JPH072658B2 - Method for producing sugar alcohol stable to heat and / or alkali - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a sugar alcohol stable to heat and / or alkali, and more specifically, to a surfactant, polyurethane, alkyd resin, etc. which are less colored. Stable against heat and / or alkali that can be used as a synthetic raw material,
That is, the present invention relates to a method for producing any one type of sugar alcohol selected from the group consisting of maltitol, which is less likely to be colored by heat and / or alkali, and which has less unreduced sugar, partially hydrolyzed starch, and lactitol.

(Conventional technology and problems) Sugar alcohol is a general term for polyhydric alcohols obtained by reducing (hydrogenating) sugars. Among them, sorbitol is a typical sugar alcohol, and is used as a food, a pharmaceutical raw material, and a synthetic raw material. Widely used. Further, maltitol and a partially hydrolyzed product of reduced starch are being developed for the same use as sorbitol. Further, lactitol, which is a reduced product of lactose, can be expected to be used as a special drug raw material in addition to the food field. Among these applications, sugar alcohol fatty acid ester obtained by reacting sugar alcohol with fatty acid is a hydrophilic nonionic surfactant, which has excellent surface activity and high stability. Compared with fatty acid ester, it is characterized by being relatively stable against heat and alkali.

However, since this esterification reaction is generally carried out at a high temperature under an alkali catalyst, the reaction product is easily colored, and the decoloring operation is usually difficult. For this reason, today, which is directed to high quality and high performance, it is required that the sugar alcohol which is the raw material also be less colored even under the reaction conditions where heat and / or alkali is present.

Further, sugar alcohols have a plurality of functional groups and are more stable to heat and / or alkali than sugars, so they are also used as raw materials for polyurethane, alkyd resins, etc. It is desired to improve the stability of sugar alcohols against heat and / or alkali for production.

However, there is nothing to see in the art for producing such sugar alcohol stable to heat and / or alkali. In the laboratory, maltose that has been repeatedly purified is used as a raw material to reduce impurities derived from the raw material and produce sugar alcohol stable to heat and / or alkali. Have been attempted, and the sugar alcohol after reduction is thoroughly purified to remove substances that are considered to be the cause of coloring as much as possible.
Alternatively, the stability to alkali has not reached the level required at the time of manufacturing a surfactant, a resin or the like.

As mentioned above, all sugar alcohols obtained by these techniques can only slightly reduce the coloration by heat and / or alkali, and the surfactants and resins which require less coloration. A sugar alcohol that is stable to heat and / or alkali that can be used as a raw material of the above has not been produced.

Explaining the prior art in detail, the cause of low stability of sugar alcohol against heat and / or alkali is
It was said to be an unreduced sugar present as an impurity in sugar alcohol. Therefore, it has been considered that the improvement of the stability of sugar alcohol against heat and / or alkali can be achieved by reducing the amount of unreduced sugar. However,
It has been difficult to reduce the unreduced sugar to a solid content of 0.05% or less by a general industrial method of reducing sugars, that is, a method of carrying out catalytic hydrogenation at high temperature and high pressure under a reducing catalyst such as Raney nickel. As a simple solution, if a large amount of catalyst is used and the reduction reaction is carried out at a higher temperature than usual for a long time, unreduced sugar may sometimes be less than 0.05%, but in that case, the catalyst cost is not negligible. In addition, it was necessary to pay attention to the decomposition and isomerization reactions of sugar and suppress the formation of impurities. Further, a method of reducing the obtained sugar alcohol again to reduce the unreduced sugar was also considered, but the cost is high, and the reduction of the unreduced sugar is not obtained as expected, and those There has been a limit in improving the stability of sugar alcohols against heat and / or alkali in the prior art.

(Means for Solving Problems) The present inventors have deeply studied the method for improving the stability of sugar alcohol, and as a result, as described above, even if the amount of unreduced sugar is minimized, the heat and / or heat of sugar alcohol is reduced. Alternatively, it has been found that the stability to alkali, and thus the coloring of a product such as a surfactant obtained by using this sugar alcohol as a raw material, cannot be reduced to a certain level or less. This is because not only the unreduced sugar is the cause of coloration but also the starch, which is the raw material of the sugar,
Or, it can be considered that it is also present in trace components derived from saccharifying enzymes, and it has been found from the results of repeated purification experiments that these substances cannot be completely removed by conventional purification means such as activated carbon or ion exchange. .

An object of the present invention is to industrially provide a sugar alcohol stable to heat and / or alkali that can be used as a raw material for synthesis by removing these coloring-causing substances at low cost.

The present inventors have conducted extensive studies to solve the above problems, and as a result, any one sugar selected from the group consisting of maltitol, a partially hydrolyzed starch reduced product, and lactitol obtained by an ordinary method. By a simple means of adding an alkali to an aqueous alcohol solution and performing heat treatment, it reduces unreduced sugar, which is considered to be the largest cause of coloring, and also causes coloring of unknown structure, which is considered to be derived from raw sugar or enzyme. The present invention has been completed by altering a trace amount of substances present therein, and further removing the altered substance by ordinary purifying means such as activated carbon or ion exchange.

Maltitol can be obtained by reducing maltose. The maltitol described here contains sorbitol, maltotriitol, and other sugar alcohols in addition to those containing maltitol as a main component. in this case,
The maltitol content (relative to solid content) is preferably 75% or more.

The raw material for the partially hydrolyzed starch is a partially hydrolyzed starch, and there are various products depending on the degree of hydrolysis. Utilization of fatty acid ester, resin, etc. obtained by reacting this , It is necessary to select the quality according to the desired properties. However, any kind of raw material may be used for the purposes of the present invention.

Lactitol is a sugar alcohol obtained by reducing lactose. Since it has good crystallinity, lactitol is easy to obtain with high purity, and is highly utilized as an industrial raw material.

These sugar alcohols used in the present invention are generally prepared by forming a 40-75% aqueous solution of sugar into a high-pressure reactor while mixing and stirring with a reducing catalyst, and adjusting the hydrogen pressure in the reactor to 50%.
~ 200 kg / cm ² , adjust the reaction temperature to 70 ~ 180 ℃, carry out the reduction reaction until hydrogen absorption is no longer observed, after the reaction is completed, the catalyst is separated, ion exchange resin treatment, activated carbon treatment if necessary It is obtained by decolorizing and desalting with, for example, and then concentrating to a predetermined concentration. In the present invention, not only the sugar alcohol obtained by the above method, but also the commercially available sugar alcohol can be used as it is to achieve the object.

Next, the alkali heat treatment method for these sugar alcohols according to the present invention will be described. An appropriate concentration, preferably 20 to 60% of a sugar alcohol aqueous solution is added with an alkali such as a hydroxide of a metal such as sodium, potassium or calcium, a carbonate or the like, and the pH is adjusted to 9.5 or more and 13 or less, 110 ° C or more 14
After heating at a temperature of 0 ° C. or lower for 5 minutes to 2 hours, ion exchange resin treatment and, if necessary, activated carbon treatment are carried out by a conventional method, and desalting and decolorization purification are carried out to achieve the purpose.

Even if a sugar alcohol concentration of less than 20% or more than 60% is used, there is no problem in the effect of improving stability against heat and / or alkali, but if the concentration is too low, concentration in a later step If the cost is high and, on the contrary, the concentration is too high, it is not industrial because the resin floats during the treatment in the subsequent ion exchange resin treatment step. 25% added alkali
Although an aqueous solution of a certain degree is preferable, if the pH can be adjusted, a slurry state or solid state alkali may be used.

The heating time is 5 minutes to 2 hours, which needs to be appropriately selected according to pH and temperature. That is, the higher the pH and the higher the temperature, the shorter the heating time. However, pH
Is too high, the ion exchange load for removing the added alkali becomes large, so pH is preferably 13 or less, and when the heating temperature is too high, sugar alcohol decomposes to form a low boiling point substance or , Maltitol, partially hydrolyzed starch, and lactitol may be hydrolyzed, so it is preferable to heat them at a temperature of 140 ° C. or lower.

Any heat treatment device may be used as long as it can maintain a temperature of 110 ° C. or higher, and it is not necessary to select the material. For example, in the laboratory, glass or stainless steel is sufficient as the material for the reaction vessel, and a sugar alcohol solution whose pH is adjusted is put into this and heated on a burner, or if necessary, put in a normal steam sterilization kettle to obtain high pressure. Steam heat treatment at. Industrially, continuous treatment is preferable in terms of thermal efficiency, equipment cost, etc., and mass production becomes easy. Also in this case, it is not necessary to use a special material such as glass lining as the material of the liquid contact part, and stainless steel is sufficient.

Furthermore, to explain the subsequent purification treatment, the heat-treated sugar alcohol liquid is cooled to a temperature at which there is no danger in work (generally 70 ° C or less) and treated with activated carbon or with an ion-exchange resin treatment without decarbonization to decolorize. Desalt. When the activated carbon is treated, it is preferable to use 0.1 to 5% of activated carbon based on the sugar alcohol solid content. In the ion exchange resin treatment, the sugar alcohol liquid is passed through a cation resin tower, an anion resin tower, and a mixed bed tower in this order. The manufacturer, type and product number of the ion exchange resin to be used are not particularly limited, but a strong acid cation exchange resin for the cation resin and a weakly basic anion exchange resin for the anion resin give good results. It is better to select an anion exchange resin with a high decolorizing property for better workability. The sugar alcohol solution after the ion-exchange purification is concentrated if necessary and provided for various purposes.

(Examples) The following examples are given to describe the present invention in more detail.

Example 1 (% of solid content) Maltitol 82.3 Sorbitol 5.2 Maltotriitol 8.2 Other sugar alcohol 4.3 1 kg of 40% aqueous solution of sugar alcohol (C) having the above composition was adjusted to pH 12 with sodium hydroxide, and 120 ° C. for 30 minutes Heated.
After cooling, 200 ml of cation exchange resin SK-1B,
Anion exchange resin WA-30 (both manufactured by Mitsubishi Kasei Co., Ltd.)
Further, it was passed through a mixed bed resin (a mixture of SK-1B and WA-30 at a ratio of 1: 2) for purification, and concentrated to a 50% liquid.

The concentrated liquid (344 g) was evaporated under reduced pressure to remove water, and 128 g of palmitic acid and 3 g of sodium carbonate were added to the concentrated liquid (220 g) in a nitrogen stream.
The reaction product (D) was obtained by heating at 100 ° C. for 100 minutes. Acid value
It was 9.3.

For comparison with the case where the esterification reaction was carried out without alkali treatment, sugar alcohol (C) 430 and 128 g of palmitic acid were esterified by the above method to obtain a reaction product (E). The acid value was 8.8.

To compare the degree of coloring, 10 g of the reaction product was dissolved in 100 ml of butanol under heating and filtered. The filtrates were compared in terms of color by the Gardner method (D) was Gardner 1 and (E) was It was 9.

Example 2 100 g of a reduced starch partial hydrolyzate (referred to as F; trade name PO-40, manufactured by Towa Kasei Kogyo Co., Ltd.) containing 0.4% unreduced sugar was made into an aqueous solution having a concentration of 40% and 25% potassium hydroxide. Aqueous solution was added to adjust pH to 11. This was placed in an Erlenmeyer flask and treated in the same manner as in Example 1 except that the heating temperature and the time were 135 ° C. for 1 hour to obtain a 50% sugar alcohol aqueous solution (referred to as G). This unreduced sugar was 0.03%.

To compare the thermal stability of (F) and (G), each 40g
Was placed in a beaker, the pH was adjusted to 10 with an aqueous sodium hydroxide solution, and dried under reduced pressure at 80 ° C. for 12 hours to give an anhydride. This 16
After heating at 5 ℃ for 3 hours, water was added to make a 50% aqueous solution, and the absorbance was measured at a wavelength of 420 nm and a cell length of 10 nm (F).
The absorbance was 2.59 and (G) was 0.28.

Example 3 150 g of lactose, 125 g of water and 10 g of Raney nickel catalyst,
The mixture was placed in an electromagnetic stirring autoclave having an inner volume of 550 ml, reduced at 130 ° C. for 2 hours while maintaining a hydrogen pressure of 130 kg / cm ² , separated from the catalyst, treated with activated carbon and an ion exchange resin to carry out reduction purification. Concentrate the purified liquid further 75
% Crystallized and dried, lactitol anhydrous 70
g was obtained (denoted as H). This unreduced sugar was 0.05%. Make 35g of this into a 40% aqueous solution and pour with sodium hydroxide.
After adjusting H to 11, the mixture was heated at 130 ° C. for 1 hour and then purified in the same manner as in Example 1 to obtain 60 g of lactitol solution (referred to as I).

(I) was heated to 150 ° C while concentrating under reduced pressure, and when water did not distill, 22.7 g of palmitic acid and 0.7 g of potassium carbonate were added, and the mixture was heated at 230 ° C for 2 hours while stirring in a nitrogen stream to produce a reaction. The thing (J) was obtained. Also, 30 of (H)
g was subjected to an esterification reaction in the same manner as above to obtain a reaction product (K).

To compare the coloring degree of (J) and (K), 10 g of each is 100
When APHA was measured by dissolving it in ml of methyl ethyl ketone, (J) was 20, and (K) was 130.

(Effect of the invention) The sugar alcohol stable to heat and / or alkali of the present invention has a small amount of unreduced sugar, and the coloring-causing substance has also been removed.
By using the sugar alcohol of the present invention as a raw material, it is possible to obtain a surfactant, a resin and the like with little coloring. Furthermore, since the manufacturing method is a simple process of only heat treatment after pH adjustment,
There is no operation mistake and no skill is required. Further, the manufacturing apparatus does not have to be special equipment, and the continuous operation apparatus can be installed at a low price, so that the sugar alcohol of the present invention can be supplied in large quantities at low cost.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaru Hidagi 9-1-204 Hiromi Nishihonmachi, Fuji City, Shizuoka Prefecture (56) References Japanese Patent Publication No. 41-12212 (JP, B1)

Claims (1)

[Claims] 1. Maltitol, a partial hydrolyzate of reduced starch,
And a sugar alcohol aqueous solution selected from the group consisting of lactitol and alkali, adjusted to pH 9.5 to 13 with an alkali, heat-treated at a temperature of 110 ° C to 140 ° C for 5 minutes to 2 hours, and then purified. A method for producing a sugar alcohol stable to heat and / or alkali, which comprises: