JPS5920653B2 - Manufacturing method of powdered glyoxal - Google Patents

Description

[Detailed description of the invention] Glyoxal has been used in the production of organic chemicals, textile processing,
It is used for various purposes such as paper processing, deodorization, and soil stabilization.

However, when using it, glyoxal is usually commercially available as an aqueous solution with a concentration of about 40%, but powdered glyoxal may be required depending on the application, and if necessary, the powder may be mixed in water. If it is easily converted into an aqueous solution when added to the water, a powder form has the advantage of reducing transportation and storage costs. Conventionally, various proposals have been made as methods for producing such powdered glyoxal.

For example, (1) a method in which seed crystals are added to an aqueous glyoxal solution and left to stand for a long period of time to precipitate white crystals. (2)
A method for obtaining amorphous polyglyoxal hydrate by dehydrating and concentrating an aqueous glyoxal solution. (3) A method in which a powdered inorganic or organic carrier is immersed in an aqueous glyoxal solution and then dried to support glyoxal on the carrier. etc.

However, all of these methods have advantages and disadvantages in terms of production or performance of the obtained glyoxal powder.

That is, in (1), the crystallization rate of glyoxal is very slow. For example, if polyglyoxal seed crystals are added to a 60% glyoxal aqueous solution and kept at 15°C, polyglyoxal crystals of about 50% of the theoretical amount can be obtained. Noni 2
It takes more than 0 days and is hardly an industrially advantageous method. Furthermore, since the crystalline glyoxal obtained by this method has poor solubility in water, there are limitations in its use as an aqueous solution. In (2), as the glyoxal aqueous solution is heated and concentrated, the aqueous solution becomes viscous and eventually becomes a sticky cake-like substance, making it difficult to stir and concentrate using a normal device. The viscous material solidifies when cooled, but it adheres to the container and is difficult to remove and furthermore to crush. (3) is a method for which the present applicant has already filed a patent application and has been put into practical use to some extent, and there are no particular problems in terms of production. However, there is a problem that the carrier remains as an undissolved substance, and even if the carrier is soluble, the dissolution rate tends to be slow, which is a limitation depending on the application. As mentioned above, pulverizing glyoxal itself has various problems and has hardly been put to practical use. The present inventors first conducted research with the aim of finding a practical method for efficiently producing solid, especially powdered, glyoxal, and further, to obtain powdered glyoxal with excellent water solubility. As a result of repeated efforts, they discovered that the above objective could be achieved by applying a shearing force to a viscous substance with a viscosity of 10,000 poise or more at 80°C obtained by heating and concentrating an aqueous glyoxal solution, and filed a patent application. I went.

That is, when concentrating a commercially available 4070 glyoxal aqueous solution by heating and stirring under normal pressure or reduced pressure, when the glyoxal concentration reaches about 6070, it becomes a viscous liquid with a viscosity of about 1 poise. When the viscosity reaches about 70%, the viscosity suddenly increases to over 100 poise, making it more sticky and cake-like than fluid. Even if you try to heat it up and stir it to concentrate and dry it, a normal stirrer won't work. It is extremely difficult to further concentrate and solidify the product using normal methods, as it becomes unusable and causes discoloration and deterioration due to heating unless some kind of stirring is performed.

However, glyoxal concentrated to this level of concentration will solidify if cooled, but like rice cake, it will stick to the wall of the concentrator and it will be difficult to remove the solidified material, and even if it is removed, it will have to be crushed. It's not an easy thing to do. However, when shearing force is applied to the viscous glyoxal that has been concentrated to the extent that it takes on the appearance of a cake-like substance, the cake-like substance gradually loses its adhesive strength and becomes a brittle lump, and when further shearing force is applied, it becomes powdery. It will become. This phenomenon occurs when the glyoxal aqueous solution is concentrated and its viscosity at 80°C decreases to 1.
This occurs when shearing force is applied when the viscosity is 10,000 poise or more, but powdering or embrittlement does not occur when shearing force is applied when the viscosity is 10,000 poise or less. There is no particular restriction on the magnitude of the shearing force, as long as it is at least 103 dynes/Cd, and the greater the shearing force and the longer it is applied, the more remarkable the effect will be. However, the properties of the obtained lumps differ depending on the magnitude of the shearing force and the duration of the shearing force. It turns into small lumps and eventually becomes powder. However, when carrying out such a powdering method industrially, it has become clear that a large-sized device with considerably powerful power is required to apply shearing force.

However, in order to solve this problem, the present inventors conducted further research and found that a viscous substance with a viscosity of 10,000 poise or more at a temperature of 80°C obtained by concentrating an aqueous glyoxal solution is ineffective against glyoxal. When shearing force is applied in the presence of an active organic solvent, the stickiness of glyoxal concentrate is significantly reduced compared to when shearing force is applied in the absence of an organic solvent as described above. , the load on the equipment to apply the same shearing force is reduced, making it possible to powder with a small power equipment, and the ability to powder in a shorter time, which can produce significant practical effects. This discovery led to the completion of the present invention.

The above solvents include hydrocarbons such as n-hexane, n-octane, benzene, toluene, and xylene, esters such as methyl acetate, ethyl acetate, and butyl acetate, ethers such as dioxane and tetrahydrofuran, acetone, methyl ethyl ketone, and methyl Examples include ketones such as isobutyl ketone.

Particularly preferred are solvents with a boiling point in the range of 50 to 150°C. Is the amount of solvent used 2 weight per pure glyoxal?
The effect of the present application can be sufficiently obtained if the degree is 5, but preferably 5
~20 weight? degree is most appropriate.

20 weight? Even after using the above, there is no problem with powdering.
Although it is possible to use such a large amount of solvent, it is not very desirable from an economical or operational efficiency standpoint.

Even if a solvent is added, if the amount falls below the lower limit due to evaporation or the like, it goes without saying that the solvent can be added to adjust the amount within the above range. There is no particular restriction on the timing of addition of the solvent, and it may be added at any time; however, in the present invention, the purpose of using such a solvent is to easily powderize a viscous material like rice cake. It is most advantageous to add the glyoxal aqueous solution just before it becomes concentrated and viscous and begins to become powder, that is, when the load on the device for applying shear force is greatest.

There is no problem in adding the solvent during the concentration process of the aqueous glyoxal solution, but if the solvent is added too far before powderization, the existing water and solvent may cause azeotropy or may not azeotrope. However, there is a risk that the solvent may evaporate due to long-term heating, and there is a problem that there is a shortage of solvent at the time of powdering, and the solvent necessary for powdering must be added. As a device for applying shearing force, a seconder, an extruder, a disintegrator, etc. can be used.

The temperature during powdering may be room temperature, but it is 40-120℃.
It is more preferable to heat in a range of about 0.degree. C., and the pressure may be further reduced. Powdered glyoxal obtained by the method of the present invention is a hydrate of amorphous polyglyoxal in which several molecules of glyoxal are associated, and contains about 15 to 20% water, but about 15% is bound water. Therefore, it is a small amount of free water.

The final product is obtained by appropriately heating and drying the powder to remove the remaining user solvent.

The chemical properties of the obtained powdered glyoxal are not different from those of the raw material glyoxal, and therefore the deodorizing properties and other properties are not impaired in any way. Furthermore, such powdered glyoxal is a white powder, has low hygroscopicity even when left in the air, and has good solubility in water.
It is expected that new uses for the material will be developed. In carrying out the method of the present invention, it is of course possible to powderize glyoxal by appropriately mixing necessary auxiliary agents depending on the use of the glyoxal.

For example, when powdered glyoxal is used as a deodorant for circulating toilets on ships and vehicles, inorganic salts such as sodium nitrate, sodium sulfate, and acidic sodium phosphate, oxycarboxylic acids such as malic acid and citric acid, or dyes, etc. Can be mixed arbitrarily. Next, the method of the present invention will be explained in more detail by giving examples.

Example 1 A 1-horsepower stainless steel kneader with a charging volume of 51 and two rotary blades and a heating bath has a weight of 40? 2.5k9 of glyoxal aqueous solution was charged, and kneading was started at a rotational speed of 50 rpm, and dehydration was started while heating the bath to 85°C to 90°C.

The dehydration and concentration process will be explained with reference to FIG. In FIG. 1, -←→- indicates the change over time in the concentration of glyoxal, and 1←(generation) - indicates the change in the load of the kneader 1 (change in the current flowing through the ammeter connected to the kneader 1).

Three hours after the start of dehydration, the glyoxal concentration was 60% by weight and 70% by weight.
CA).

At this point, the concentrate has a viscosity of about 1 poise and is in a liquid state. Up until now, the load on the second one has been steady. As the viscosity gradually increases, the load begins to be applied to the secondary, and the concentration of glyoxal in the concentrate is 78% by weight? It turned into a rice cake shape (B). (The viscosity at this point was 15,000 poise and the applied shear force was 5 x 105 dynes/d.) At this point 1009 of toluene was added. Further dehydration continues, and glyoxal concentration is 80 weight? By the time (
In C), the viscosity of the cake-like material reached its maximum point, and at the same time, the load on the secondary plate also reached its maximum value.

Further, dehydration was continued by rotating the kneader 1, and when the temperature reached about 8270, the rice cake-like material began to solidify a little and began to break up into small lumps. As a result, the load on the secondary staff also decreased. Furthermore, by the time the point (E) was reached, the above-mentioned small lumps had changed to fine powder, and the load on the kneader had become constant, showing the same value as at the start of dehydration. After starting dehydration,
Glyoxal concentration 83 weight in about 6 hours? 1.2 kg of powdered glyoxal with a smooth particle size was obtained. Examples 2 to 6 Benzene (Example 2) was used instead of toluene in Example 1.
) (however, the bath temperature was 80 to 85 °C), xylene (Example 3)
) (however, the bath temperature was 90 to 95°C), ethyl acetate (Example 4)
) (however, the bath temperature was 75 to 80°C), dioxane (Example 5)
) (however, the bath temperature is 90-95℃), methyl ethyl ketone (
Example 6) (However, the bath temperature was 80 to 85°C) was carried out in the same manner as in Example 1, and powdered glyoxal was similarly obtained.

Example 7 The same method as in Example 1 was carried out except that the amount of toluene used was changed to 509.

Powdered glyoxal was obtained in good yield.

Example 8 In Example 1, when toluene was added when the concentration of glyoxal in the concentrate was 64 to 65% by weight? When the same experiment as in the same example was carried out except for the changes made in , powdered glyoxal was similarly obtained.

Control Example 1 The same experiment as in Example 1 was conducted except that the use of toluene was omitted.

The changes in this case are shown in FIG. In this example, the peak load applied to the secondary was extremely high compared to the example.

[Brief explanation of the drawing]

FIGS. 1 and 2 are graphs showing changes over time in glyoxal concentration and changes in load on the kneader over time when an aqueous glyoxal solution is dehydrated and concentrated.

Claims (1)

[Claims] 1. Temperature 80 obtained by concentrating glyoxal aqueous solution
A method for producing powdery glyoxal, which comprises applying a shearing force to a viscous material having a viscosity of 10,000 poise or more at °C in the presence of an organic solvent inert to glyoxal. 2. The manufacturing method according to claim 1, characterized in that shearing force is applied at a temperature of 40°C to 120°C. 3. The manufacturing method according to claim 1, wherein the organic solvent has a boiling point of 50°C to 150°C. 4. The production method according to claim 1, wherein the organic solvent is toluene.