SU1391494A3 - Method of producing xylite - Google Patents

Abstract

1454697 Pentitols from pentose rich hydrolysates SHOMEN SOKERI OSAKEYHTIO 18 April 1974 [25 April 1973] 16912/74 Heading C2C Polyols are obtained from pentose-rich pentosan hydrolysate solutions by filtering off suspended solids, removing inorganic salts and a major part of the organic impurities by ion exclusion; removing the remaining organic impurities with an ion exchange resin or activated carbon; fractionating the solution by ionexchange chromatography to give a pentose solution having a high xylose content; hydrogenating the solution to form a polyol solution; and fractionating the latter to give highly pure polyol fractions, free of unreduced sugars and other impurities. The final step of the process is preferably carried out by supplying the polyol solution to polystyrene sulphonatedivinylbenzene resin in a salt form and successively separating an unhydrogenated sugar fraction containing other impurities and a substantially pure polyol fraction.

Description

The invention relates to a method for producing xylitol from pentosan-containing materials, preferably from xnlan-containing materials, followed by purification and separation by chromatography.

The aim of the invention is to increase the yield of the target product.

Example 1. 25 kg of birch chips (containing 82% of dry matter is hydrolyzed with 50 kg of 2% sulfuric acid to produce a mixture of hydrolyzate and pulp. After hydrolysis, 41 kg of water is rinsed out of the mixture. Hydrolyzate is extracted from the hydrolyzate (72 kg) neutralize 2 kg of 40% sodium hydroxide. The neutralized hydrolyzate has the following composition

Substance Weight, kg Dry substance (rv),%

Na, S04 1.44 16.7 Xylose 4.10 47.5 Arabinose 0.16 1.8 Mannose 0.31 3.6 Galactose 0.24 2.8 Glucose 0.29 3.3 Disaccharide 0.12 1, 4 Others; 1.98 22.9 Total 8.64

44 kg of water is evaporated from the hydrolyzate and the residue is purified to remove the salt and exclude the ions; consequently, the solution is carried out through layers of strong catnon-exchange resins having the following characteristic under the following conditions

Polystyrene Sulfonate Resin

with 5.5% OBE, layer size 0.40 mm as N Column Height 5.5 m, diameter

0.225 m

Temperature, ° С 65 Raising the flow, MV4 0.05 Feed size, kg / s.v. 8.64

Get a solution containing

Weight, kg CW,%

0.040.8

3.8477.6

0,142,8

0.265.3

0,214,2

0,234,7

0.08 0.15

4.95

1.6 3.0

Q 5 0

50

five

0

five

0

five

The Sugars fraction, containing most of the xylose, undergoes purification through successive layers of the providing resin, a strong cation exchanger and a weak anion exchanger.

The cleaning is carried out using the following materials under the following conditions. Material Quantity - Bore diameter, diameter, cm. Disintegrating resin 750 5 Strong cation-exchanger 600 5 Weak anion-exchanger 750 5

After cleaning, the solution is evaporated to remove 28 kg of water. The concentrated sugar solution obtained in this way goes through another stage of bleaching.

Discoloration is carried out as follows. Material: Forged diameter, ml of lacquer, cm. Polymeric adsorbent 500 5 Granular activated carbon 500 5

The solution thus purified, containing 3.76 kg of xylose, undergoes catalytic hydrogenation in a thermostatted autoclave using Rene nickel as a catalyst at 135 ° C for 24 hours, while the hydrogen pressure is 40 atm.

The composition of the solution undergoing hydrogenation, the following Substance Weight, kg AH,% Xylose 3.76 78.3

Arabinose 0.14 2.9 Mannose 0.25 5.2 Galactose 0.21 4.4 Glucose 0.22 4.6 Disaccharides 0.08 1.7 Other 0.15 3.1 Total 4.81

After this time, the catalyst was removed by filtration, and the remaining. fine nickel and other contaminants remaining in the solution are removed by ion exchange

Substance

Mass, ml

Column diameter, cm

Chelating resin

complex 250 2.5 Strong cation. but exchanger 250 2.5 Anion exchanger 300 2.5

To the hydrogenated solution was added the mother liquor from the prior crystallization of xylitol, and the combined solution was subjected to chromatographic separation on a column with an ion exchange resin.

The solution supplied to the chromatographic separation, the following Substance Mass, kg CW,% Xylitol 5.85 74.4 Arabinite 0.61 7.6 Mannitol 0.36 4.6 Galactite 0.28 3.6 Sorbitol 0, 39 5.0 Others 0.38 4.8 Total 7.87

The resin used is a strongly acidic cation exchanger, sulfonated polystyrene, cross-linked with bridges of 3.5% divinylbenzene, the resin being used as. The average size of the resin layer is 0.32 mm. Separation is carried out at 55 ° C. A column with a height of 3.5 m and a diameter of 0.225 m is used. The resin is immersed in water. The polyol solution is fed uniformly through the column at a flow rate of 11 l / h and the total amount of solids fed to the column is 2.62 kg as a solution with a solids concentration of 25%. Thus, three portions are served. The xylitol-enriched fractions thus obtained are heated to evaporate 50.8 kg of water, and 2.65 kg of xylitol crystallize from the concentrated solution upon cooling.

The xylitol fraction passing crystallization is as follows

0

five

0

0

five

0

five

stratification of chips at 140 ° C under a pressure of 3.7 at. The solution is purified and hydrogenated as in Example 1. A demineralized solution is obtained containing 10 kg d.c. and having a concentration of 50 wt.%. Hydrogenated solution contains 76.5% xylitol based on rv, and the rest is other polyhydric alcohols (Table 1).

To this hydrogenated solution, the xylitol-enriched fraction obtained from the previous batch is added, and the combined solution of polyatomic alcohols is sent to crystallization. The solution is embedded and two successive crystallization steps are carried out, in which 7.0 kg of crystalline xylitol is extracted. The crystals are separated by centrifugation; the purity of the xylitol contained in them is more than 99.8% (gas chromatography). In total, 175 kg of water was removed from the mixture during the evaporation / crystallization step. In the mother liquor, separated from the crystal, remains 15.5 kg dm, which contains 55.0% of xylene (Table 1). This separated mother liquor is subjected to chromatographic separation as in Example 1. The separation conditions are as follows.

The diameter of the column cm 22,5

Column height, m 3.5 ResinSulfonated polystyrene containing 3.5% DVB

The average size of the spheres, mm TeNmepaTypa, C Consumption, l / h Concentration of the initial solution

Amount of feedstock

0.24

55

15

25 g / 100 g of solution

3.1 kg r.v.

measures

Mass, kg.v.,%

4,8284,4 50

0.396.8

0.111.9

0.071.2

0.173.0

0,152,7 55 5,71 2. The hydrolyzate is prepared from birch chips by ex Separation requires five consecutive loads. The xylitol-enriched fractions obtained from these loads are combined and a fraction enriched in xylitol containing 12.5 kg dv, in which xylitol accounts for 62.9%, is obtained,

Example 3. Separation of a mixture of polyatomic Spirton, and the concentration of xylitol in the mixture does not exceed

50% r.d.

The raw material - birch chips - is hydrolyzed by the method of example 1. The hydrolytic acid is purified and treated with ion exchange resin according to the method of example 1. Sugars are not separated by chromatography, but the purified mixture of HYDR1FUH sugars is as described in Example 1. After hydrogenation, demineralization is performed as in Example 1.

Xylitol crystallizes from the solution. The composition of the uterine paciBopa, which follows from crystallization,

The hydrolysis of birch chips, pre-purification, chromatographic separation of sugars, hydrogenation and demineralization are carried out according to the method of example 1,

The composition of the demineralized mixture of polyhydric alcohols next

Substance With, in.,%

Xylitol79,3

Arabinite1, 3

Sorbitol22.2

Mampit7, 1

Ramnit4,2

Other5,5

This mixture of polyhydric alcohols is divided chromatographically according to the method of Example 1. The following conditions are used: the supplied amount is 3.8 kg d.v., concentration 29 mlc.%, Column m ((and O, 225 m), nozzle size 0, 23 mm, temperature 46 ° C, flow rate at the feed of 0.25 m / m h, the resin in the column is in the A1-form.

Fraction is extracted from the eluent, co, returning the output of the fraction of fractions is 35 minutes with

0

five

2.7 15.5 0.3 0.9

the method has the following number of 3 kg r.v., concentration 35 wt.%, column 3.5 mm (0 0.225 m), nozzle size 0.36 mm, flow rate at a supply of 0, 0.38 m / m-h, resin in the column is in A1 - (1) 0рме, temperature 51 ° С

Three fractions were isolated from the eluent: containing the desired product, returnable and a mixture of polyhydric alcohols. Fraction boundaries were observed 57 and 99.6 minutes after the start of separation.

Xylitol is crystallized from the solution of the product according to the method of Example 1. The return fraction was returned to the process, and the mixture of polyhydric alcohols was isolated as a residue.

Example 5. The separation of sugar alcohols by chromatographic fractionation on a column with ion exchange resin. The resin used is a cation-exchange resin of a strongly acidic nature, namely, a sulfonated polystyrene resin, cross-linked; with 3.5% divinylbeneol, and the resin is used in a strontium form. The average particle size of the resin is 0.32 mm. The separation is carried out at. The column has a height of 350 cm and a diameter of 22.5 cm. The column with the resin is immersed in water. The solution of polyhydric alcohols is fed from the column at a constant rate of 15 l / h, and the total amount of solids supplied to the column is 4 kg (as a solution with a solids concentration of 28%). The solution of polyatomic alcohols, as determined by gas chromatography analysis, has the following composition,%

Arabinite

Xylitol

Mannitol

Galactite

Sorbitol

Substance of unknown structure 6

A useful fraction enriched in xylitol is obtained by combining fractions from 31 to 57. As a result, an AO l solution of the following composition is obtained,%

Arabinite27

Xylitol 1792 (90%)

Mannitol 12

Galaktit28

Sorbitol140

Example 6. Separation of unhydrogenated sugars and polyatomic alcohols from a solution of hydrogenated pentose by chromatographic separation on a column with an ion exchange material whose height is 1 m, and a diameter of 1 O cm. sulfonated polystyrene resin, crosslinked with 3.5% di-vinyl benzene, the resin being in calcium form. Average time10 66 8

5 5

0

five

0

five

five

0

five

0

five

0

The particle gauge is 0.25 mm. Spreading was carried out at 50 ° C with a feed rate of 0.30 l / h. The initial load contains a hydrogenated mixture containing 57 g of solids in the form of a 28% aqueous solution. Solids have the following composition,% Xylitol77.0

Arabinite3,5

Mannit7.0

Galaktit3,5

Sorbitol3,5

Impurities of unknown structure 3.0

Xylose2.0

Several fractions are collected and analyzed using gas chromatography. The results are shown in Table. 2

When the fractions from 6 to 13 are combined, a solution of polyatomic alcohols is obtained, which almost does not contain non-identifiable impurities of non-hydrogenated sugars.

Example 7. Separation of hexite and pentites with the use of a synthetic mixture of sorbitol and xylitol, as well as with the use of sulfonated polystyrene cation exchange resin, crosslinked with 3.5% divinylbenzene. Several resins have been evaluated, including the resins in the following cationic form:

  can t

A1, C Of these cations, cations give the best results. and The results of the experiments are given in table. 3

The following values are calculated: K - distribution coefficient, NETP - value for xylitol (height of the theoretical terrate), Rg dissolution.

The distribution coefficients, the NETP values and the values characterizing the dissolution are calculated. These values are the parameters commonly used to estimate separation in columns and are calculated using the following formulas.

Y- - Y-. „,

h

Cl

NETR - 16 P 2fVea-Veil

   mt

X

Sh.

m

m + m,

where cd is the distribution coefficient; NETR - the height of the theoretical plate;

R - dissolution; Vf is the elution volume for the peak; YO is the apparent volume of the column; Vi is the total volume of the column; h is the height of the column; N is the number of theoretical -1x plates; M is the band width of eluted

peak determined on the to axis of the volume (or time) per unit volume (.ig; and time).

15

25

When studying this table, it is obvious that sorbitol elutes before x1-1lite and that the best separation occurs when using Fe cations and

In this example, the following conditions for the separation of sorbitol and xylitol are used: the height of the column is 84 cm, the bottom is 20 meters — 4.4 cm; temperature feed rate of 3.2 ml / min; polystyrene-sulphonate resin, crosslinked with 3-4% divine benzene, average particle size 0.18 mm, in the form of loading - a synthetic mixture of sorbitol and xylitol f1: P; total amount - 25 g r.v., concentration 35% by weight.

Example B. The separation of each of the five polyhydric alcohols, which are hydrogenated wood hydrolyzates, on the cation exchange resin described in Example 7, in the form. The conditions for the separation of polyhydric alcohols are as follows: a column height of 84 cm, diameter - 4.4 cm; temperature feed rate of 3.2 ml / min; polystyrene sulphonate resin with a content of 3-4% TWO,

thirty

35

139149410

temperature feed rate download 3.2 ml / min; resin (example 7) in the form; load - a solution of polyhydric alcohols, the total amount of 23.5 g rv, concentration 34.9 (the composition is given in example 8). The results are summarized in table. four.

The distribution of polyatomic alcohol with a combination of fractions: a) 1-6 / 7-12 or b) 1-7 / 8-12 is given in table. five.:

Example 10. A double fractionation technique to obtain xylitol by the proposed method.

In the first stage of the process, the hydriro-BaHHbDi wood hydrolyzate is fractionated on a resin in the form of an alkali earth metal and three fractions are collected from the effluent stream, namely the fraction enriched in xylitol, the polyhydric alcohol fraction and fraction i of the waste. Xylitol is crystallized from the coat; xylitol-enriched mi and xl-stitched crystals are isolated from centrifugal broth syrup. Uterine syrup remaining after centrifugal -} - ni is combined with the polyatomic alcohol fraction obtained after the first one. fractionated solution, and the resulting mixture of solution 11 of polyhydric Alcohols is then subjected to the second fractional

Dr. J. “I. 4-4 on the resin in AL - or in re - form,

After the second fractionation, the effluent stream again collects i three fractions, and in one place the fraction enriched in xylitol, the polyatomic alcohol fraction and the waste fraction. After the second fractionation, the fraction enriched in xylitol is combined with the fraction enriched in xylitol, after the first fractionation and their combined solution, the xylitol is extracted by concentration and crystallization. The polyhydric alcohol fraction after I of the second fractionation is added to the next loading of the solution fed to the first fractionation, and the combined solution is fractionated on a resin column in the form of an alkaline earth metal, as discussed for the first fractionation.

average particle size of 0.18 mm in shape; loading solution of polyatomic SP1FTs, total amount - 25 g rv, concentration 35%.

The stock solution (23.5 g c.v., concentration 35 g per 100 ml) has the following composition,%

Mannit8,9

Arabinite9.1

Galaktit5,1

Xylitol 64,0

Sorbitol12.9

Example 9. The separation of 5 polyhydric alcohols present in the hydrogenated products of wood hydrolysis, on the cation exchange resin, discussed in example 7, using the α-form. The conditions for the separation of polyhydric alcohols are as follows: column heights are 82 cm, diameter — 4.4 cm;

five

0

0

five

0

five

five

0

; xylitol-enriched mi and xl-stitched crystals are isolated from centrifugal broth syrup. Uterine syrup remaining after centrifugal -} - ni is combined with the polyatomic alcohol fraction obtained after the first one. fractionated solution, and the resulting mixture of solution 11 of polyhydric Alcohols is then subjected to the second fractional

Dr. J. “I. 4-4 on the resin in AL - or in re - form,

After the second fractionation, the effluent stream again collects i three fractions, and in one place the fraction enriched in xylitol, the polyatomic alcohol fraction and the waste fraction. After the second fractionation, the fraction enriched in xylitol is combined with the fraction enriched in xylitol, after the first fractionation and their combined solution, the xylitol is extracted by concentration and crystallization. The polyhydric alcohol fraction after I of the second fractionation is added to the next loading of the solution fed to the first fractionation, and the combined solution is fractionated on a resin column in the form of an alkaline earth metal, as discussed for the first fractionation.

TaKiiM thus, an antiderivative method allows to obtain crystalline xylitol with a yield of 85-90% compared with a yield of 50-55% according to the known method 1, with a sufficiently high degree of purification.

Claims (1)

Invention Formula The method of obtaining xylitol by acid hydrolysis of xylose-containing material, removing suspended solids from the reaction mixture by filtration, evaporating the obtained filtrate, removing from the evaporated solution of inorganic salts and coloring substances with a strongly acidic cation exchanger, and then weakly basic anion exchangers, evaporating the resulting solution, removing the residual content of the colorant using an ion exchanger or activated carbon, passing the resulting discolored solution through a column x Otography, filled with sulfated polystyrene-divinylbenzene ion exchange resin containing strontium or calcium ions, in the form of a 26–2%% aqueous solution at a rate of 0.21–0.38 using water as elgoent to obtain a fraction containing pentose and a small amount of xypos excreted from the system and the xypose enriched fraction, hydrogenation of the resulting fraction enriched in xylose in the presence of nickel as a catalyst Rene removing from the reaction mixture Hydrogenated solution Xylitol-rich fraction The solution of polyhydric alcohols (mixture l-t-Z) Uterine Liquid Liquid Waste Xylitol Crystals - 0 catalyst filtration, purification of the obtained solution successively with the help of a resin forming a chelate complex, strongly acidic cationioite, aniopite, and passing the resulting O purified solution through a column filled with sulfonated polystyrene-divinite-benzene cation-exchange resin containing metal ions at 46-55 ° C to obtain a fraction containing unhydrogenated sugars that are removed from the system, fractions enriched with xylitol, and fractions containing impurity polyodes and a small amount of xylitol that is removed from the system , crystallization of xylitol from the fraction enriched by it, and returning the resulting mother solution to the chromatographic separation of hydrogenation, characterized in that, in order to increase the yield of the desired product, the process of chromatographic separation of the hydrogenated is carried out using a resin containing ions of aluminum or iron in a column 3.5–5.5 m long, through which 25–35% aqueous solutions of separable substances with a skorustyash 0.25–0.36 m / m – h are passed using as eluent water. Table 1 5.2 4.3 7.1 2.4 4.6 5.9 5.3 7.7 15.3 4.8 13.0 9.4 13.7 15.8 0.55 0.65 0.2 0.75 0.65 0.15 4, 9, 65, 15 0.3 1.2 0.6 0.05 0.6 1.1 0.3 0.05 1.8 4.45 8.15 9.0 8.1 6.5 4.65 1.55 0.1 0.6 0.5 0.4 0.3 0.15 Table 3 17 139149А18 Table 5 82 A2 76 8 77 92 62 89 38 88 eight 38 1 I 62 12