JPS5920654B2 - 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 dissolved in water. As long as it is easily converted into an aqueous solution when added, 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 and 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, he 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 a glyoxal aqueous solution, and filed a patent application. I went.

That is, when a commercially available 4070 glyoxal aqueous solution is concentrated by heating and stirring under normal pressure or reduced pressure, when the glyoxal concentration reaches about 60%, it becomes a viscous liquid with a viscosity of about 1 void, and if the concentration is continued, The glyoxal concentration becomes about 70%, and the viscosity suddenly rises to over 100 poise, making it more like a sticky cake than a fluid. A normal stirrer cannot be used, and unless some kind of stirring is performed, it may cause discoloration or deterioration due to heating, so it is extremely difficult to further concentrate and solidify the product using normal methods.

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 applying shearing force to the viscous glyoxal that has been concentrated to the extent that it exhibits the above-mentioned mochi-like appearance, the mochi-like substance gradually loses its adhesive strength and becomes a brittle lump, and when further shearing force is applied, it becomes powdery. It becomes. This phenomenon occurs when the glyoxal aqueous solution is concentrated and the viscosity at a temperature of 80°C becomes 1000°C.
This occurs when shearing force is applied in a state where the viscosity is 0 poise or more, and powdering or embrittlement does not occur even if 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/d or more, and the greater the force and the longer the shearing force is applied, the more remarkable the effect will be. However, the properties of the resulting lumps differ depending on the magnitude of the shearing force and the duration of the shearing force; when the shearing force is large, the mochi-like material becomes a brittle lump, and if shearing force is applied continuously, the lumps gradually collapse. 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 glyoxal powder or polyglyoxal was added to 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. When applying shear force with powder present,
Compared to applying shear forces in the presence of powders as described above, the viscosity of the glyoxal concentrate is significantly reduced, reducing the load on the equipment to apply the same shear forces and requiring less power equipment. The present invention was completed based on the discovery that it is possible to powderize the powder, and that it can be powderized in a shorter time, resulting in significant practical effects.

The glyoxal powder or polyglyoxal powder used in the present invention may be produced by any method.

Products manufactured by the method of the present invention, products manufactured by the method previously applied by the applicant mentioned above, or products manufactured by the known methods described in (1), (2), and (3) above. Any of the following can be used. Such a powder having a particle size of about 300 to 1300 microns is advantageously used. If it is less than 300μ, there is a tendency that the effect of reducing the load on the device will not be sufficiently exhibited, while if it is more than 1300μ, it will be difficult to mix uniformly with the rice cake-like material, both of which will cause problems in practice.

The effect of the present application can be sufficiently obtained if the amount of glyoxal powder or polyglyoxal powder used is about 3% or more based on the weight of the viscous material, but preferably about 5 to 30% is most appropriate.

Even if it is used in an amount of 30% or more, there is no problem in powdering the powder, and it is possible to use such a large amount of powder, but it is not very preferable from an economic point of view or a work efficiency point of view.

There are no particular restrictions on the timing of adding the powder, and it may be added at any time; however, in the present invention, the purpose of using the powder is to facilitate the powdering of a sticky rice cake-like substance. 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.

It may be added during the concentration process of the aqueous glyoxal solution, but if the powder is added too far before the time of powderization, the added powder will dissolve in the existing water and the point of adding the powder will be lost. There is a risk that it will be completely lost. As a device for applying shearing force, a second machine, an extruder, a pulverizer, etc. can be used. The temperature during powderization may be room temperature, but it is more preferable to heat it in the range of about 40 to 120°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 2070% water, but about 15% bound water.
%, so it is a small amount of free water.

Since such powdered glyoxal is a white powder and has low hygroscopicity even when left in the air and has good solubility in water, it is expected that new uses for glyoxal will be developed. Incidentally, 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, kneading was started at a rotational speed of 50 degrees, and dehydration was started while heating the bath to 85°C to 90°C.

The state of dehydration and concentration will be explained according to FIG. In Figure 1, -←→- represents the change in glyoxal concentration over time.
1 (G) (Y) 1 indicates the change in the load of the secondary 1 (change in the current flowing through the ammeter connected to the secondary 1), respectively.
3 hours after starting dehydration, glyoxal concentration is 60 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 increased, a load began to be applied to the kneader, and the glyoxal concentration of the concentrate became 78% by weight and became cake-like (B). The viscosity at this point is 15,000 poise and the applied shear force is 5 x 103 dynes A? It was hot. At this point, 2009 powdered glyoxal (
grain? 300-800μ) was added. Further dehydration continues and glyoxal concentration is 80 weight? At around (C), the viscosity of the rice cake-like material reached its maximum point, and at the same time, the load on the kneader also reached its maximum value. Continue dehydration while rotating the secondary
By the time it reached about 8270, the mochi-like substance began to solidify a little, and at the same time, it began to break up into small lumps. As a result, the load on the secondary system 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 secondary had become constant, showing the same value as at the start of dehydration.
Approximately 6 hours after the start of dehydration, the glyoxal concentration was 83% by weight.
Powdered glyoxal with a smooth and uniform particle size of 0.1
．． 2k9 was obtained. Control Example 1 The same experiment as in Example 1 was conducted except that the use of powdered glyoxal 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 drawings]

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 powdered 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 glyoxal powder or polyglyoxal powder. 2. The manufacturing method according to claim 1, characterized in that shearing force is applied at a temperature of 40°C to 120°C.