JP2712032B2 - Method for producing antifoam for fermentation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a method for producing a polyalkylene glycol-based antifoaming agent for fermentation.

[Prior art]

Examples of conventional polyalkylene glycol-based antifoaming agents for fermentation include diol types such as polypropylene glycol and polyoxyethylene-polyoxypropylene block copolymer, and polyhydric alcohols such as glycerin having an average molecular weight of 20.
As about 00 to 4000, there are many compounds to which an alkylene oxide is added, and as the structure of the alkylene glycol, a homopolymer of propylene oxide, a block copolymer of ethylene oxide-propylene oxide, and a random copolymer are used as antifoaming agents for fermentation. Also known are alkylene oxide adducts of higher alcohols and higher fatty acids. In addition, a number of polyalkylene glycol-based antifoaming agents, including general antifoaming agents, have been filed as patents, and many of them describe the type of alkylene oxide and the position or order in which the alkylene oxide is added. (Special Publication 41
-16528, JP-B-45-30189, JP-B-53-44551, JP-B-58-58125, and JP-A-56-169583)

[Problems to be solved by the invention]

Such a conventional polyalkylene glycol-based antifoaming agent is generally obtained by addition-polymerizing an alkylene oxide to an organic compound containing at least one active hydrogen group in the molecule in the presence of an alkaline catalyst. Examples of the alkaline catalyst used in this reaction include caustic potash, caustic soda, sodium methylate, potassium methylate, metal potassium, potassium carbonate, sodium carbonate and the like. The polyalkylene glycol-based antifoaming agent obtained by these methods contains an alkaline catalyst and by-products, and examples of the by-products include aldehyde compounds, propenyl compounds, and cyclic ethers. When these alkaline catalysts or their neutralized salts and by-products remain in the polyalkylene glycol-based defoaming agent, they are usually removed. As a purification method for removing by-products from a polyalkylene glycol-based antifoaming agent containing an alkaline catalyst or a polyalkylene glycol-based antifoaming agent from which an alkaline catalyst has been removed, there are the following methods. (A) A method in which a polyalkylene glycol-based antifoaming agent containing an alkaline catalyst and a by-product is neutralized with a mineral acid or an organic acid, and then washed with a large amount of water. (B) A method in which a polyalkylene glycol-based antifoaming agent containing an alkaline catalyst and a by-product is treated with an adsorbent such as activated carbon and / or synthetic magnesium silicate. (C) Distillation under reduced pressure while continuously adding water to a polyalkylene glycol-based antifoaming agent containing by-products. The method (a) has high solubility of by-products, that is, aldehydes, has a bad smell, and is not practical at all. This method also has very poor removal of neutralized salts. In the method (b), the removal of by-products, that is, dealdehydes are insufficient, and the yield is poor because a large amount of adsorbent is used. In the method (c), by-products are removed immediately after purification, that is, dealdehydes are high. However, since they are probably physicochemical, they are not complete and considerable propenyl groups remain. For this reason, aldehydes are generated over time. As described above, the polyalkylene glycol-based antifoaming agent produced by the conventional purification method includes a neutralization salt derived from an alkaline catalyst, and an aldehyde compound as a by-product.
Including the propenyl compound and the cyclic ether, especially when the presence of the aldehyde compound as a by-product was used in the fermentation industry as an antifoaming agent, despite its trace amount, it was found that the inhibition on the growth of bacterial cells was large. .

[Means for Solving the Problems]

The present invention has been made in view of such conventional problems. That is, a general formula synthesized in the presence of an alkaline catalyst, (Where A has 2 to 8 hydroxyl groups, glycol, aliphatic polyhydric alcohol, or saccharide residue, R ₁
And R ₂ are the same or different alkylene groups having 2 to 8 carbon atoms, x is a number corresponding to the hydroxyl group of a glycol, an aliphatic polyhydric alcohol or a saccharide residue, l is 0 to 20, and m is 3 to
40, n is 3 to 30, both R ₁ R ₂ are ethylene groups, or _{one of} R ₁ R ₂ is an ethylene group, and the other is a block polymer or a random number of an alkylene group having 3 to 8 carbon atoms. A polyalkylene glycol, which is a polymer and has an oxyethylene chain occupying 5 to 30% by weight of the total molecular weight), in the presence or absence of water, with a dissociation constant (in an aqueous solution at 25 ° C) The first dissociation constant, the same shall apply hereinafter) ^10-3 or more of a mineral acid or an aqueous solution thereof is added to adjust the PH value to 6.5 or less, then an acid adsorbent is added, and dehydration and dealdehydes are heated to a temperature of 50 to 150 ° C, Decompression degree 50m
Perform at a pressure of mHg or less while blowing water, steam or nitrogen gas. To provide a method for producing an antifoaming agent for fermentation comprising, as a main component, a compound obtained by purification by the above method. (Requirements Constituting Means) The glycol, aliphatic polyhydric alcohol or saccharide having 2 to 8 hydroxyl groups used in the present invention includes ethylene glycol, propylene glycol, 1.4 butanediol, glycerin, trimethylolpropane,
Examples include pentaerythritol, sorbitol, sorbitan and one or a mixture of sugars such as glucose, fructose, lactose, sucrose and starch. Examples of the alkylene oxide having 2 to 8 carbon atoms used in the present invention include alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, tetrahydrofuran, and styrene oxide. Mineral acids having a dissociation constant of 10 ⁻³ or more or an aqueous solution thereof used for neutralization include H ₂ SO ₄ , HCl, HNO ₃ , HClO ₂ , NH ₂ SO ₃ H, H ₂ S ₂ O ₃ , H ₂
PO ₂ , H ₄ P ₂ O ₇ , HClO ₃ , HIO ₃ , H ₃ PO ₄ , H ₃ PO ₃ , H ₂ SO ₃ and their aqueous solutions. The polyalkylene glycol used as the antifoaming agent for fermentation according to the present invention is, for example, ethylene oxide at a temperature of 60 to 180 ° C. and a pressure of 0.5 to 5.0 kg / cm ² using glycerin, which is a polyhydric alcohol, as an alkaline catalyst. Addition followed by propylene oxide gives a crude polyalkylene glycol. A mineral acid having a dissociation constant of 10 ^-3 or more, for example, sulfuric acid is added to this crude product, that is, a polyalkylene glycol containing an alkaline catalyst and by-products, to adjust the pH value in the system to 6.5 or less. When the pH value in the system exceeds 6.5, the propenyl group causing the generation of aldehydes does not completely disappear immediately after purification or gradually over time. Therefore, it contains a large amount of aldehydes. Next, demineralizing acid is performed with an acid adsorbent such as synthetic magnesium silicate or synthetic aluminum silicate. If necessary, a crystallization agent such as aluminum phosphate may be added in order to promote the growth of the salt crystals generated at this time. Next, dehydration and dealdehydes are performed. For dehydration and dealdehydes, the temperature is 50-150 ° C, and the degree of decompression is 50mmH
This is performed while blowing water, steam or N ₂ gas at a g or less. If the conditions are not satisfied, removal of by-products, that is, removal of aldehydes caused by complete disappearance of the propenyl group by the mineral acid is not complete, and the desired polyalkylene glycol cannot be obtained. Next, the polyalkylene glycol according to the present invention is obtained by performing filtration by a known method. Next, the present invention will be specifically described with reference to examples.
Example 1 An autoclave was charged with 92 g of glycerin and 8 g of caustic potash as a catalyst, and dehydrated under vacuum at a temperature of 110 to 130 ° C. and 50 mmHg for 2 hours to carry out alcoholation. Next, 660 g of ethylene oxide is introduced at a temperature of 110 to 160 ° C. under a pressure of 1 to 5 kg / cm ² for about 3 hours to cause a reaction. Subsequently, 3480 g of propylene oxide was heated at a temperature of 110 to 160 ° C and a pressure of 1 to 5 kg / cm ^2.
It took about 7 hours to introduce and react under the conditions described above, and cooled to obtain a polyoxyalkylene compound containing an alkaline catalyst and by-products (hereinafter referred to as a crude polyoxyalkylene compound). 75 to this crude polyoxyalkylene compound
10 g of orthophosphoric acid by weight is added and mixed by stirring.
Time processed. The pH value of the system was 5.5. Next, 10 g of synthetic magnesium silicate was added and demineralized at 80 ° C. for 1 hour.
The solution was heated up to 5 ° C., decompressed to 5 mmHg, and dehydrated and dealdehyded for 2 hours while blowing N ₂ gas at a rate of 200 ml / min. Next, the crystals of the salt were filtered with an ultrafilter to obtain a purified polyoxyalkylene compound, which was designated as a polyalkylene glycol-based defoamer sample No. 1 of the present invention. Furthermore,
Purified polyoxyalkylene compounds synthesized and purified in substantially the same manner were designated as polyalkylene glycol-based defoamer samples Nos. 2 to 4 of the present invention. Example 2 An autoclave was charged with 92 g of glycerin and 8 g of caustic potash as a catalyst, and dehydrated under vacuum at a temperature of 110 to 130 ° C. and 50 mmHg for 2 hours to carry out alcoholation. Next, 696 g of propylene oxide is introduced under a condition of a temperature of 110 to 160 ° C. and a pressure of 1 to 5 kg / cm ² for about 3 hours to cause a reaction. Subsequently, a mixed alkylene oxide prepared by mixing 660 g of ethylene oxide and 696 g of propylene oxide in advance is introduced at a temperature of 110 to 160 ° C. and a pressure of 1 to 5 kg / cm ² for about 5 hours to be introduced and reacted. Further, propylene oxide 1740 g at a temperature of 110-
About 7 hours were required under the conditions of 160 ° C. and a pressure of 1 to 5 kg / cm ² , the reaction was carried out by introducing, and the mixture was cooled to obtain a crude polyoxyalkylene compound. 6 g of concentrated sulfuric acid was added to this crude polyoxyalkylene compound, mixed with stirring, and treated at 80 ° C. for 2 hours. The pH value of the system is
2.0. Next, 2.5MgO ・ Al ₂ O ₃・ XH ₂ O (Kyoward
300) Add 5 g, demineralize at 80 ° C for 1 hour, add 5 g of aluminum sulfate, heat to 100 ° C, reduce the pressure to 5 mmHg, and supply N ₂ gas at a rate of 100 ml / min. While blowing, dehydration and dealdehydes were performed for 2 hours. Next, the crystals of the salt were filtered with an ultrafilter to obtain a purified polyoxyalkylene compound, which was designated as a polyalkylene glycol-based antifoaming agent sample No. 5 of the present invention. Furthermore, purified polyoxyalkylene compounds that were synthesized and purified in substantially the same manner were used as polyalkylene glycol-based antifoam samples Nos. 6 and 7 of the present invention. Comparative Example 1 Concentrated sulfuric acid was added to the crude polyoxyalkylene compound of Example 1, mixed with stirring, and treated at 80 ° C. for 2 hours.
The value is 7.0, the neutralized product has a coloring degree of APHA100, and Na ₂ SO ₄
Of fine colloidal crystals are suspended. Then, after cooling, water was added, and the mixture was stirred at room temperature for 1 hour. The separated aqueous layer was separated and removed. The suspended water was reduced to 5 mmHg at 120 ° C. for 3 hours to remove water. Filtration to obtain a purified polyoxyalkylene compound, Comparative Example Sample N
o.8. Further, a purified polyoxyalkylene compound purified by substantially the same method was designated as Comparative Example Sample No. 9. Comparative Example 2 To 3884 g of the crude polyoxyalkylene compound of Example 2, 30 g of synthetic aluminum silicate was added, and 100 g of water was added.
C. and heated for 2 hours. Next, the pressure was reduced to 5 mmHg at 120 ° C. for 2 hours to remove water, and then
Filtration was performed with an ultrafilter to obtain a purified polyoxyalkylene compound, which was designated as Comparative Example Sample No. 10. Further, a purified polyoxyalkylene compound purified by substantially the same method was used as Comparative Example Sample No. 11. Example 3 The polyalkylene glycol-based antifoaming agents obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were placed in 300 g and 500 ml glass sample bottles, respectively, and the aging of the aldehydes was examined. The results are shown in Table 3. The aldehydes were converted to formaldehyde. Example 4 (L-glutamic acid fermentation) L-glutamic acid fermentation medium composition amount (parts by weight) Water was added to the glucose _{2.0 NH 4 Cl 0.7 KH 2 PO} 4 0.1 MgSO 4 · 7H 2 O 0.05 the composition, a whole 100 parts by weight, 0.1
Adjust the pH to 7.0 with N-caustic soda to obtain a culture medium. The above medium was added to a 50 ml shake flask containing 5 μg / l of vithion, and inoculated with a strain of the genus Micrococus.
Incubate for 24 hours with shaking at ℃ to make a preculture. Next, the above medium
50 ml was collected into a 500 ml shake flask, and 0.1% and 0.7% of the polyalkylene glycol-based antifoaming agent shown in Table 1 were added, respectively.
1 ml of the preculture was added, and shaking culture was performed at 30 ° C. for 48 hours. Table 4 shows the amount of L-glutamic acid produced. The polyalkylene glycol-based defoaming agent is 1
One that has been used for a month has been used. The antifoaming agent of the present invention has a higher L-glutamic acid production amount than the comparative sample. This can be said to be extremely low inhibitory to fermentation production. Example 5 The following test was carried out using the same preculture solution and medium as in Example 4. In a 3000 ml fermenter, 50 parts of the medium and 1 part of the preculture were taken and cultured at a flow rate of 2 l / min at a temperature of 30 ° C. for 48 hours. 300 ml of this culture solution was placed in a measuring cylinder and aerated at a rate of 8 l / min for 30 minutes. When the foam generated reached the marked line (1), a polyalkylene glycol-based antifoaming agent was added little by little, followed by 2 hours. Table 5 shows the minimum amount of the antifoaming agent required to suppress the generated foam below the marked line.

【The invention's effect】

The polyalkylene glycol obtained by the production method of the present invention has a very low content of neutralized salts, aldehydes, and propenyl groups that cause the generation of aldehydes. In particular, aldehydes have a bactericidal action against bacteria such as used in disinfectants and preservatives as typified by formalin, and show significant inhibition on the growth of bacteria in fermentation. These problems have been solved by using such a specific manufacturing method.

Claims (1)

(57) [Claims] 1. A compound represented by the general formula, which is synthesized in the presence of an alkaline catalyst: (Where A is a glycol, aliphatic polyhydric alcohol, or saccharide residue having 2 to 8 hydroxyl groups, R1 and R2 are the same or different alkylene groups having 2 to 8 carbon atoms, x is glycol, aliphatic The number corresponding to the hydroxyl group of the polyhydric alcohol or saccharide residue, 1 is 0 to 20, m is 3 to 4
0, n is 3 to 30, both R1R2 are ethylene groups, or one of R1R2 is an ethylene group, and the other is a block polymer or a random polymer having an arbitrary ratio of an alkylene group having 3 to 8 carbon atoms. A polyalkylene glycol represented by the following formula: a dissociation constant in the presence or absence of water (a first dissociation constant in an aqueous solution at 25 ° C.) The same shall apply hereinafter) Mineral acids of 10-3 or more or their aqueous solutions are added to adjust the pH value to 6.5 or less, then an acid adsorbent is added, and dehydration and dealdehydes are heated at a temperature of 50 to 150 ° C and a reduced pressure. 50m
A method for producing an antifoaming agent for fermentation comprising, as a main component, a compound obtained by purification by blowing water, steam or nitrogen gas at mHg or less.