Method for producing furan compound and furfural composition

Abstract

The present invention is aimed to provide an industrially advantageous method for producing a furan compound, in which a furan compound can be efficiently obtained in a high selectivity from a furfural compound. The present invention is concerned with a method for producing a furan compound including feeding, as a raw material, a furfural composition containing a furfural compound into a reactor and subjecting to a decarbonylation reaction in the presence of a catalyst to obtain a furan compound as a product, wherein a furfural dimer concentration in the furfural composition is 1,000 ppm by weight or less, and a peroxide value in the furfural composition is 0.01 mEq/kg or more and 1.0 mEq/kg or less.

Claims

1. A method for producing a furan compound comprising feeding, as a raw material, a furfural composition containing a furfural compound into a reactor and subjecting to a decarbonylation reaction in the presence of a catalyst to obtain a furan compound as a product, wherein a furfural dimer concentration in the furfural composition is 1,000 ppm by weight or less, and a peroxide value in the furfural composition is 0.01 mEq/kg or more and 0.90 mEq/kg or less, and wherein said catalyst is a solid catalyst comprising at least one metal selected from the group consisting of Ni, Ru, Ir, Pd, and Pt, wherein the furfural composition is prepared by distillation of a crude furural, said distillation comprising: (a) contacting the crude furfural with an anion exchange resin and/or a basic compound; (b) distilling the crude furfural from (a) to remove compounds having a higher boiling point than furfural; (c) distilling the crude furfural from (b), from which a compound having a higher boiling point than furfural has been removed, to remove compounds having a lower boiling point than furfural.

2. The method for producing a furan compound according to claim 1, wherein a concentration of a compound containing nitrogen in the furfural composition as a raw material is 0.1 ppm by weight or more and 50 ppm by weight or less expressed in terms of a nitrogen atom.

3. The method for producing a furan compound according to claim 1, wherein a concentration of the furfural compound in the furfural composition as a raw material is 99.00% by weight to 99.97% by weight.

4. The method for producing a furan compound according to claim 1, wherein a concentration of a 2-acetylfuran in the furfural composition as a raw material is 120 ppm by weight or more and 1,000 ppm by weight or less.

5. The method for producing a furan compound according to claim 1, wherein the catalyst is supported on a carrier wherein said carrier is a single metal oxide selected from the group consisting of Al.sub.2O.sub.3, SiO.sub.2, TiO.sub.2, ZrO.sub.2, and MgO, or a complex metal oxide thereof.

6. The method for producing a furan compound according to claim 1, wherein a column top pressure within a distillation column in (b) ranges from 0.12 to 28.2 kPa.

7. The method for producing a furan compound according to claim 1, wherein a column bottom temperature within a distillation column in (b) ranges from 60 to 125 C.

8. The method for producing a furan compound according to claim 1, wherein a proportion of the compound having a higher boiling point than furfural, which is removed in (b), is at least 30% by weight on the basis (100% by weight) of a total weight of compounds having a high boiling point, which are contained in the crude furfural.

9. The method for producing a furan compound according to claim 1, wherein a proportion of the compound having a higher boiling point than furfural, which is removed in (b), is at least 75% by weight on the basis (100% by weight) of a total weight of compounds having a high boiling point, which are contained in the crude furfural.

10. The method for producing a furan compound according to claim 1, wherein a reflux ratio in (b) ranges from 0.01 to 100.

11. The method for producing a furan compound according to claim 1, wherein a column top pressure within a distillation column in (c) ranges from 0.12 to 300 kPa.

12. The method for producing a furan compound according to claim 1, wherein a proportion of the compound having a higher boiling point than furfural, which is removed in (c), is at least 30% by weight on the basis (100% by weight) of a total weight of compounds having a high boiling point, which are contained in the crude furfural.

13. The method for producing a furan compound according to claim 1, wherein a proportion of the compound having a higher boiling point than furfural, which is removed in (c), is at least 75% by weight on the basis (100% by weight) of a total weight of compounds having a high boiling point, which are contained in the crude furfural.

14. The method for producing a furan compound according to claim 1, wherein a reflux ratio in (c) ranges from 0.01 to 200.

15. The method for producing a furan compound according to claim 1, wherein the compound having a higher boiling point than furfural is a compound having a boiling point higher by at least 5 C. than the boiling point of furfural at atmospheric pressure.

16. The method for producing a furan compound according to claim 15, wherein the compound having a higher boiling point than furfural is at least one compound selected from the group consisting of furfuryl alcohol, 2-acetylfuran, 2-furancarbonyl chloride, 5-methylfurfural, and furyl methyl ketone.

17. The method for producing a furan compound according to claim 1, wherein the compound having a lower boiling point than furfural is a compound having having a boiling point lower by at least 5 C. than the boiling point of furfural at atmospheric pressure.

18. The method for producing a furan compound according to claim 17, wherein the compound having a lower boiling point than furfural is at least one compound selected from the group consisting of 2,3-dihydrofuran, 2-methylfuran, formic acid, acetic acid, and 3-penten-2-one.

19. The method for producing a furan compound according to claim 1, wherein the number of theoretical plates in (b) and/or (c) ranges from 1 to 50 plates.

20. The method for producing a furan compound according to claim 1, wherein a feed temperature of the crude furfural into the distillation column ranges from 20 to 150 C.

Description

EXAMPLES

(1) Although the present invention is hereunder described in more detail with reference to Examples, it should be construed that the present invention is not limited by the following Examples so long as the gist of the present invention is not deviated. It is to be noted that in the following Examples, the analysis of moisture was performed by the Karl Fischer method (measurement apparatus: CA-21, manufactured by Mitsubishi Chemical Corporation). The analysis of each of furfural and a furfural dimer was performed by means of gas chromatography and calculated in terms of an area percentage. It is to be noted that a value resulting from subtraction of a moisture concentration from 100% by weight was calculated, and the remaining weight percent was calculated in terms of an area percentage of each component of the gas chromatography. It is to be noted that the furfural dimer concentration was the total of 5-(2-furanylcarbonyl)-2-furancarboxyaldehyde and bis-2-furylethanedione. The analysis of 2-acetylfuran was performed by means of gas chromatography and calculated in terms of an area percentage. The peroxide value was determined by the potassium addition redox titration in a nitrogen atmosphere (iodometry), and a potentiometric titrator (Titrando 808, manufactured by Metrohm Ltd.), a composite platinum electrode (manufactured by Metrohm, #6.0401.100, 3N KCl internal reference electrode electrolytic solution), and a titration agent (0.005N Na.sub.2SO.sub.3 aqueous solution) were used.

Production Example 1

(2) [Production of Furfural Composition]

(3) A glass-made chromatographic tube having a capacity of 100 cc and equipped with a jacket capable of being heated by circulating warm water was filled with 70 cc of an anion exchange resin (DIAION (a registered trademark), manufactured by Mitsubishi Chemical Corporation, model name: WA20), and furfural (purity: 98.7% by weight), manufactured by Kanematsu Chemicals Corporation was circulated at a rate of 140 cc/h into this glass-made chromatographic tube. On that occasion, a contact temperature between the anion exchange resin and the furfural was 40 C., and a pressure was atmospheric pressure.

(4) In the present Production Example, an operation of removing a high-boiling component from the furfural having been subjected to the treatment with the anion exchange resin is subsequently carried out. As a distillation column for performing the distillation of the foregoing liquid, an Oldershaw distillation column with 30 plates (number of theoretical plate: 20 plates) was used. The raw material furfural was continuously introduced at a flow rate of 90 cc/hr into a position of the 15th plate from the column bottom at a column top pressure of 6.7 kPa, a column bottom temperature of 98 C., and a reflux ratio of 1.0, and continuous distillation from the column top part was performed at a rate of 81 cc/hr, whereas continuous discharge from the column bottom was performed at a rate of 9 cc/hr. According to the present continuous distillation, a furfural liquid (column top distillate) having a composition such that the furfural purity was 99.95%, and a sum total of light-boiling components was 0.03% was obtained from the column top. It is to be noted that an oil bath was used as a heat source of the distillation, and a temperature of the oil bath was set to 131 C.

(5) In order to perform an operation for removing the light-boiling component in the obtained column top distillate, an Oldershaw distillation column with 25 plates (number of theoretical plate: 15 plates) was used. The column top distillate was continuously introduced at a flow rate of 100 cc/hr into a position of the 10th plate from the column bottom at a column top pressure of 33.3 kPa, a column bottom temperature of 130 C., and a reflux ratio of 50; continuous distillation from the column top part was performed at a rate of 1 cc/hr; continuous discharge from the column bottom was performed at a rate of 2 cc/hr; and sidestream discharge from a position of the 13th plate from the column bottom was performed at a rate of 97 cc/hr. According to the present continuous distillation, the obtained sidestream discharge liquid was obtained in such a composition that the furfural purity was 99.97%, the furfural dimer content was not more than a detection limit, the peroxide value was 0.32 mEq/kg, and the nitrogen compound concentration was 2.0 ppm by weight in terms of a nitrogen atom. The acetylfuran concentration was 293 ppm by weight. It is to be noted that an oil bath was used as a heat source of the distillation, and a temperature of the oil bath was set to 175 C.

Production Example 2

(6) [Production of Furfural Composition]

(7) The same procedures as in Production Example 1 were all carried out, except for performing the distillation for separating the light-boiling component by means of continuous distillation from the column top part at a rate of 1 cc/hr and performing the continuous discharge from the column bottom at a rate of 99 cc/hr. It is to be noted that an oil bath was used as a heat source of the distillation, and a temperature of the oil bath was set to 145 C. According to the present continuous distillation, the obtained bottom discharge liquid was obtained in such a composition that the furfural purity was 99.78%, the furfural dimer content was 0.03% by weight, the peroxide value was 1.03 mEq/kg, and the nitrogen compound concentration was 1.3 ppm by weight in terms of a nitrogen atom.

Production Example 3

(8) [Production of Furfural Composition]

(9) With respect to the furfural composition obtained in Production Example 2, an Oldershaw distillation column with 10 plates (number of theoretical plate: 5 plates) was used. The raw material furfural was continuously introduced at a flow rate of 90 cc/hr into a position of the 5th plate from the column bottom at a column top pressure of 6.7 kPa, a column bottom temperature of 98 C., and a reflux ratio of 1.0, and continuous distillation from the column top part was performed at a rate of 89 cc/hr, whereas continuous discharge from the column bottom was performed at a rate of 1 cc/hr. According to the present continuous distillation, the furfural liquid from the column top (column top distillate) was obtained from the column top in such a composition that the furfural purity was 99.94%, the furfural dimer content was not more than a detection limit, the peroxide value was 0.57 mEq/kg, and the nitrogen compound concentration was 1.3 ppm by weight in terms of a nitrogen atom.

Production Example 4

(10) [Production of Furfural Composition]

(11) In Production Example 1, the distillation was carried out in such a mariner that the air leakage of the distillation column was less than 1.3 kPa/hr. According to the present continuous distillation, the furfural liquid from the column top (column top distillate) was obtained from the column top in such a composition that the furfural purity was 99.97%, the furfural dimer content was 0.05 ppm by weight, the peroxide value was 0.19 mEq/kg, and the nitrogen compound concentration was 2.0 ppm by weight in terms of a nitrogen atom.

Production Example 5

(12) [Production of Furfural Composition]

(13) A 500-L SUS304-made pot was filled with 35 kg of an anion exchange resin (DIAION (a registered trademark), manufactured by Mitsubishi Chemical Corporation, model name: WA20), and 100 kg of furfural (purity: 98.7% by weight), manufactured by Kanematsu Chemicals Corporation was filled in this pot. Thereafter, the contents were stirred at 40 C. for 30 minutes, and the liquid and the resin were separated from each other by a filter. The pressure was atmospheric pressure. Thereafter, the liquid was again filled in the pot, 35 kg of the anion exchange resin after washing was filled, and the contents were stirred at 40 C. for 30 minutes. These operations were repeated until the moisture of the liquid reached 200 ppm by weight or less.

(14) In the present Production Example, an operation of removing a high-boiling component from the furfural having been subjected to the treatment with the anion exchange resin is subsequently carried out. As a distillation column for performing the distillation of the foregoing liquid, a distillation column having the number of theoretical plate of 20 plates was used. The raw material furfural was continuously introduced at a flow rate of 30 L/hr into a position of the 15th plate from the column bottom at a column top pressure of 6.7 kPa, a column bottom temperature of 98 C., and a reflux ratio of 1.0, and continuous distillation from the column top part was performed at a rate of 27 L/hr, whereas continuous discharge from the column bottom was performed at a rate of 3 L/hr. According to the present continuous distillation, a furfural liquid (column top distillate) having a composition such that the furfural purity was 99.95%, and a sum total of light-boiling components was 0.03% was obtained from the column top. It is to be noted that steam was used as a heat source of the distillation, and a steam temperature was set to 130 C.

(15) In order to perform an operation for removing the light-boiling component in the obtained column top distillate, a packed column having the number of theoretical plate of 23 plates was used. The column top distillate was continuously introduced at a flow rate of 50 L/hr into a position of the 5th plate from the column bottom at a column top pressure of 33.3 kPa, a column bottom temperature of 120 C., and a reflux ratio of 100; continuous distillation from the column top part was performed at a rate of 0.5 L/hr; continuous discharge from the column bottom was performed at a rate of 1 L/hr; and sidestream discharge from a position of the 13th plate from the column bottom was performed at a rate of 48.5 L/hr. According to the present continuous distillation, the obtained sidestream discharge liquid was obtained in such a composition that the furfural purity was 99.97%; the furfural dimer content was not more than a detection limit; the peroxide value was 0.12 mEq/kg; the acetylfuran concentration was 200 ppm by weight; and the nitrogen compound concentration was 2.0 ppm by weight in terms of a nitrogen atom.

Example 1

(16) [Production of Furan Compound by Decarbonylation Reaction of Furfural Composition]

(17) In an SUS-made reaction tube having an inside diameter of 13.4 mm, 12.0 g of a supported Pd catalyst (1% by weight Pd1% by weight K/ZrO.sub.2) which had been crushed to a size of 0.6 mm or less was filled, and the temperature of the catalyst was increased to 231 C. under circulation of 22.5 mmol/h of hydrogen and 292.5 mmol/h of nitrogen. The furfural composition purified in Production Example 1 was allowed to pass through a vaporizer heated at 245 C. and vaporized, followed by feeding at a flow rate of 362.2 mmol/h, to commence a decarbonylation reaction. At that time, a hydrogen/furfural ratio was 0.05. A reaction pressure was 0.4 MPa in terms of an absolute pressure.

(18) A part of the reaction gas obtained from an outlet of the reaction tube was introduced into a gas chromatograph (GC), thereby quantitating the furan compound, carbon monoxide, nitrogen, and other products.

(19) For the gas chromatographic analysis of inorganic gases, such as carbon monoxide, nitrogen, etc., a thermal conductivity detector was used as a detector, and a packed column filled with Molecular Sieve 13X (a trade name, manufactured by GL Sciences Inc., mesh 60/80) and having a column length of 3 in was used as a column. It is to be noted that the analysis was carried out by setting a temperature of each of the sample introducing part and the detection part to 90 C., a temperature of the column to 70 C., and a current value to be flown into the detection part to 70 mA, respectively.

(20) For the gas chromatographic analysis of organic gases, such as furfural, furan, etc., a thermal conductivity detector was used as a detector, and a packed column filled with Thermon-1000 (a trade name, manufactured by GL Sciences Inc., medium polarity) and having a column length of 3 m was used as a column. It is to be noted that the analysis was carried out in such a manner that a temperature of the sample introducing part was set to 200 C.; a temperature of the detection part was set to 220 C.; a column temperature was increased at a rate of 3 C./min from 80 C. to 110 C.; after reaching 110 C., the temperature was increased to 225 C. at a rate of 5 C./min; after reaching 225 C., the temperature was kept for 17 minutes; and a current value to be flown into the detection part was set to 80 mA.

(21) It is to be noted that a conversion of the furfural compound (furfural conversion) (%) and a selectivity of the furan compound (furan selectivity) (%) were calculated according to the following equations. Furfural conversion (%)=[1{(Residual amount of furfural compound after reaction (mol))/(Feed amount of furfural compound (mol))}]100 Furan selectivity (%)=[{(Yield of furan compound (%))/(Conversion of furfural compound (%))}100=[{(Formation amount of furan compound (mol))/(Feed amount of furfural compound (mol))}100/(Furfural conversion (%))]100

(22) As a result of performing the decarbonylation reaction under the above-described condition, 60 hours after commencing the reaction, the furfural conversion was 99.64%, and the furan selectivity was 99.64%. The results are shown in Table 1.

Example 2

(23) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 1, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to the furfural composition of Production Example 3. 60 hours after commencing the reaction, the furfural conversion was 99.35%, and the furan selectivity was 99.51%. The results are shown in Table 1.

Example 3

(24) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 1, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to the furfural composition of Production Example 4. The furfural conversion was 99.38%, and the furan selectivity was 98.61%, at 60 hours after commencing the reaction. The results are shown in Table 1.

Comparative Example 1

(25) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 1, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to the furfural composition of Production Example 2. The furfural conversion was 97.35%, and the furan selectivity was 97.73%, at 60 hours after commencing the reaction. The results are shown in Table 1.

Example 4

(26) After mixing 5.0 g of the furfural composition of Production Example 5 and 1.0 g of a supported Pd catalyst (1% by weight Pd1% by weight K/ZrO.sub.2) which had been crushed to a size of 0.6 mm or less, those are filled in a 200-mL autoclave. After purging the autoclave with nitrogen three times, the autoclave was evacuated, and 58 cc of hydrogen was then injected. Nitrogen was charged in the autoclave to set the pressure to 0.4 MPa, and a liquid phase decarbonylation reaction was carried out at an internal temperature of the autoclave of 200 C. for 5 hours. The reaction mixture was cooled and then taken out, followed by gas chromatographic analysis. As a result, the furfural conversion was 79.96%, and the furan selectivity was 99.86%. The results are shown in Table 1.

Example 5

(27) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 4, except for changing the furfural composition as a raw material from the furfural composition of Production Example 5 to the furfural composition of Production Example 1. The furfural conversion was 77.55%, and the furan selectivity was 99.85%, at 5 hours after commencing the reaction. The results are shown in Table 1.

Example 6

(28) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 5, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to the furfural composition of Production Example 4. The furfural conversion was 74.61%, and the furan selectivity was 99.75%, at 5 hours after commencing the reaction. The results are shown in Table 1.

Comparative Example 2

(29) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 5, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to the furfural composition of Production Example 2. The furfural conversion was 70.71%, and the furan selectivity was 99.59%, at 5 hours after commencing the reaction. The results are shown in Table 1.

Comparative Example 3

(30) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 5, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to a furfural composition resulting from mixing the furfural composition of Production Example 1 with the bottom liquid obtained by light-boiling separation distillation of Production Example 1 in a weight ratio of 97/2. At 5 hours after commencing the reaction, the furfural conversion was 67.47%, and the furan selectivity was 99.64%. The results are shown in Table 1.

Comparative Example 4

(31) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 5, except for changing the furfural composition as a raw material from the furfural composition of Production Example 1 to a furfural composition resulting from mixing the furfural composition of Production Example 2 with bis-2-furylethanedione (manufactured by Aldrich, purity: 98%) such that the furfural dimer concentration was 0.11% by weight. At 5 hours after commencing the reaction, the furfural conversion was 66.72%, and the furan selectivity was 99.75%. The results are shown in Table 1.

(32) TABLE-US-00001 TABLE 1 Furfural composition Concentration of the compound Decarbonylation reaction containing Furfural dimer Peroxide Gas phase/ Furfural Furan nitrogen concentration value Liquid conversion selectivity [ppm by mass] [ppm by mass] [mEq/kg] phase [%] [%] Example 1 7 ND 0.32 Gas phase 99.64 99.64 Example 2 1.3 ND 0.57 Gas phase 99.35 99.51 Example 3 7 500 0.19 Gas phase 99.38 98.61 Comparative 1.3 300 1.03 Gas phase 97.35 97.73 Example 1 Example 4 2 ND 0.12 Liquid phase 79.96 99.86 Example 5 2 ND 0.32 Liquid phase 77.55 99.85 Example 6 2 500 0.19 Liquid phase 74.61 99.75 Comparative 1.3 300 1.03 Liquid phase 70.71 99.59 Example 2 Comparative 3 200 1.35 Liquid phase 67.47 99.64 Example 3 Comparative 1.3 1100 1.03 Liquid phase 66.72 99.75 Example 4 ND: Not more than a detection limit

(33) The following may be said from Table 1. Namely, in comparison of the results regarding the conversion of the furfural compound and the selectivity of the furan compound in the decarbonylation reaction of Examples 1 to 6 and Comparative Examples 1 to 4, it is noted that in all of the gas phase reaction and the liquid phase reaction, when a furfural composition in which each of the furfural dimer concentration and the peroxide value falls within a specified range is used as the raw material for production of a furan compound, the furfural composition becomes useful as the raw material for industrial production of a furan compound since the composition is high in both the conversion and the selectivity.

Production Example 6

(34) [Production of Furfural Composition]

(35) A glass-made chromatographic tube having a capacity of 100 cc and equipped with a jacket capable of being heated by circulating warm water was filled with 70 cc of an anion exchange resin (DIAION (a registered trademark), manufactured by Mitsubishi Chemical Corporation, model name: WA20), and furfural (purity: 98.7% by weight), manufactured by Kanematsu Chemicals Corporation was circulated at a rate of 140 cc/h into this glass-made chromatographic tube. On that occasion, a contact temperature between the anion exchange resin and the furfural was 40 C., and a pressure was atmospheric pressure.

(36) Using an Oldershaw distillation column having a column diameter of 35 mm and the number of theoretical plate of 5 plates, 1,000.0 g of the obtained furfural was distilled at a column top pressure of 13.3 kPa and a column bottom temperature of 102 C.

(37) An oil bath was used as a heat source of the distillation, and a temperature of the oil bath was set to 120 C. A distillate was discharged successively from an initial distillate containing a lot of a light-boiling component, thereby acquiring furfural compositions Fr-1 to Fr-6, respectively. It is to be noted that Fr-1 to Fr-6 are distillates discharged 1 hour, 2 hours, 3 hours, 4.2 hours, 5.5 hours, and 7.2 hours, respectively after commencing the distillation.

(38) Then, when the distillation reached a proportion of 90% by weight relative to the furfural in the column bottom liquid of the distillation column, the distillation was terminated. Concentrations of the furfural of each of Fr-1 to Fr-6 and the 2-acetylfuran are shown in the following Table 2.

(39) TABLE-US-00002 TABLE 2 Production Example 6 Fr-1 Fr-2 Fr-3 Fr-4 Fr-5 Fr-6 Raw material Furfural purity 99.26 99.85 99.53 99.77 99.68 95.64 furfural [% by weight] composition 2-Acetylfuran content 359 532 922 1343 2255 4624 [ppm by weight]

Production Example 7

(40) [Production of Furfural Composition]

(41) Furfural compositions Fr-1 to Fr-6 were produced under exactly the same conditions as in Production Example 6, except for using an Oldershaw distillation column having the number of theoretical plate of 20 plates. Fr-1 to Fr-6 are distillates discharged 1 hour, 2 hours, 3 hours, 4.2 hours, 5.5 hours, and 7.2 hours, respectively after commencing the distillation.

(42) Concentrations of the furfural of each of Fr-1 to Fr-6 and the 2-acetylfuran are shown in the following Table 3.

(43) TABLE-US-00003 TABLE 3 Production Example 7 Fr-1 Fr-2 Fr-3 Fr-4 Fr-5 Fr-6 Raw material Furfural purity 98.35 99.96 99.92 99.72 99.55 99.21 furfural [% by weight] composition 2-Acetylfuran content 40 110 293 341 789 1357 [ppm by weight]

Example 7

(44) [Production of Furan Compound by Decarbonylation Reaction of Furfural Composition]

(45) In a glass-type reaction tube having an inside diameter of 6 mm, 0.75 g of a supported Pd catalyst (1% by weight Pd1% by weight K/ZrO.sub.2) which had been crushed to a size of 0.6 mm or less was filled, and the temperature of the catalyst was increased to 231 C. under circulation of 2.25 mmol/h of hydrogen and 85.71 mmol/h of nitrogen. The furfural composition (Fr-2) purified in Production Example 6 was allowed to pass through a vaporizer heated at 182 C. and vaporized, followed by feeding at a flow rate of 36.22 mmol/h, to commence a decarbonylation reaction. At that time, a hydrogen/furfural compound ratio was 0.062. A reaction pressure was 0.1 MPa in terms of an absolute pressure.

(46) A part of the reaction gas obtained from an outlet of the reaction tube was introduced into a gas chromatograph, thereby quantitating the furan compound, carbon monoxide, nitrogen, and other products.

(47) As a result of performing the decarbonylation reaction under the above-described condition, 12 hours after commencing the reaction, the furfural conversion was 99.5%, and the furan selectivity was 93.5%. The results are shown in Table 4.

Example 8

(48) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 7, except for changing the furfural composition as a raw material from Fr-2 of Production Example 6 to Fr-3 of Production Example 6. At 12 hours after commencing the reaction, the furfural conversion was 97.7%, and the furan selectivity was 94.1%. The results are shown in Table 4.

Example 9

(49) The decarbonylation reaction was carried out under exactly the same conditions as in Example 7, except for changing the furfural composition as a raw material from Fr-2 of Production Example 6 to Fr-3 of Production Example 7. At 12 hours after commencing the reaction, the furfural conversion was 99.5%, and the furan selectivity was 99.5%. The results are shown in Table 4.

Comparative Example 5

(50) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 7, except for changing the furfural composition as a raw material from Fr-2 of Production Example 6 to Fr-6 of Production Example 6. At 12 hours after commencing the reaction, the furfural conversion was 90.9%, and the furan selectivity was 93.5%. The results are shown in Table 4.

Comparative Example 6

(51) The decarbonylation reaction was carried out under exactly the same conditions as in Example 9, except for changing the furfural composition as a raw material from Fr-3 of Production Example 7 to Fr-2 of Production Example 7. At 12 hours after commencing the reaction, the furfural conversion was 88.3%, and the furan selectivity was 99.3%. The results are shown in Table 4.

Comparative Example 7

(52) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 7, except for changing the furfural composition as a raw material from Fr-2 of Production Example 6 to Fr-4 of Production Example 6. At 12 hours after commencing the reaction, the furfural conversion was 98.6%, and the furan selectivity was 92.8%. The results are shown in Table 4.

Comparative Example 8

(53) The production of a furan compound through the decarbonylation reaction was carried out under exactly the same conditions as in Example 7, except for changing the furfural composition as a raw material from Fr-2 of Production Example 6 to purchased furfural (manufactured by Kanematsu Chemicals Corporation). At 12 hours after commencing the reaction, the furfural conversion was 85.6%, and the furan selectivity was 92.5%. The results are shown in Table 4.

(54) TABLE-US-00004 TABLE 4 Comparative Comparative Comparative Comparative Example 7 Example 8 Example 9 Example 5 Example 6 Example 7 Example 8 Raw material Furfural purity (% by weight) 99.85 99.53 99.92 95.64 99.96 99.77 99.77 furfural 2-Acetylfuran content 532 922 293 4624 110 1343 1245 composition (ppm by weight) Moisture concentration 280 255 385 310 224 270 1235 (ppm by weight) Furfural dimer concentration ND ND ND ND ND ND ND (ppm by weight) Peroxide value (mEq/kg) 0.78 0.65 0.35 1.35 0.59 0.57 1.24 Reaction Furfural conversion (%) 99.5 97.7 99.5 90.9 88.3 98.6 85.6 results Furan selectivity (%) 93.5 94.1 99.5 93.5 99.3 92.8 92.5 Furan yield (%) 93.0 91.9 99.0 85.0 87.7 91.5 79.2

(55) From the decarbonylation reaction results of Examples 7 to 9 and Comparative Examples 5, 7, and 9, it is noted that the lower the 2-acetylfuran concentration, the higher the furan yield is.

(56) Meanwhile, from the results of Examples 7 to 9 and Comparative Example 6, it is noted that when the 2-acetylfuran concentration is too low, the furan yield is lowered.

(57) While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. It is to be noted that the present application is based on a Japanese patent application filed on Mar. 27, 2015 (Japanese Patent Application No. 2015-067199), and the contents are incorporated herein by reference.