JPS61212592A - Production of d-ribose - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high yield, by carrying out the epimerization of D-arabinose using a molybdic acid compound as a catalyst in the presence of a boric acid compound, and treating the reaction liquid with a column of a metal-type cation exchange material. CONSTITUTION:D-arabinose used as the starting raw material is epimerized by heating preferably at 50-100 deg.C in water, organic solvent or hydrous organic solvent in the presence of a molybdic acid compound (preferably a VI-valent compound) and a boric acid compound. The obtained reaction liquid is passed through a column packed with a 2- or 3-valent metal-type cation exchange material (preferably polystyrenesulfonic acid-type strongly acidic ion exchange resin converted to Ca-type, etc.) and eluted usually with water to separate the objective compound. The amount of the boric acid compound is preferably 1.5-3mol per 1mol of the raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing D-ribose. More specifically, D-arabinose is subjected to an epimerization reaction in the presence of a molybdate compound and a boric acid compound I) +
This invention relates to a method for producing ribose in high yield.

Conventional technology Conventionally, the method for producing D-ribose is as follows.

A method of extracting from natural products, a fermentation method using microorganisms.

Chemical synthesis methods are known.

As a chemical synthesis method, D-glucose is oxidized with oxygen to form D
- Araponic acid is converted into D-ribonic acid under alkaline conditions, and then converted into D-ribonolactone, which is then reduced with sodium amalgam to obtain D-ribose, which has been commonly carried out industrially. On the other hand, several methods are known in which ribose is obtained by epimerizing arabinose in an aqueous solution using a molybdate compound as a catalyst. for example.

Czechoslovakia Patent No. 149472 (Chemical Apstrak vol. 81.78189, 1974) describes L-arabinose with an epimerization rate of about 33%.
JP-A-55-164699 describes a method for obtaining D-ribose from D-arabinose with an epimerization rate of about 25%. Furthermore, in order to simplify the separation of molybdic acid in the aqueous reaction solution, a method using an ion exchange resin or ion exchange fiber carrying molybdic acid in place of the molybdic acid compound has been proposed in JP-A-55-76894 and JP-A-57-57. It is disclosed in No. 54197 and No. 57-54198, and the epimerization rate from D-arabinose to D-ribose is 30.6%.

Approximately 25 to 30 inches, 25.1 inches.

Several methods of separating sugar solutions using divalent or trivalent metal cation exchangers are known, for example,
No. 25600 describes a method of introducing an aqueous high-fructose solution into a strongly acidic cation exchange resin such as a calcium type, strontium type, or barium type to separate it into a fructose aqueous solution and a glucose aqueous solution. 5.7-541
No. 98 describes a reaction solution in which D-arabinose was epimerized in the presence of molybdate ions, that is, D-ribose (2
5,1-28.0ch)t D-arabinose (66,
4 to 72.2 h), D-xylose and D-rifusauce (
A method of separating D-lipose by passing an aqueous solution containing 0.6 to 1.8%) through a calcium-type, barium-type, strontium-type, aluminum-type, etc. cation exchange resin column is also disclosed in JP-A No. No. 55'-164699 discloses a mother liquor obtained by removing most (70%) of unreacted D-arabinose and inorganic substances from a reaction solution obtained by ebimerizing D-arabinose under a molybdic acid catalyst, that is, D-ribose (
approximately 70%).

A hydroalcoholic solution containing D-arabinose (10%), D-xylose and D-rifose (10%) and other sugar by-products (10%) was prepared on a cation exchanger loaded with calcium or barium ions. A method for obtaining D-ribose by chromatography is disclosed. others.

Method for separating ribose and arabinose using a strongly basic anion exchange resin in the borate form (J.

Am, Chem, Soc, 73. 2399 (195
1) ;Same-B”.

2090 (1952)) is also known. A method for separating boric acid or borate-containing sugar solutions is a method using a hydrogen sulfite type or sulfite type anion exchanger (Japanese Patent Publication No. 52
-9740) is known.

Problems to be Solved by the Invention In the conventional method of obtaining D-ribose by epimerizing an aqueous solution of D-arabinose under the catalyst of a molybdate compound,
The epimerization rate is at most 20 to 30%, which is insufficient for industrial implementation, and a higher yield of epimerization is desired.

[Structure of the invention]

Means and Effects for Solving the Problems The present inventors have solved the problem by heating D-arabinose in water, an organic solvent, or a water-containing organic solvent in the presence of a molybdate compound, and then adding a boric acid compound to the mixture. ~94%
In particular, when an organic solvent is used, I) + IJ bose is produced with an amazing ebimerization rate of about 90-94%, and in addition, a high content of D-ribose, a small amount of unreacted D-arabinose, and a trace amount of by-products are produced. D-xylose and D-rifusauce.

The present inventors discovered that pure mono-ribose could be obtained in high yield by passing a reaction solution containing a molybdate compound and a boric acid compound through a column packed with a metal-type field ion exchanger, and completed the present invention. .

The method of the present invention is a very advantageous industrial method because D-ribose can be obtained from D-arabinose in high yield.

Next, the method of the present invention will be specifically explained.

D-arabinose to D-arabinose 0.5~
It is added to 3.0 times the amount (W/v) of water, an organic solvent, or a water-containing organic solvent, and 1 to 10% (w/v) of D-arabinose is added as molybdate ion to the resulting solution or suspension.
w) Add the molybdic acid compound.

Further, 0.5 to 5.0 times mole, preferably 1.5 to 3 times mole of a boric acid compound is added to D-arabinose.
Stir for 30-60 minutes at a reaction temperature of 0-120G, preferably 50-100t:'.

In addition to water, the solvents used are methanol, ethanol, n-7' lovanol, and isopronophenol.

n-butanol, isobutanol, 5ec-butanol tert-butanol, n-7 mil alcohol.

In-amyl alcohol, 5ec-amyl alcohol.

n-hexanol, methyl amyl alcohol, 2-ethyl-hexanol, cycloxanol.

Ethylene glycol, diethylene glycol, furopylene gelicol, ethylene glycol monomethyl ether (Methyl Serotsuru 7'), diethylene glycol heptanoethyl ether (Calpitol).

Alcohols such as diethylene glycol monomethyl ether (methylcarpitol), acetone.

Methylacetone, methylethyl, ketone, dioxane,
Hyridine, α-picoline, 2,6-lutidine.

Acetonitrile, N,N-dimethylformamide (D
MF), N,N-dimethylacetamide (DMA),
Organic solvents such as dimethyl sulfoxide (DMSO) or water-containing solvents thereof.

The molybdic acid compounds used include molybdic acid,
Examples include ammonium molybdate, potassium molybdate, sodium molybdate, calcium molybdate, and acetylacetone molybdate, and compounds with a valence of molybdenum are particularly preferred. Further, an ion exchange resin or ion exchange fiber carrying molybdic acid may be used.

The boric acid compounds used include boric acid, boron oxide,
Methyl borate, ethyl borate, ammonium borate, potassium borate, sodium borate.

Examples include phenylboric acid. When using a boric acid ester or a boric acid salt, the - of the reaction solution is adjusted to 1 to 5. Preferably it is adjusted to 3 to 3.5. Further, when an anhydrous organic solvent is used as one reaction solvent, boric acid is particularly suitable.

When the reaction solution obtained in this manner is cooled, a portion of the boric acid compound precipitates, and by removing this, the burden of post-treatment can be reduced. The recovered boric acid compound can be used again in the reaction.

Further, the boric acid compound can be removed by a known method such as an azeotropic removal method using a lower alcohol or treatment with a weakly basic anion exchange resin, if necessary. However, one of the features of the method of the present invention is that it is simple because it can be used for the next purification treatment simply by cooling one reaction solution and removing a portion of the precipitated amount.

When this D-ribose-containing reaction solution is used as a raw material for riboflavin synthesis, the catalysts are removed using an anion exchange resin without isolating l)-ribose because the D-ribose content in the solution is high. 4-Nitro-O-
catalytic reduction in the presence of 1-D-sabithyl-3, silene or 3,4-xylidine, and crystallization of the resulting mixture
4-xylidine is obtained, which is subjected to a coupling reaction with a diazonium salt solution and then condensed with norbituric acid.

In the above reaction solution]) + IJ Bose t1 force 1
It contains unreacted D-arabinose, by-products D-xylose and D-lyxose, a molybdate compound, and a boric acid compound, and other raw materials used may also contain ions and by-products.

This reaction solution is passed through a column packed with a divalent or trivalent metal cation exchanger, and dissolved with water. The elution order is molybdate compound, boric acid compound, D-xylose and I) + 17 xose D-arabinose,
The elution distribution map is shown in Example J in FIG. 1 based on Example 1.

Further, the elution distribution diagram of the reaction solution after removing the molybdic acid compound with an anion exchange resin is illustrated in FIG. 2 based on Example 91j3.

As the divalent or trivalent metal type cation exchanger, polystyrene sulfonic acid type strongly acidic ion exchange resins in the form of calcium type, barium type, strontium type or aluminum type can be suitably used.

The fractionated solution of D-arabinose contains a boric acid compound and a molybdic acid compound, so if the solution is concentrated to a certain concentration and heated, the epimerization reaction can be performed again.
The yield of ribose is further improved. Another feature of this method is that the fractionated solution of the molybdate compound contains almost no impurities, so it can be used again for the reaction.

The D-ribose fraction that elutes most slowly is collected and concentrated under reduced pressure to obtain a D-ribose syrupy residue with a recovery rate of 95% or more. By crystallizing this residue with methanol or ethanol, D-ribose crystals with a purity of 99.5% or higher can be obtained.

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

Ru.

In Example 1, the composition and crystallization of sugar in the reaction solution and the purity of ribose were determined by reducing the sugar with sodium borohydride to obtain the corresponding sugar alcohol. I measured it carefully. Further, quantitative analysis of molybdate compounds and boric acid compounds was carried out by measuring the former by chelate titration and the latter by neutralization titration.

In addition, in the examples, the ion exchange resin used
MK-318, 5x-IB, and WA-301df are all product names manufactured by Mitsubishi Chemical Corporation.

Example 1 D-7 Rabinose 25? Add 50ml 1K of ethanol,
Furthermore, 1.75 F of ammonium molybdate and 25.89 F of boric acid were added, and the reaction temperature was 88 C (the temperature inside the reaction vessel was higher than the boiling point of ethanol).

) for 45 minutes with stirring. After the reaction was completed, the solvent was distilled off under reduced pressure, and 50 t# of water was added to the residue, followed by stirring.

After cooling to 10C, the precipitated boric acid was separated. The crystals were washed with cold water and dried to recover boric acid 20.59-.

When the r solution and washing solution were combined, the result was 110 stJ.

The composition of sugar in this solution was as follows.

D-ribose 90.5% D-acybinose 7.7% D-xylose and D
-Recounse and others 1.8% Strongly acidic cation exchange resin Diaion MK-318 in which this solution was exchanged to calcium type
Pass the solution through a column packed with 510at/, elute with water,
The eluate was fractionated into 10 d portions using a fraction collector. The flow rate was 68++ Lg/hr.

The elution order is molybdenum, boric acid, D-xylose and D-
They were Lyxose, D-arabinose, and D-ribose (see Figure 1). The total amount of eluate was 10,103 O, of which 7 was the D-ribose fraction. Comb: l7Nn4
3-103(7)610. lIl, 7 lactation rI&L25-42 as D-arachinose boric acid fraction
18oR1, fraction l' as molybdenum fraction
140++/ of &11 to 24 were collected respectively. D-
The ribose fractions were combined and the solvent was dried under reduced pressure to obtain a syrup residue 23.19-. Add 40m of ethanol to this residue/
When added and left in the refrigerator overnight, crystals precipitated, so P was removed and dried to obtain D-ribose crystals of 20.4 P (81
, 6chi) were obtained. Melting point 86 tl'o ('')p -1
8.4° (C=1.0.water). Purity 99.7%.

Furthermore, the D-7 ravinose/boric acid fraction was concentrated under reduced pressure to form a syrup, and then 511 tons of ethanol was added to it for 90 minutes.
The mixture was heated under stirring at 1Z' for 40 minutes. After reaction.

Water 10! Itl was added and cooled for 6CK, and the precipitated boric acid was separated and washed. A solution obtained by combining the R solution and the washing solution was subjected to chromatographic separation, crystallization, etc. in the same manner as above to obtain D-ribose crystals tasP(s, sti). Melting point: 86.0C9° Purity: 99.8C. The total yield was 87.
It was 1ch.

In addition, the amount of molybdenum and boric acid in the molybdenum fraction and arabinose/boric acid fraction is 0.9y as molybdenum.
-, 5.1 as boric acid? We were able to quantitatively recover the contained waste.

Example 2 D-arabinose 20? was added to 40ffi/methanol, and then 1.5% of ammonium molybdate was added. and 20.6 i of boric acid were placed in an autoclave and heated at 88C for 40 minutes with stirring. After the reaction was completed, the reaction solution was removed from the autoclave and the solvent was distilled off under reduced pressure.

50 sl of water was added to the residue, stirred, and left in the refrigerator overnight. The precipitated boric acid was separated from P and washed with 35 d of cold water.
Boric acid 16F was recovered by drying. When the R solution and the washing solution were combined, 92d was obtained, and the sugar composition in this solution was as follows.

D-ribose 87.8% D-arabinose 10.4% D-xylose and D
- 1.7% of ref sauce, etc. Add methanol 35ml to this solution
The solution was passed through a column packed with a strongly acidic cation exchange resin, Diaion MK-318510xl, which had been converted into a calcium form by the addition of 100% chloride, and eluted with water at a flow rate of 75 td/hour.

The eluate was fractionated into 15 d portions to obtain a total volume of 990 txl.

Of these, the D-ribose fraction was 450 yxl, and the D-arabinose boric acid fraction was 210 ml. Molybdenum fraction 240d
Met.

The D-ribose fractions were combined and the solvent was dried under reduced pressure. 20 ml of ethanol was added to the resulting syrup residue (17.2 F) and left in the refrigerator overnight. The precipitated crystals were collected and dried. D-ribose crystal 15. IP (75,5%) was obtained. Melting point: 86.5C'0 Purity: 99°Next, the arabinose/boric acid fractions were combined and concentrated under reduced pressure, and 5 txl of isopropanol was added and reacted for 60 minutes with stirring at a reaction temperature of 88C. After the reaction is complete.

The solvent was distilled off under reduced pressure, 30 txl of water was added, and the mixture was cooled to 4°C.

The precipitated boric acid was separated and washed. The total amount of R solution and washing solution was 40 d, and the sugar composition in this solution was as follows.

D-y hose 73.21 D-7 ravinose 15.3% D-Musylose, D-refuse, etc. 11.4% This solution was subjected to chromatographic separation, crystallization, etc. according to the same method as above to obtain D- Ribose crystals of 1°34F (6,7C) were obtained.

Melting point 86.2G, purity 99.8G.

The total yield was 82.2%.

Example 3 Add 251 D-arabinose to 45 ml of dioxane,
In addition, ammonium molybdate 1.8y- and boric acid 30? was added and heated at 90C for 40 minutes with stirring. Then, by the same operation as in Example 1, boric acid 23.89-
was collected to obtain an aqueous solution with a liquid volume of 78 g. The composition of sugar in this solution was as follows.

D-ribose 94.2% D-arabinose 4.9% D-xylose t! −
D-! Free Kl! i
Molybdic acid was removed by using a conditioned styrene-based weakly basic anion exchange resin DIAION WA-30 for 20 hours. This treated solution was concentrated under reduced pressure to 80ffi/, and the strongly acidic cation exchange resin Diaion M was exchanged into a calcium type.
The liquid was passed through a column packed with K-318510m/ and was continuously eluted with water to fractionate each 12xl (see Figure 2).
.

The flow rate was 9811 Ll/h. The total volume of eluate is 96
0ml, of which 600t/31 to 80 fractions as D-ribose fraction, D-arabinose.
Fraction 14 to 30 204 as boric acid fraction
Go was separated.

The sugar composition in the I)-17 fraction was 99.2% D-ribose and 0.8% D-arabinose and others.

This solution was dried under reduced pressure, 35xtl of ethanol was added, and the mixture was left in the refrigerator overnight, and the precipitated crystals were collected.

Dried D-ribose crystals 20.8p (83.2chi)
I got it. Melting point: 86.4C, purity: 100%.

Example 4 D-arabinose 10P was added to 25 m/25% hydrated isochrononol, and ammonium molybdate o,
sy- and 12.6y- of boric acid were added and heated at 90G for 50 minutes with stirring. Next, 9.5y- of boric acid was recovered by the same operation as in Example 1, and an aqueous solution with a liquid volume of 45++t/ was obtained. The composition of sugar in this solution was as follows.

D-lyt:-89.5% D-arabinose 8.2% D-xylose,! :D-! Strongly acidic cation exchange resin 5K- in which this solution was exchanged into a calcium type with 2.2% of Jri, sauce, etc.
The solution was passed through a column packed with 1000 ml of IB and eluted with water at a flow rate of 200 m67 hours. 15 eluate
d fraction, and the molybdenum fraction was 450 ml. D-arabinose bottle boric acid fraction 39 (ltl, D-ribose fraction 9
00 ml was collected.

The sugar composition in the D-ribose fraction is f)-ribose 9
8.7%, D-7 ravinose 0.8%, other 0.5%
Met.

This solution was dried under reduced pressure and crystallized with 15 mA' of ethanol to obtain 7.67 (76%) crystals of D-ribose. Melting point: 86C; purity: 99.8C.

Example 5 D-arabinose 209- was added to 15 m/ml of water, and 2.1 ml of sodium molybdate was added. and methyl borate 28
? was added, the p) was adjusted to 13.2 with acetic acid, and the mixture was heated at 93C for 50 minutes with stirring. After completion of reaction 1 reaction solution K 20 t water
rtl was added and cooled to 10C. The precipitated boric acid is
After washing with water, 13.2y- of boric acid was recovered. The composition of sugar in 60 mJ of the combined solution of R solution and washing solution was as follows.

D-ribose 69.8% D-arabinose 27.8% D-xylose and D
- 2.4% of refsauce and other
The solution was passed through a column packed with 500x water and eluted with water while maintaining the temperature inside the column at 40C. The flow rate is 70a
t/hour. Modify the eluate 1) Buden fraction 240rn
1. D-arabinose boric acid fraction 190mg, D+
The IJ port fraction was fractionated into 1@ of 450 rug.

The sugar composition of the D-IJbose fraction is D-ribose 9
8.2%, D-arabinose 1.2%, and 0.
It was 5chi.

This solution was dried under reduced pressure to obtain a syrup residue 13.7ii1-
was obtained, and 15 m/ml of ethanol was added to it to crystallize it.

P is removed and dried to give D-lJ&-s crystals tt4y (57
h) was obtained. Melting point: 86.2C, purity: 99.5C.

Example 6 D-7 ravinose 601 was added to dioxane 110++t#, and further ammonium molybdate 4.8y- and boric acid 61.8P were added and reacted at 88.C for 45 minutes. Then, by the same operation as in Example 1, boric acid 48.
2F was collected to obtain an aqueous solution with a liquid volume of 210 ml. The composition of sugar in this solution was as follows.

D-ribose 93.4% D-arabinose 5.8% D-xylose and D
- 0.7% of refsauce etc. Strongly acidic cation exchange resin Diaion MK-318 in which this solution was exchanged to calcium type
The solution was passed through a column packed with 1500 g of water and eluted with water at a flow rate of 285 m67 hours. The separated D-ribose fractionated liquid 1080+t/was dried under reduced pressure to obtain a syrup residue of 56
．． 651- was obtained. This was crystallized from 80 ml of ethanol to obtain 51.6 p (86 p) of D-ribose crystals.

On the other hand, the sugar content in D-arabinose/boric acid fraction 480R/ is 85.4% D-arabinose.

It contained 11.4 p of D-xylose, D-liquose, and 3.2 p of D-lipose, and further contained 10.2 p of boric acid. Furthermore, 555 rttl of the molybdenum fraction contained 2.4y- of molybdenum and 3.2y- of boric acid.

The D-arabinose/boric acid fraction was concentrated under reduced pressure to form a syrup, and ammonium molybdate 0.1% was added to the syrup. and dioxane 5d were added, and the mixture was heated and stirred at 88C for 45 minutes. After the reaction was completed, water 50III7 was added, cooled for 10CK, and the precipitate was separated.The sugar content in the liquid was D-ribose 78.7%, D-arabinose 11.5%, D-xylose, and D-rifose. Others accounted for 10.8%.

This solution was subjected to chromatographic separation by the same method as above.
Crystallization is performed to obtain D-ribose crystals of 1°6Lf (2,
6chi) was obtained. Melting point 86.4%. 100% purity.

The total yield was 88.6%.

Example 7 155 L of D-arabinose was added to 40 txl of hydrated ethylene glycol, 3'1 i of methyl borate was added, and the - was adjusted to 3.3 with dilute sulfuric acid. 1.2 i of ammonium molybdate was added thereto and stirred at 90C for 40 minutes. After the reaction was completed, the reaction solution was cooled to IOC, the precipitate was separated, and the crystals were washed with 25 d of cold water. The r liquid was concentrated under reduced pressure to remove the solvent, and then 50 txl of water was added. The composition of sugar in this aqueous solution was as follows.

D-ri M-y, 90.2'1rD
-Arabinose 7.3% D-xylose, D-refuse, etc. 2.5% This solution was passed through a column packed with a strongly acidic cation exchange resin Diaion MK-318500, which had been exchanged with strontium, and then diluted with water. Elution was performed, and the eluate was fractionated into 10 d portions. l) -
I) The fractionated solutions of bose were collected and dried under reduced pressure, and the resulting syrup residue was crystallized with 20 m/m of ethanol, P was removed, and dried to obtain D-ribose crystals ii, sy (7 g, 7%). Obtained.

Melting point ss, 8tl', purity 99.7chi Example 8 D-arabinose 15? was added to 20 mj of water, and then sodium borate (Na, B, O, -10H, O) 57
Add ゜21 and molybdic acid (son) x, 5F.

The resulting aqueous solution was adjusted to pH 3.2 with dilute sulfuric acid and heated at 92C.
The mixture was heated and stirred for 40 minutes. After the reaction was completed, the reaction solution was cooled to 8C, and the precipitated boric acid and sodium sulfate were separated.
The R liquid is strongly acidic cation exchange resin Diamond 5K-
It was desalted by treatment with IB.

After concentrating the treated solution under reduced pressure to 60%, the sugar composition was determined as follows.

D-Ribose 68.5% D-7 Rabinose 29.1% D-xylose and D
-2.4% of refsauce, etc. Strongly acidic cation exchange resin Diaion MK-31 in which this solution was exchanged into an aluminum mold
The liquid was passed through a column packed with 8500rnl, and the flow rate was 88a.
At 11 o'clock, the eluate was eluted with water, and the eluate was fractionated into 10 rnl portions.

The D-ribose fractions were combined, dried under reduced pressure, and crystallized from ethanol to give D-ribose crystals of 9.17 (60
, 6%). Melting point: 86C; purity: 99.5C.

When a D-ribose-containing solution is used for the synthesis of riboflavin, the procedure is as follows.

Reference Example D - 16.0p of arabinose was added to 30ytl of dioxane, ammonium molybdate x, tsy and boric acid 18.51i1- were added, and the mixture was heated and stirred at 88C for 45 minutes. The composition of sugar in the solution after removing boric acid by the same operation as in the above example was as follows.

D-ribose 92.5% D-arabinose 6.4% D-xylose and D
- Refuse and others 1.1% This solution was treated with 12 txt of weakly basic anion exchange resin DIAION WA-30 to remove molybdic acid. This solution was concentrated until the sugar concentration was about 50% and placed in a 500-liter autoclave.

Furthermore, methanol 230st#, 3,4-xylidine 1
2.6f, acetic acid 0.3 txt, sodium acetate 0.4
).

Add Raney nickel 9.0) (hydrated) and fill with hydrogen.
The mixture was stirred at 60C for 80 minutes. After the completion of the reaction, Raney nickel was separated from the reaction solution 9, and solution F was concentrated to about 200d, and upon cooling, crystals were precipitated. Take this crystal, 50
Recrystallize with timeethanol to obtain 1-D-ribityl-3.4-
Crystals of lysine (24.4) (89.7%) were obtained.

Melting point 145C, (α°] D-21,8° (C=0.4.
Methanol) The thus obtained 1-D-riviter-3,4-xylidine is subjected to a coupling reaction with a diazonium salt solution according to a conventional method, and then condensed with barbylic acid to obtain ribo-7-).

〔Effect of the invention〕

The conventional epimerization reaction of D-arabinose was carried out in a water solvent using a molybdic acid compound as a catalyst, and the rate of epimerization to D-ribose was about 20 to 30%.

The method of the present invention improves the shear vimerization rate to about 70 to 94 cm by adding a boric acid compound to the conventional method and further using water #1, an organic solvent, or a water-containing organic solvent as a solvent. was completed.

In particular, when an organic solvent is used as a solvent, about 90 to 94%
It showed an astonishing rate of ebimerization.

Subsequently, this reaction solution was subjected to column chromatography once using a strongly acidic cation exchange resin exchanged with calcium type, barium type, strontium type, or aluminum type, with a recovery rate of 99% or more. .5%
It is possible to obtain D-ribose with a high purity as described above. Furthermore, unreacted D-7 ravinose was recovered by chromatographic separation.

Molybdenum and boric acid also have the advantage that they can be reused.

Therefore, the method of the present invention can produce D-ribose in extremely high yield, and is therefore a very useful method industrially.

[Brief explanation of drawings]

Figure 1 is an elution distribution diagram of Example 1 of the method of the present invention. FIG. 2 is an elution distribution map of Example 3. ■---- D-ribose fraction 0----1 D-arabinose fraction ■----D-=? Gilost D-
Fractionation of Lyxose 0-111 Boric acid fraction■---
− Moripde/fraction

Claims (2)

[Claims] (1) D-arabinose and a molybdate compound are added to water, an organic solvent, or a water-containing organic solvent, and a boric acid compound is further added to conduct an epimerization reaction under heating. D, characterized in that D-ribose is separated by passing the liquid through a column of a metal-type cation exchanger.
- A method for producing ribose. (2) The manufacturing method according to claim (1), wherein the metal of the metal-type cation exchanger is calcium, barium, strontium, or aluminum.