreover, "acac" means acetylacetonato. [0035] 12 The rhodium compound used in the reaction of the present embodiment is not particularly limited as long as it is a compound including monovalent rhodium metal, and rhodium carbonyl catalysts such as dicarbonylacetylacetonato rhodium (Rh(acac) (CO)2) , 5 dodecacarbonyl tetrarhodium {Rh4 (CO) 12) , hexadecacarbonyl hexarhodium (Rh6(CO)i6), and octacarbonyl dirhodium (Rh2(CO)8) can be exemplified. [0036] The phosphorus compound used in the reaction of the present 10 embodiment is not particularly limited as long as it is a trivalent phosphorus compound, and the compound represented by the follov/ing formula is preferably used. (RX)3P (R20)3P 15 In the above formula, R1 and R2 may be the same as or different from each other, and each of R and R represents an alkyl group having 1 to 16 carbon atoms or an aryl group having 6 to 16 carbon atoms which may have a substituent. [0037] 20 As the phosphorus compound, specifically, trivalent phosphorus compounds such as triphenyl phosphite, triphenyl phosphine, trimethyl phosphine, triethyl phosphine, tripropyl phosphine, tri(methyl benzene)phosphine, tri(ethyl benzene)phosphine, 1,2-bis(diphenyl phosphino)ethylene, 1,3-bis(diphenyl 25 phosphino)propane, 2,2-bis(diphenyl phosphino)-1,1-binaphthyl, trimethoxy phosphite, triethoxy phosphite, tripropoxy phosphite, triisopropoxy phosphite, trimethylphenyl phosphite, and 13 tris (2, 4-di~tert-butylphenyl) phosphite can be exemplified. In the present embodiment, triphenyl phosphite is preferably used. [0038] In general, these compounds are synthesized by a reaction of 5 phosphorus trichloride or phosphorus pentachloride v/ith an aromatic compound, an alicyclic compound, or an aliphatic compound which may include a substituent. Accordingly, a chlorine portion such as phosphorus trichloride or phosphorus pentachloride which is a raw material, a chlorine portion such as hydrogen chloride or chlorine 10 which is a by-product, or a chlorine-containing intermediate generated as a by-product in the reaction are mixed into the phosphorus compound. Although it is considered that chlorine atoms present in the reaction system are derived from the phosphorus compound, a chlorine portion included in other raw materials or the like may also 15 be contained therein. [0039] Moreover, in a case where the metal compound including a metal belonging to Groups 8 to 10 does not include a chlorine atom in the structure, and chlorine-containing compounds are not used in the 20 synthesis step as rav/ materials other than the phosphorus compound, it is therefore considered that chlorine atoms in the reaction system are derived from the phosphorus compound. That is, in this case, chlorine atoms of the amount described below are included in the phosphorus compound v/ith respect to 1 part by weight of the metal 25 belonging to Groups 8 to 10. In a case where the amount of the chlorine portion included in the phosphorus compound becomes the above predetermined amount, it 14 is not necessary to reduce the chlorine portion of the phosphorus compound, however, in a case where the amount of the chlorine portion is greater than the above predetermined amount such as a case where the metal compound including a metal belonging to Groups 8 to 10 5 includes a chlorine atom in the structure, it is possible to reduce the amount of chlorine portion included in the phosphorus compound by a method such as topping or an activated carbon treatment. Moreover, the method for reducing the amount of chlorine portion is not limited to these. 10 [0040] In the hydroformylation reaction using these raw materials, the amount of metal belonging to Groups 8 to 10 to be used is 0.01 ppmmol to 10 ppmmol, and preferably 1 ppmmol to 10 ppmmol, and more preferably 1 ppmmol to 5 ppmmol with respect to 1 mole of the compound represented 15 by the formula (al) or (a2) . When the amount is in the above numerical range, it is possible to ensure smooth progress of the reaction without excessively using an expensive catalyst. In addition, the amount of phosphorus compound used is preferably equal to or greater than 100-fold by mole, more preferably 20 100-fold by mole to 10,000-fold by mole with respect to the metal belonging to Groups 8 to 10. Moreover, the above numerical range can be combined arbitrarily. The amount of chlorine atoms in the reaction system is equal to or less than 1.5 parts by v/eight, and preferably equal to or less 25 than 1.2 parts by weight with respect to 1.0 part by v/eight of the metal belonging to Groups 8 to 10 from the viewpoint of the effect of the present invention. Moreover, although the lov/er limit value 15 is not particularly limited, the lower limit value is equal to or greater than 0.1 parts by weight, and preferably equal to or greater than 0.5 parts by weight with respect to 1.0 part by weight of the metal belonging to Groups 8 to 10. When the amount is the lower limit 5 value, the step of reducing the chlorine portion is simple and does not influence productivity, and thus, it is preferable. Moreover, the upper limit value and the lower limit value can be suitably combined. [0041] 10 Synthesis of the aldehyde compound, specifically, can be performed in the following manner. First, a rhodium compound, a phosphorus compound, and a compound represented by the general formula (al) or (a2) which is a raw material are put in a reactor. While supplying hydrogen and a carbon monoxide 15 gas thereto, the mixture is allowed to react at a temperature of 30°C to 120°C and a pressure of 0.1 MPa to 1.0 MPa for 1 hour to 8 hours. Moreover, the hydroformylation reaction can be performed by suitably selecting a homogeneous reaction system configured of only an oil phase or a two-layer reaction system configured of a water layer and 20 an oil layer. Thus, the compound represented by the general formula (al) or (a2) is hydroformylated, whereby an aldehyde compound is synthesized. [0042] Moreover, the hydroformylation reaction can also be performed 25 without a solvent, or can be performed using a substituted or unsubstituted aromatic compound, a substituted or unsubstituted aliphatic hydrocarbon compound, or alcohol, and for example, the 16 hydroformylation reaction can also be performed in a solvent such ,. as toluene, benzene, hexane, octane, acetonitrile, benzonitrile, ethanol, pentanol, or octanol. The hydroformylation reaction in the present embodiment is also excellent in reactivity at a high 5 concentration, and thus, the hydroformylation reaction can be performed without a solvent. As a result, since a step of distilling off a solvent or the like is not required, the step becomes simple, the volume efficiency also is improved, and the production efficiency also is excellent. 10 [0043] The aldehyde compound represented by the following general formula {bl} is synthesized from the compound of the general formula (al) by the preparation method of the present embodiment. The aldehyde compound represented by the following general formula (b2) 15 is synthesized from the compound of the general formula (a2). [0044] 17 [0046] In a case where n is 1 or 2 and X is a group other than a hydrogen atom, the compound represented by the general formula (bl) or (b2) can be obtained as any one of "a compound in which the 2-position 5 and the 5-position are substituted with predetermined groups (hereinafter, referred to as a 2,5~isomer) " and "a compound in which the 2-position and the 6-position are substituted with predetermined groups (hereinafter, referred to as a 2,6-isomer)", or can be obtained as a mixture including these in arbitrary proportions. In addition, 10 each of the 2,5-isomer and the 2, 6-isomer can be obtained as any one of an endo-endo compound, an endo-exo compound, and an exo-exo compound depending on a steric configuration of the substituent, or can be obtained as a mixture including at least two types of these in arbitrary proportions. 15 [0047] Moreover, in a case where n is 0 and X is a group other than a hydrogen atom, the compound represented by the general formula (bl) or (b2). can be obtained as any one of a cis-type and a trans-type, or can also be obtained as a mixture including these in arbitrary 20 proportions. In the general formula (bl) or (b2), X and n are the same as those in the general formula (al) or (a2). In the present embodiment, the compound represented by the general formula (bl) is preferably obtained, and as the compound, 25 the compound represented by the following general formula (2) can be exemplified. [0048] [0049] In the formula (2), X is the same as that in the general formula (1). 5 Moreover, the aldehyde compound represented by the general formula (2) can be obtained as any one of "a compound in which the 2-position of bicyclo[2.2.1]heptane is substituted with a substituent X and the 5-position is substituted with an aldehyde group (hereinafter, referred to as a 2,5~isomer) " and "a compound in which 10 the 2-position is substituted with a substituent X and the 6-position is substituted with an aldehyde group (hereinafter, referred to as a 2,6-isomer)", or can be obtained as a mixture including these in arbitrary proportions. In addition, each of the 2,5-isomer and the 2, 6-isomer can be obtained as any one of an endo-endo compound, an 15 endo-exo compound, and an exo-exo compound depending on a steric configuration of the substituent, or can be obtained as a mixture including at least two types of these in arbitrary proportions. After the hydroformylation reaction is finished, a target aldehyde compound can be obtained by performing a predetermined 20 purification step. [0050] 19 Preparation Method of Amine Compound> The preparation method of an amine compound of the present embodiment includes the following steps. Step (a) : In the presence of a metal compound including a metal 5 belonging to Groups 8 to 10 and a phosphorus compound, the compound represented by the general formula (al) or (a2) is reacted with hydrogen and carbon monoxide. Step (b): The aldehyde compound obtained in the step (a) is reacted with ammonia, and reacted with hydrogen in the presence of 10 a catalyst. [0051] The preparation method of an amine compound of the present embodiment includes the preparation method of an aldehyde compound described above as the step (a). Therefore, the productivity and 15 yield of the aldehyde compound are excellent in the step (a), and thus, the productivity and yield of the amine compound which is a target compound are also excellent. Moreover, since the step (a) is the same as the step in the above-described "the preparation method of an aldehyde compound", 20 the description thereof will not be repeated. [0052] In the step (b) , by performing imination by reacting the aldehyde compound obtained in the step (a) and represented by the general formula (bl) or the following general formula (b2) with ammonia and 25 hydrogenation in the presence of a catalyst, an amine compound is synthesized. As the catalyst, metal catalysts such as nickel, platinum, 20 palladium, and ruthenium can be used. In a case where the aldehyde compound has a cyano group as a substituent, a ~CH2-NH2 group is produced by hydrogen reduction. [0053] 5 In this manner, in the step (b), the aldehyde group of the aldehyde compound becomes an amino group by imination, and the cyano group also becomes an amino group by hydrogen reduction, and thus, the amine compound represented by the following general formula (cl) having two amino groups is synthesized. Moreover, in a case where 10 X is a hydrogen atom, the amine compound represented by the following general formula (c2) is synthesized. [0054] 15 [0056] In the formula (cl) or (c2), n is the same as that in the general formula (al) or (a2). In a case where n is 1 or 2, the compound represented by the 21 general formula (cl) can be obtained as any one of "a compound in which the 2-position and the 5-position are substituted with predetermined groups {hereinafter, referred to as a 2, 5-isomer) " and "a compound in which the 2-position and the 6-position are substituted 5 with predetermined groups (hereinafter, referred to as a 2, 6-isomer) ", or can be obtained as a mixture including these in arbitrary proportions. In addition, each of the 2, 5-isomer and the 2,6-isomer can be obtained as any one of an endo-endo compound, an endo-exo compound, and an exo-exo compound depending on a steric configuration 10 of the substituent, or can be obtained as a mixture including at least two types of these in arbitrary proportions. [0057] Moreover, in a case where n is 0, the compound represented by the general formula (cl) can be obtained as any one of a cis-type 15 and a trans-type, or can also be obtained as a mixture including these in arbitrary proportions. In a case where n is 1 or 2, the compound represented by the general formula (c2) can be obtained as an endo compound or an exo compound, or can also be obtained as a mixture including these in 20 arbitrary proportions. In the present embodiment, the compound represented by the general formula (cl) is preferably obtained, and as the compound, the compound represented by the following chemical formula (3) in which n is 1 can be exemplified. 25 [0058] 22 [0059] Moreover, the amine compound represented by the chemical formula (3) can be obtained as any one of "a compound in which the 2-position 5 and the 5-position of bicyclo[2.2.1]heptane are substituted with aminomethyl groups (hereinafter, referred to as a 2, 5-isomer)" and "a compound in which the 2-position and the 6~position are substituted with aminomethyl groups (hereinafter, referred to as a 2, 6-isomer) ", or can be obtained as a mixture including these in arbitrary 10 proportions. In addition, each of the 2,5-isomer and the 2, 6-isomer can be obtained as any one of an endo^endo compound, an endo-exo compound, and an exo-exo compound depending on a steric configuration of the substituent, or can be obtained as a mixture including at least two types, of these in arbitrary proportions. 15 [0060] The above imination and hydrogenation reaction, specifically, can be performed in the following manner. First, an aldehyde compound, a solvent, and a catalyst are introduced into a reactor, and an ammonia gas is blown thereinto. Furthermore, hydrogen is injected at a 20 pressure until the pressure in the reactor becomes about 1 MPa, then, the temperature is raised to about 100 °C, and the reaction is allowed to proceed for about 1 hour to 10 hours at this temperature and pressure while supplying hydrogen. As the solvent, for example, an alcohol 23 having 1 to 8 carbon atoms or water is preferably used. Furthermore, after the reaction is finished, general catalyst filtration, desolventizing, and a purification step are performed, whereby a target amine compound can be obtained. 5 [0061] The preparation method of an isocyanate compound of the present embodiment includes the following steps. Step (a) : In the presence of a metal compound including a metal 10 belonging to Groups 8 to 10 and a phosphorus compound, the compound represented by the general formula (al) or (a2) is reacted with hydrogen and carbon monoxide. Step (b): The aldehyde compound obtained in the step (a) is reacted with ammonia, and reacted with hydrogen in the presence of 15 a catalyst. Step (c) : The amine compound obtained in the step (b) is reacted with a carbonylating agent. [0062] The preparation method of an isocyanate compound of the present 20 embodiment includes the preparation method of an aldehyde compound described above as the step (a) . Therefore, the productivity and yield of the aldehyde compound are excellent in the step (a), and thus, the productivity and yield of the isocyanate compound which is a target compound also are excellent. 25 [0063] Moreover, since the step (a) is the same as the step in the above-described "the preparation method of an aldehyde compound", 24 and the step (b) is the same as the step in the above-described "the preparation method of an amine compound", the description thereof will not be repeated. [0064] 5 In the step (c), by reacting the amine compound obtained in the step (b) represented by the general formula (cl) or (c2) with a carbonylating agent under predetermined conditions, an isocyanate compound represented by the following general formula (dl) or (d2) is synthesized. As the carbonylating agent, phosgene, urea 10 derivatives, carbonate derivatives, or carbon monoxide can be used. [0065] 1 In the formula (dl) or (d2) , n is the same as that in the general formula