Solid catalyst for dehydration of sugar alcohol and method for preparing dianhydrosugar alcohol using said catalyst

Abstract

The present invention addresses the problem of providing a solid catalyst capable of achieving high selectivity and high yield for isosorbide, preferably at the same time, in a dehydration reaction by which dianhydrosugar alcohol is obtained from a sugar alcohol, particularly, in a dehydration reaction by which isosorbide is obtained from sorbitol. The above-mentioned problem is solved by a solid catalyst for a dehydration reaction for preparing dianhydrosugar alcohol from sugar alcohol, said catalyst including an H-type zeolite having an atomic composition ratio of Si to Al (Si/Al) of more than 20.

Claims

1. A solid, catalyst for a dehydration catalyst, comprising an H-type zeolite having an atomic composition ratio of Si to Al (Si/Al) of more than 20.

2. The solid, dehydration catalyst according to claim 1, wherein the Si/Al ratio is 400 or less.

3. A method for producing a dianhydrosugar alcohol from a sugar alcohol, comprising bringing the sugar alcohol into contact with the catalyst according to claim 1.

4. The method according to claim 3, wherein the amount of the H-type zeolite contained in the catalyst is 5 to 60 parts by mass, based on 100 parts by mass of the sugar alcohol.

5. The method according to claim 3, further comprising maintaining the sugar alcohol brought into contact with the catalyst under ambient pressure or under reduced pressure.

6. The method according to claim 3, further comprising maintaining the sugar alcohol brought into contact with the catalyst at a temperature of 110 C. to 170 C.

7. The method according to claim 3, further comprising maintaining the sugar alcohol brought into contact with the catalyst for 1.5 hours or more.

8. The method according to claim 3, wherein the sugar alcohol is selected from the group consisting of sorbitol, mannitol and iditol.

9. The method according to claim 3, wherein the sugar alcohol is sorbitol, and the dianhydrosugar alcohol is isosorbide.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the chemical reaction formula of a reaction for obtaining isosorbide from sorbitol.

(2) FIG. 2 shows a graph obtained by plotting an isosorbide yield .sub.1 and a total yield of by-products .sub.2 with respect to a Si/Al ratio regarding zeolites disclosed in Examples and Comparative Examples in Patent Literature 1 based on data in Table 1.

(3) FIG. 3 is a graph showing the relationship between an isosorbide yield and the type of a zeolite and a Si/Al ratio.

DESCRIPTION OF EMBODIMENTS

(4) The present invention relates to a solid catalyst for a dehydration reaction for producing a dianhydrosugar alcohol from a sugar alcohol, comprising an H-type zeolite in which the atomic composition ratio of Si to Al, Si/Al, is more than 20, and a method for producing a dianhydrosugar alcohol from a sugar alcohol (for example, producing isosorbide from sorbitol) using the same.

(5) As for the sugar alcohol in the present invention, compounds obtained by reducing saccharides, the so-called carbohydrates, to alcohols are used. Said saccharides include saccharides such as aldose and ketose. Examples of sugar alcohols reduced from them and suitable for the present invention include mannitol, iditol and sorbitol. Among them, sorbitol is particularly preferred because the isosorbide that is a produced by its dehydration has a wide variety of uses as a raw material in medicines and plastics.

(6) In the present invention, a dianhydrosugar alcohol refers to a sugar alcohol obtained by removing two molecules of water from a sugar alcohol. For example, when sorbitol is used as a sugar alcohol, various side reactions occur and various intermediates and products can be produced from the sorbitol as described above. In the case of the present invention, preferably, among them, isosorbide is obtained as a dianhydrosugar alcohol. In other words, the above dianhydrosugar alcohol is particularly preferably an isosorbide. Therefore, the present invention will be described below mainly with sorbitol as the sugar alcohol and isosorbide as the dianhydrosugar alcohol, but the description is also similarly applied to other sugar alcohols and the like. For example, when mannitol is used as the above sugar alcohol, preferably, fructose is obtained as the dianhydrosugar alcohol.

(7) In order to achieve the objects of the present invention, it is preferred that the solid catalyst used in the above dehydration reaction in the present invention has a catalyst effect in each of the condensation reactions in two stages in FIG. 1 and can be efficiently separated and removed from the reaction system and moreover does not damage equipment or the environment. From such a viewpoint, in the present invention, zeolites are adopted, and among them, particularly H-type zeolites are preferred.

(8) Therefore, the solid catalyst for a dehydration reaction in the present invention is a catalyst containing a zeolite, preferably a catalyst containing an H-type zeolite.

(9) The catalyst can comprise, for example, a binder and silica, in addition to the zeolite, in a range that does not impair the effects of the present invention.

(10) In addition, the catalyst can also comprise the zeolite as the only component, in other words, the above catalyst can also consist of only the zeolite. In this case, the present invention relates to a solid catalyst for a dehydration reaction for producing a dianhydrosugar alcohol from a sugar alcohol, which is a zeolite, preferably an H-type zeolite.

(11) Here, a zeolite is a generic term for crystalline porous aluminosilicates, and in the present invention, among zeolites, zeolites (also described as beta-type zeolites), preferably H-type zeolites, are used as described above.

(12) A zeolite is a synthetic zeolite in which the unit cell composition is represented by the following average composition formula:
M.sub.m/x[Al.sub.mSi.sub.(64-m)O.sub.128].Math.pH.sub.2O
wherein M is a cationic species (for example, Na.sup.+), x is a valence of the above M, m is a number of larger than 0 and less than 64, and p is a number of 0 or more.

(13) In addition, an acid type zeolite is also referred to as an H-type zeolite or a proton-type zeolite and has a structure obtained by ion-exchanging the cationic sites of the zeolite and replacing them by H.sup.+. When the H-type zeolite is used in the present invention, a slight amount of M that is not replaced may be contained in the H-type zeolite in a range that does not impair the effects of the present invention. H-type zeolites are widely used for catalysts for various reactions, adsorbents for chemical substances or the like, because their H.sup.+ acts as a Bronsted acid.

(14) Therefore, a method for producing the aforementioned H-type zeolite is already known, and various products are commercially available. For example, as H-type zeolites that can be used in the present invention, H-BEA-25 (Si/Al=12.5) manufactured by Clariant Catalysts (Japan) K.K., H-BEA-35 (Si/Al=17.5) manufactured by Clariant Catalysts (Japan) K.K., H-BEA-50 (Si/Al=25) manufactured by Clariant Catalysts (Japan) K.K., H-BEA-150 (Si/Al=75) manufactured by Clariant Catalysts (Japan) K.K., and the like are commercially available.

(15) In the H-type zeolite in the present invention, the atomic composition ratio of Si to Al, Si/Al ratio, needs to be more than 20 and can also be, for example, 22 or more or 24 or more. When the Si/Al ratio is 20 or less, the yield of isosorbide decreases. It is considered that an H-type zeolite having a Si/Al ratio of 20 or less generally has a high acidity, and therefore it is expected that the yield is high when the Si/Al ratio is 20 or less, whereas such is not the case, and the yield increases in the case of higher Si/Al ratios. The reasons are not clear. It is presumed that when the Si/Al ratio is 20 or less, the acid content is large, but the acid strength is insufficient. Or the fact that the acid content is too large, and therefore the amount of carbon deposited on the catalyst surface increases, and the reaction is inhibited is also presumed as another factor. Furthermore, the fact that at a Si/Al ratio of 20 or less, factors in terms of shapes such as pore diameter and pore volume decrease isosorbide selectivity is also presumed as one of the reasons.

(16) The atomic composition ratio of Si to Al (Si/Al ratio) can be measured by chemical analysis or elemental analysis by an atomic absorption method.

(17) When the atomic composition ratio of Si to Al (Si/Al ratio) is too large, the acidity of the H-type zeolite decreases, and the reaction yield decreases; this is not practical. Therefore, in the H-type zeolite in the present invention, the Si/Al ratio is preferably 400 or less and can be, for example, 300 or less, 200 or less, 100 or less, or 80 or less.

(18) Therefore, the Si/Al ratio of the H-type zeolite is preferably, for example, in the range of 20<Si/Al ratio400, 20<Si/Al ratio200, 22Si/Al ratio100, or 24Si/Al ratio80.

(19) In addition, the H-type zeolite in the present invention can have, for example, a specific surface area of 50 m.sup.2/g to 1000 m.sup.2/g. When the specific surface area is too small, the adsorption performance of the H-type zeolite is not sufficient. Conversely, when the specific surface area is too large, the following problem is likely to occur: the desorption of the product is prevented and the yield is likely to decrease. From such a viewpoint, the H-type zeolite in the present invention preferably has a specific surface area of 100 m.sup.2/g to 800 m.sup.2/g, particularly preferably 400 m.sup.2/g to 600 m.sup.2/g.

(20) The method for producing a dianhydrosugar alcohol (for example, isosorbide) from a sugar alcohol (for example, sorbitol) using the solid catalyst of the present invention comprises bringing a sugar alcohol (for example, sorbitol) into contact with the catalyst. In this case, for example, the reaction may be carried out by mixing sorbitol in the form of a solid as it is with the catalyst, or the reaction can also be carried out by mixing sorbitol with the catalyst after the former is turned into the form of a liquid, preferably the form of an aqueous solution.

(21) The mixing can be performed, for example, by stirring, and the stirring can be performed using a stirring bar, a stirring blade or similar. In bringing a sugar alcohol (for example, sorbitol) into contact with the catalyst, for example, when the amounts of these are small, they are stirred and mixed using a stirring bar. When the amounts of these increase, stirring can be performed by a motor-driven ribbon type stirring blade or similar.

(22) In one preferred embodiment of the present invention, when a sugar alcohol is brought into contact with the catalyst, mixing is performed using a stirring bar or a stirring blade because uniform and sufficient mixing can be achieved.

(23) In such a dehydration reaction of sorbitol, when the amount of the H-type zeolite contained in the catalyst (hereinafter also simply referred to as the amount of the catalyst for convenience) is too small, a sufficient reaction rate is not obtained, and the conversion of sorbitol decreases. On the other hand, when the amount of the catalyst is too large, not only is the catalyst wasted, but side reactions are promoted, and the yield of isosorbide conversely decreases. From such a viewpoint, in the present invention, the amount of the catalyst is preferably 5 to 60 parts by mass, based on 100 parts by mass of sorbitol. The amount of the catalyst is more preferably 10 to 60 parts by mass, more preferably 20 to 60 parts by mass or 25 to 60 parts by mass, based on 100 parts by mass of sorbitol.

(24) The dehydration reaction of the present invention is accompanied by many side reactions, and therefore the control of the reaction temperature is important. When the reaction temperature is too low, the reaction rate is small and a long reaction time is necessary and therefore the practicality is insufficient. When the temperature is too high, the desired isosorbide selectivity decreases, and the amount of by-products increases. From such a viewpoint, a preferred reaction temperature in the present invention is about 110 C. to about 170 C., more preferably 115 C. to 160 C., and particularly preferably 120 C. to 150 C., or 120 C. to 145 C., or 125 C. to 135 C.

(25) In addition, the dehydration reaction in the present invention can be performed by maintaining the sugar alcohol brought into contact with the catalyst under any pressure. The dehydration reaction is preferably performed under ambient pressure or under reduced pressure, and more preferably performed under reduced pressure, for example, under a pressure of 1000 hPa or less, 850 hPa or less, 750 hPa or less, 500 hPa or less, 400 hPa or less, or 10 hPa or less. On the other hand, the lower limit of the pressure only depends on the reaction apparatus used and is not particularly limited, and it is generally sufficient that the reaction is carried out under a pressure of 5 hPa to ambient pressure.

(26) The reaction time of the dehydration reaction in the present invention is preferably 1 hour or more, more preferably 1.5 hours or more, because when the reaction time is too short, a sufficient isosorbide yield cannot be achieved. However, when the reaction time is too long, cost increase as well as an increase in the generation of by-products are concerns. From such a viewpoint, the reaction time is preferably 1 hour to 10 hours, more preferably 1.5 hours to 8 hours, and particularly preferably 2 hours to 6 hours.

(27) For example, in the method of the present invention, it is possible to mix the H-type zeolite that is a solid acid catalyst, as it is, with a sugar alcohol in the solid state of the raw material, and carry out the reaction at a predetermined temperature for a predetermined time as described above, and it is possible to carry out the reaction in a so-called batchwise method. Or it is also possible to fill a reaction tube with a shaped H-type zeolite catalyst, introduce therein a sugar alcohol turned into the form of a liquid, and continuously react it in a flow.

(28) By extraction with water of the mixture of the products and the remaining raw material (sorbitol) and the catalyst after the reaction, followed by filtration, the catalyst and the products can be separated. The catalyst separated by the filtration can be reused after being dried and calcined.

(29) As described above, in the dehydration reaction of sorbitol, many types of intermediates can be produced, and only particular ones among them can produce isosorbide. With the catalyst of the present invention and the method of the present invention using said catalyst, the intended production of isosorbide with a high selectivity and a high yield is achieved.

(30) The present invention will be described below in Examples, but the present invention is not limited in any way by these Examples and the like.

EXAMPLES

Example 1

(31) 182 mg of a sorbitol powder (manufactured by KANTO CHEMICAL CO., INC.) was put in a reaction container (flask) and mixed well with 50 mg of an H-type beta zeolite (H-BEA-50 manufactured by Clariant Catalysts (Japan) K.K., Si/Al=25). The flask containing the mixture of the sorbitol and H-BEA-50 was heated in an oil bath to 130 C. and further maintained at 130 C. for 2 hours (ambient pressure). 20 ml of water was added to the mixture followed by filtration to separate H-BEA-50. The aqueous solution was analyzed by high performance liquid chromatography, and the products were quantified. The yield of isosorbide was 65%.

Example 2

(32) A reaction was performed using the same method and conditions as Example 1 except that H-BEA-150 (manufactured by Clariant Catalysts (Japan) K.K., H-type zeolite, Si/Al=75) was used instead of H-BEA-50. The reaction was carried out six times in total with the reaction time changed to 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, and 4 hours. The yield of isosorbide was 17% for 0.5 hours; 40% for 1 hour and 62% for 1.5 hours; and 68% for all of 2 hours, 3 hours, and 4 hours.

Example 3

(33) A reaction was carried out as in Example 2 except that the reaction temperature was 140 C. The yield of isosorbide was 42% for a reaction time of 0.5 hours, 67% in the case of 1 hour, 68% for 1.5 hours, 65% for 2 hours, 62% for 3 hours, and 59% for 4 hours.

Example 4

(34) A reaction was performed using the same method and conditions as Example 1 except that the reaction temperature was 120 C. The reaction was carried out seven times in total with the reaction time changed to 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 7 hours, and 8 hours. The yield of isosorbide was 14% for a reaction time of 1 hour, 32% when the reaction time was 2 hours, 58% for 3 hours, 68% for 4 hours, 74% for 5 hours, 70% for 7 hours, and 70% for 8 hours.

Example 5

(35) A reaction was performed for 5 hours using the same method as Example 2 using the same unused catalyst (H-BEA-150) as Example 2. The yield of isosorbide at this time was 74%. The catalyst after use was recovered by filtration, dried at 120 C. for 5 hours, and then calcined in air at 500 C. for 3 hours to regenerate the catalyst. Repeating the reaction and regeneration 4 times, the results showed that the first repetition gave 74% of isosorbide yield equivalent to that of the unused catalyst, the yield of isosorbide in the second repetition was 71%, 66% in the third repetition and 62% in the fourth repetition was.

Example 6

(36) A reaction was performed at 140 C. for 2.5 hours using the same method as Example 2 except that 0.26 g (sorbitol content 0.182 g) of a commercial sorbitol aqueous solution (manufactured by KANTO CHEMICAL CO., INC., concentration 70% by mass) was mixed with 0.05 g of an H-BEA-150 catalyst. The yield of isosorbide at this time was 57%.

Comparative Example 1

(37) A reaction was carried out as in Example 1 except that an H-type mordenite zeolite (manufactured by Clariant Catalysts (Japan) K.K., Si/Al=45) was used. The yield of isosorbide was 3%.

Comparative Example 2

(38) A reaction was carried out as in Example 1 except that H-type ZSM-5 (Si/Al=40) was used. The yield of isosorbide was 27%.

Comparative Example 3

(39) A reaction was carried out as in Example 1 except that an H-type Y zeolite (manufactured by Clariant Catalysts (Japan) K.K., HUSY, Si/Al=40) was used. The yield of isosorbide was 22%.

Comparative Example 4

(40) A reaction was carried out as in Example 1 except that H-BEA-35 (manufactured by Clariant Catalysts (Japan) K.K., H-type zeolite, Si/Al=17.5) was used. The yield of isosorbide was 15%.

Comparative Example 5

(41) A reaction was carried out as in Example 1 except that Nafion-Silica (manufactured by Sigma-Aldrich) that was a cation exchange resin was used. The yield of isosorbide is 66%. Due to the carbon deposition, the catalyst became black and couldn't regenerate for reuse.

Comparative Example 6

(42) A reaction was carried out as in Example 1 except that a sulfuric acid that was a homogeneous catalyst was used. The yield of isosorbide was 61%.

(43) The experimental results of Examples 1 to 4, Example 6, and Comparative Examples 1 to 6 are shown together in Table 2. In addition, the experimental results of Example 5 are shown in Table 3.

(44) As can be seen from Table 2, with the catalyst of the present invention (H-BEA-150), a conversion efficiency of almost 100% and a high selectivity of 67% were obtained in the reaction at 140 C. for 1 hour. In the reaction at 120 C., lower than 140 C., a high isosorbide selectivity value of 74% was obtained in 5 hours.

(45) In addition, Table 3 shows that under the reaction conditions of 120 C. and 5 hours, a practical high yield of 60% or more is obtained. The catalyst can be reused at least four times after regeneration.

(46) TABLE-US-00002 TABLE 2 Experimental Results of Examples 1 to 4, Example 6, and Comparative Examples 1 to 6 Yield (%) Time Catalyst 1,4- 2,5- (hr) Name Si/Al Isosorbide Sorbitan Mannitan Others Sorbitol Example 1 2 H-BEA-50 25 65 6 3 26 0 (130 C.) Example 2 0.5 H-BEA-150 75 17 36 1 11 35 (130 C.) 1 H-BEA-150 75 40 27 2 19 12 1.5 H-BEA-150 75 62 12 2 22 2 2 H-BEA-150 75 68 5 2 24 1 3 H-BEA-150 75 68 2 2 28 0 4 H-BEA-150 75 68 1 2 29 0 Example 3 0.5 H-BEA-150 75 42 24 2 21 11 (140 C.) 1 H-BEA-150 75 67 6 3 23 1 1.5 H-BEA-150 75 68 2 3 27 0 2 H-BEA-150 75 65 1 3 31 0 3 H-BEA-150 75 62 1 2 35 0 4 H-BEA-150 75 59 1 2 38 0 Example 4 1 H-BEA-150 75 14 36 1 9 40 (120 C.) 2 H-BEA-150 75 32 32 2 19 15 3 H-BEA-150 75 58 16 2 22 2 4 H-BEA-150 75 68 7 2 22 1 5 H-BEA-150 75 74 1 2 23 0 7 H-BEA-150 75 70 1 2 27 0 8 H-BEA-150 75 70 1 2 27 0 Example 6 2.5 H-BEA-150 75 57 19 3 19 2 (140 C.) Comparative 2 HMOR 45 3 12 1 8 76 Example 1 Comparative 2 HZSM-5 40 27 9 1 17 46 Example 2 Comparative 2 HUSY 40 22 30 9 29 10 Example 3 Comparative 2 H-BEA-35 17.5 15 23 1 5 52 Example 4 Comparative 2 Nafion 66 9 4 23 0 Example 5 Comparative 2 H.sub.2SO.sub.4 61 13 4 22 0 Example 6

(47) TABLE-US-00003 TABLE 3 Experimental Results of Example 5 Yield (%) Number of Catalyst 1,4- 2,5- reactions Name Si/Al Isosorbide Sorbitan Mannitan Others Sorbitol Example 5 First H-BEA-150 75 74 1 2 23 0 (120 C., 5 repetition hours) Second H-BEA-150 75 71 1 2 26 0 recovery, repetition repeated Third H-BEA-150 75 66 6 2 26 0 use repetition Fourth H-BEA-150 75 62 10 2 25 1 repetition

Example 7

(48) A reaction was carried out as in Example 2 except that the pressure was reduced to 700 hPa, and stirring was performed by a stirring bar. The isosorbide yield after 4 hours of reaction was 74%, an increase compared with 68% in Example 2.

Example 8

(49) A reaction was carried out as in Example 3 except that the pressure was reduced to 700 hPa, and stirring was performed by a stirring bar. The isosorbide yield after 1 hour of reaction was 70%, an increase compared with 67% in Example 3.

Example 9

(50) A reaction was carried out as in Example 4 except that the pressure was reduced to 700 hPa, and stirring was performed by a stirring bar. The isosorbide yield after 7 hours of reaction was 73%, an increase compared with 70% in Example 4.

(51) The experimental results of Examples 7 to 9 are shown in Table 4. By reducing pressure and stirring, the yield of isosorbide can be increased. Therefore, the dehydration reaction of sorbitol was tested again under this reduced pressure condition by varying not only the catalysts but also the amounts.

(52) TABLE-US-00004 TABLE 4 Experimental Results of Examples 7 to 9 Yield (%) Reaction Catalyst 1,4- 2,5- time (h) Name Si/Al Isosorbide Sorbitan Mannitan Others Sorbitol Example 7 0.25 H-BEA-150 75 7 31 1 9 53 (130 C.) 0.5 H-BEA-150 75 24 39 2 13 25 1 H-BEA-150 75 50 25 1 21 5 2 H-BEA-150 75 71 5 3 23 1 4 H-BEA-150 75 74 2 2 24 1 6 H-BEA-150 75 74 2 2 24 0 Example 8 0.5 H-BEA-150 75 56 18 3 23 3 (140 C.) 1 H-BEA-150 75 70 2 3 25 0 2 H-BEA-150 75 72 2 3 26 0 4 H-BEA-150 75 73 1 2 26 1 Example 9 1 H-BEA-150 75 22 38 1 14 26 (120 C.) 2 H-BEA-150 75 46 28 1 22 4 5 H-BEA-150 75 71 3 2 25 2 7 H-BEA-150 75 73 3 3 25 0

Example 10

(53) A reaction was carried out as in Example 7 except that the amount of the catalyst used was 12.5 mg. The yield of isosorbide after 2 hour of reaction was 23%.

Example 11

(54) A reaction was carried out as in Example 7 except that the amount of the catalyst used was 25 mg. The yield of isosorbide after 3 hour of reaction was 51%.

Example 12

(55) A reaction was carried out as in Example 7 except that the amount of the catalyst used was 37.5 mg. The yield of isosorbide after 2 hours of reaction was 62%.

Example 13

(56) A reaction was carried out as in Example 7 except that the amount of the catalyst used was 75 mg. The yield of isosorbide after 2 hours of reaction was 72%.

Example 14

(57) A reaction was carried out as in Example 7 except that the amount of the catalyst used was 100 mg. The yield of isosorbide after 2 hours of reaction was 70%.

Example 15

(58) A reaction was carried out as in Example 7 except that the pressure was <10 hPa. The yield of isosorbide after 2 hours of reaction was 75%.

Example 16

(59) A reaction was carried out as in Example 7 except that the pressure was 350 hPa. The yield of isosorbide after 2 hours of reaction was 72%.

Example 17

(60) A reaction was carried out as in Example 7 except that the pressure was 1000 hPa. The yield of isosorbide after 2 hours of reaction was 71%.

Example 18

(61) A reaction was carried out as in Example 7 except that H-BEA-50 (H-type zeolite, Si/Al=25) calcined at 550 C. for 8 hours was used. The yield of isosorbide after 2 hours of reaction was 68%.

Comparative Example 7

(62) A reaction was carried out as in Example 7 except that H-BEA-25 (manufactured by Clariant Catalysts (Japan) K.K., H-type zeolite, Si/Al=12.5) calcined at 550 C. for 8 hours was used. The yield of isosorbide after 2 hours of reaction was 41%.

Comparative Example 8

(63) A reaction was carried out as in Example 7 except that H-BEA-35 (H-type zeolite, Si/Al=17.5) calcined at 550 C. for 8 hours was used. The yield of isosorbide after 2 hours of reaction was 51%.

Comparative Example 9

(64) A reaction was carried out as in Example 7 except that an H-type ZSM-5 zeolite (Si/Al=12.5) was used. The yield of isosorbide after 2 hours of reaction was 9%.

Comparative Example 10

(65) A reaction was carried out as in Example 7 except that an H-type ZSM-5 zeolite (Si/Al=45) was used. The yield of isosorbide after 2 hours of reaction was 27%.

Comparative Example 11

(66) A reaction was carried out as in Example 7 except that an H-type Y zeolite (Si/Al=2.6) was used. The yield of isosorbide after 2 hours of reaction was 0%.

Comparative Example 12

(67) A reaction was carried out as in Example 7 except that an H-type Y zeolite (Si/Al=15) was used. The yield of isosorbide after 2 hours of reaction was 2%.

Comparative Example 13

(68) A reaction was carried out as in Example 7 except that an H-type Y zeolite (Si/Al=40) was used. The yield of isosorbide after 2 hours of reaction was 22%.

Comparative Example 14

(69) A reaction was carried out as in Example 7 except that an H-type mordenite (Si/Al=45) was used. The yield of isosorbide after 2 hours of reaction was 3%.

Comparative Example 15

(70) A reaction was carried out as in Example 7 except that a sulfuric acid was used. The yield of isosorbide after 2 hours of reaction was 69%.

(71) The experimental results of Examples 10 to 18 and Comparative Examples 7 to 15 are shown in Table 5. In addition, results obtained by plotting the isosorbide yield after 2 hour of the reaction in Examples 7 and 18 and Comparative Examples 7 to 14 with respect to the Si/Al ratio are shown in FIG. 3. It is seen that the H-type zeolites having an Si/Al ratio of more than 20 specifically provide isosorbide with a high yield.

(72) TABLE-US-00005 TABLE 5 Experimental Results of Examples 10 to 18 and Comparative Examples 7 to 15 Amount of Yield (%) Reaction Pressure Catalyst catalyst 1,4- 2,5- time (h) (hPa) Name Si/Al (mg) Isosorbide Sorbitan Mannitan Others Sorbitol Example 10 2 700 H-BEA-150 75 12.5 23 36 2 11 29 Example 11 2 700 H-BEA-150 75 25 51 27 3 15 4 Example 12 2 700 H-BEA-150 75 37.5 62. 15 3 18 2 Example 13 2 700 H-BEA-150 75 75 72 2 3 24 0 Example 14 2 700 H-BEA-150 75 100 70 2 2 26 0 Example 15 2 <10 H-BEA-150 75 50 75 2 3 19 2 Example 16 2 350 H-BEA-150 75 50 72 2 3 23 0 Example 17 2 1000 H-BEA-150 75 50 71 3 3 22 1 Example 18 2 700 H-BEA-50 25 50 68 6 3 20 3 Comparative 2 700 H-BEA-25 12.5 50 41 30 3 16 11 Example 7 Comparative 2 700 H-BEA-35 17.5 50 51 21 3 18 7 Example 8 Comparative 2 700 HZSM-5 12.5 50 9 6 0 13 73 Example 9 Comparative 2 700 HZSM-5 45 50 27 7 1 15 50 Example 10 Comparative 2 700 HY 2.6 50 0 0 0 0 100 Example 11 Comparative 2 700 HY 15 50 2 9 2 15 7 Example 12 Comparative 2 700 HY 40 50 22 20 7 43 8 Example 13 Comparative 2 700 HMOR 45 50 3 14 1 7 77 Example 14 Comparative 2 700 H.sub.2SO.sub.4 1.1 69 3 4 24 1 Example 15