CN104611476B - Method for separating xylose and arabinose - Google Patents

Abstract

The invention relates to a method for separating xylose and arabinose by using ion exchange fibers as chromatographic fillers, using ion exchange fibers as chromatographic separation fillers for the separation and preparation of high-purity xylose and arabinose from xylose crystallization mother liquor; The ion-exchange fiber is a strongly acidic ion-exchange fiber with a diameter of 8-170 μm in a dry state and a cation exchange capacity of 2.0-4.3 mmol/g. Before being used for the separation of xylose crystallization mother liquor, calcium ions need to be replaced in advance , to complete the conversion from the hydrogen form to the calcium form. Compared with ion-exchange granular resin columns, strongly acidic ion-exchange fibers exhibit better separation precision and higher production efficiency.

Description

A method for separating xylose and arabinose

technical field

The invention relates to a process for separating and preparing high-purity xylose and arabinose from xylose crystallization mother liquor by using strongly acidic ion exchange fiber as a new chromatographic filler, belonging to the technical field of chromatographic separation.

Background technique

At present, the domestic xylose production process is to obtain xylose liquid from corn cob or bagasse under the condition of acid hydrolysis. During the xylose crystallization process, due to the high miscellaneous sugar content, a large amount of xylose in the crystallization mother liquor is difficult to crystallize, and the final xylose Most of the crystallization mother liquor is used as low-cost processing of pigment raw materials, and its utilization value is very low. Since the physical and chemical properties of several monosaccharides in the xylose crystallization mother liquor are very similar, it is difficult to separate and purify them. At present, the common separation and purification methods of monosaccharides mainly include: chemical method, membrane separation method, biological fermentation method and chromatographic separation method. Chemical methods can effectively separate xylose and arabinose, but due to the need to derivatize monosaccharides, the process is cumbersome, and a large amount of organic solvents need to be added to the mother liquor, so it is not suitable for the production of food-grade sugars. The membrane separation method uses the selective permeability of the membrane to separate monosaccharides, and is suitable for sugar liquid systems with large molecular weight differences. In the mother liquor of xylose crystallization, glucose and galactose are aldohexose, xylose and arabinose are aldohexose, and the molecular weight difference is not large. Therefore, although membrane separation has a certain enrichment effect on five-carbon sugar, it is difficult to achieve complete Separation still needs further separation of the permeate. Microbial method is the current development direction of green chemistry, but the high price of microorganisms and enzymes has always been an important factor restricting the promotion of this method. At present, in the industrial production of pharmaceutical and food-grade sugars, chromatographic separation technology is used to separate xylose from xylose crystallization mother liquor. The special chromatographic fillers used are mainly imported from Europe, the United States and Japan.

Due to the limited specific surface area and adsorption capacity of spherical particle resin, chromatographic columns in industrial production generally have disadvantages such as large loading capacity, small loading capacity, long adsorption and elution cycle, and high requirements for column length-to-diameter ratio, which lead to production equipment such as Simulating a moving bed is inefficient and complicated. On the other hand, compared with spherical particle ion exchange resins, many advantages of debonding fibers have been widely recognized by scientific research and technical personnel, including large specific surface area, large adsorption capacity, fast exchange and elution speed, easy regeneration, column packing The uniformity of the rear bed and the distribution of the flow field are better and so on. But so far, there are no published literature and patent reports on the technical application of using ion exchange fibers as chromatographic fillers for the separation of xylose and arabinose.

Contents of the invention

The object of the present invention is to provide a novel chromatographic separation method for producing xylose and arabinose, especially a method for separating and preparing high-purity xylose and arabinose from xylose crystallization mother liquor by using ion exchange fiber as a chromatographic separation filler.

The ion exchange fiber used for the separation of xylose crystallization mother liquor is strongly acidic, the exchange capacity is 2.0-4.3 mmol/g, and the diameter of the fiber is 8-170 μm in a dry state.

The ion exchange fibers as fillers can be in the form of short fibers with a length of 5-100 mm, or can be preformed into non-woven fabrics or felts with a bulk density of 100-500 g/mL.

The ion-exchange fiber is used as a filler, and before it is used for the separation of xylose crystallization mother liquor, it needs to be replaced with calcium ions in advance to complete the conversion from hydrogen form to calcium form.

The xylose crystallization mother liquor separation method that adopts ion-exchange fiber provided by the invention as chromatographic filler is characterized in that the implementation process includes the following main steps:

a) Packing of ion-exchange fiber column: The above-mentioned short fiber or non-woven fiber that has been converted into calcium type is completely infiltrated with pure water, and then packed in the column length compression method. The packing density is 200-600g/L, and the packing diameter-to-height ratio is 1:5-70.

b) Loading adsorption: The xylose crystallization mother liquor is injected into the chromatogram filled with water at a constant speed from the column inlet at a constant rate of 0.35-2.5BV/h at a constant separation temperature at a volume of 2.2-8% of the filler volume. column.

c) Elution: After stopping the injection of the sugar solution, immediately use the water in the feed mouth of the column as the mobile phase, and elute the filler according to the water volume of 0.5 to 1.3 times the volume of the filler, and the flow rate of 0.35 to 3.5BV/h to obtain xylose-rich liquid and arabinose-rich liquid.

d) The above steps a)~c) are one load elution cycle, calculated according to the area method in one cycle, when the purity of arabinose is 61% as the cut point, the recovery rate of arabinose is 70-85%, rich in The purity of xylose in the xylose liquid is 86-95%, and the recovery rate is 85-92%.

The above-mentioned steps a) to c) provided by the present invention can be operated continuously in the manner of multi-column series-parallel connection, or in the manner of simulated moving bed.

Preferably, the packing density in step a) is 250-550 g/L.

Preferably, the separation temperature in step b) is 35-60°C.

Preferably, the elution rate in step c) is 0.5-1.5 BV/h.

Beneficial effects of the present invention: Compared with the separation resin method, the separation fiber method is proposed for the first time, which can greatly improve the production efficiency of sugar separation, and under the same processing load, it can reduce the packing volume of the chromatographic bed and reduce the equipment cost; Under the same bed size and process conditions, the processing capacity can be increased, and the product purity is better. In particular, the process conditions defined by the present invention are wider, the service life is obviously prolonged, and the effect is better.

Detailed ways

The following examples are not intended to limit the scope of claims of the present invention, but to further describe the present invention.

Example 1

1) Ion exchange fiber preparation: select strongly acidic ion exchange fibers with a diameter of 33-40 μm and an exchange capacity of 3.3 mmol/g in a dry state, cut them into short fibers of about 3-10 mm, and soak them in pure water. Excess calcium ions are used to replace it to complete the conversion from hydrogen form to calcium form. In particular, the polystyrene-based functional fiber base material proposed in Chinese patent 201310533240.3 is used to prepare ion exchange fibers through cross-linking reaction and functional modification. Other fiber materials that achieve this function are also acceptable. The processing process can refer to the prior art, typical reference materials such as: F. andJ. Homogeneous and Heterogeneous Sulfonation of Polymers: AReview. Polym. Eng. Sci. 1998, 38(5), 783-792.

2) Packing of ion exchange fibers: Soak the ion exchange fibers that have been converted into calcium form in pure water, and pack them in the column length compression method. The packing density of the fibers is 500g/L, and the packing diameter-to-height ratio is 1:70.

3) Separation of xylose mother liquor: 60°Bx xylose mother liquor, in which the concentrations of xylose and arabinose are 31.1% and 14.1%, respectively. Take the sugar solution with 2.2% volume of the filler, and pass it through the ion exchange fiber column at 26°C at a flow rate of 1BV/h for adsorption, and then elute with water 17 times the volume of the sugar solution. The eluted samples were collected after the sugar solution flowed out, and the composition of the eluate was analyzed by HPLC. The xylose-rich liquid and the arabinose-rich liquid were obtained with a separation degree of 0.76. When the arabinose purity of 61% was taken as the cut point, the recovery rate of arabinose was 76%, and the xylose-rich liquid in the xylose-rich liquid had a purity of 93%. %, the recovery rate is 86%.

4) Comparison with spherical particle resin: replace the fibrous filler in the chromatographic column with the same volume of calcium-type granular resin, the average diameter of the resin is about 300 μm, the exchange capacity is 1.5mol/L, and the column is wet-packed after soaking in pure water. The packing density of the resin is 790g/L, and the packing diameter-to-height ratio is 1:70. Under the condition that all parameters are exactly the same as that of the loaded ion-exchange fiber, the amount of eluted water is 23 times the volume of the sugar solution, and the composition of the eluate is analyzed by HPLC. Obtain xylose-rich liquid and arabinose-rich liquid, the degree of separation is 0.49, when taking 61% of arabinose purity as the cut point, the recovery rate of arabinose is 46%, the purity of xylose is 81%, the recovery of xylose The rate is 88%.

Example 2

1) Preparation of ion-exchange fibers: select strongly acidic ion-exchange fibers with a diameter of 33-40 μm and an exchange capacity of 3.3 mmol/g in a dry state, cut them into short fibers of about 3-10 mm, and soak them in pure water. Excess calcium ions are used to replace it to complete the conversion from hydrogen form to calcium form. The ion exchange fiber material of Example 1 was used.

2) Packing of ion exchange fibers: Soak the ion exchange fibers that have been converted into calcium form in pure water, and pack them in the column length compression method. The packing density of the fibers is 500g/L, and the packing diameter-to-height ratio is 1:70.

3) Separation of xylose mother liquor: 60°Bx xylose mother liquor, in which the concentrations of xylose and arabinose are 31.1% and 14.1%, respectively. Take the sugar solution with 3.5% volume of the filler, pass through the ion exchange fiber column at 26°C at a flow rate of 1BV/h for adsorption, and then elute with 12.5 times the volume of the sugar solution with water. The eluted samples were collected after the sugar solution flowed out, and the composition of the eluate was analyzed by HPLC. The degree of separation of xylose and arabinose obtained is 0.67. When the purity of arabinose is 61% as the cut-off point, the recovery rate of arabinose is 72%. The purity of xylose in the xylose-rich liquid is 87%, and the recovery rate is 80%. .

4) Comparison with spherical particle resin: replace the fibrous filler in the chromatographic column with the same volume of calcium-type granular resin, the average diameter of the resin is about 300 μm, the exchange capacity is 1.5mol/L, and the column is wet-packed after soaking in pure water. The packing density of the resin is 790g/L, and the packing diameter-to-height ratio is 1:70. Under the condition that all parameters are exactly the same as that of the loaded ion exchange fiber, the amount of eluted water is 15 times of the volume of the sugar solution, and the composition of the eluate is analyzed by HPLC. Obtain xylose-rich liquid and arabinose-rich liquid, the separation degree is 0.52, when taking 61% of arabinose purity as the cut point, the recovery rate of arabinose is 43%, the purity of xylose is 79%, the recovery of xylose The rate is 89%.

5) Through the comparative analysis of the results, in order to obtain the same separation effect, the granular resin filler used in the chromatographic separation of xylose crystallization mother liquor requires a larger aspect ratio and slower elution speed. It can be seen that using ion exchange fibers as chromatographic fillers can obtain higher separation accuracy in the separation of xylose crystallization mother liquor, and the separation efficiency under the same conditions is much higher than that of granular resin fillers.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those skilled in the art of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (2)

1. ion-exchange fibre is used for xylose method separated with arabinose as chromatograph packing material, it is characterized in that being handed over using ion Fiber is changed as chromatographic isolation filler, for the method that separation prepares high-purity xylose and arabinose in xylose crystallization mother liquor； The ion-exchange fibre is strong acidic ion-exchange fiber, a diameter of 8 ~ 170 μm under drying regime, cation exchange capacity For 2.0 ~ 4.3 mmol/g, it is necessary to carry out the displacement of calcium ion in advance before being separated for xylose crystallization mother liquor, complete from hydrogen Conversion of the type to calcium type；

Use length to be loaded for the short fine form of 5 ~ 100 mm, or use and be pre-formed as bulk density in 100 ~ 500 g/L Non-woven fabrics or felt form, then loaded；

Step is as follows：

a）Ion-exchange fibre column loads：By described short fine or non-woven fabrics form ion-exchange fiber, with pure water complete wetting Afterwards using column length compress mode dress column；Loading density is 200 ~ 600 g/L, and filling blade diameter length ratio is 1:5~70；

b）Material containing is adsorbed：By above-mentioned 25 ~ 60 °C of xylose crystallization mother liquor with 2.2 ~ 8 % volumes of packing volume, by 0.35 ~ 2.5 BV/h flow velocitys, inject water-filled chromatographic column from cylinder feed inlet constant speed；

c）Elution：After stopping injection liquid glucose, mobile phase is done with water in cylinder feed inlet immediately, according to the 0.5 ~ 1.3 of packing volume Times water, 1 ~ 2BV/h flow velocitys elute filler, obtain rich in Xylose and rich in Arabic liquid glucose；

d）Above-mentioned steps a) ~ c) it is that a material containing elutes the cycle, calculated in one cycle according to area-method, take Arab When sugared purity 61% is as cut-point, the rate of recovery of arabinose is 70 ~ 85 %, and the purity rich in xylose in Xylose is 86 ~ 95 %, the rate of recovery are 85 ~ 92 %；

Step a) ~ c) continuously run by the way of multicolumn connection in series-parallel combination or continuously run using Simulation moving bed mode.

2. ion-exchange fibre as claimed in claim 1 is used for xylose method separated with arabinose as chromatograph packing material, It is characterized in that the loading density in step a) is 250 ~ 550 g/L.