JPH06157370A - Method for preventing p-dichlorobenzene from consolidating - Google Patents

Abstract

PURPOSE:To stabilize the quality in storing or transporting solid p- dichlorobenzene and prevent the consolidation thereof by controlling the p- dichlorobenzene to a prescribed temperature or below. CONSTITUTION:Solid p-dichlorobenzene which is a flaky product or its pulverized, recrystallized or granular product is stored or transported. In the process, the solid p-dichlorobenzene is controlled under temperature conditions of <=35 deg.C to prevent the p-dichlorobenzene from consolidating. Furthermore, a consolidation preventing agent such as a surfactant is preferably added to the solid p-dichlorobenzene.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for preventing p-dichlorobenzene from solidifying. More specifically, the present invention provides a method for preventing caking when storing or transporting a solid p-dichlorobenzene product.

[0002]

2. Description of the Related Art p-Dichlorobenzene (hereinafter referred to as PDCB
Is abbreviated. ) Is generally molded into a tablet shape, a ball shape, or a rod shape, and is widely used as an insect repellent or a deodorant for clothing and the like. In addition, it has recently been used as a raw material for certain polymer materials.

[0003] PDCB is generally separated and purified from a mixture of chlorobenzene, o-dichlorobenzene, p-dichlorobenzene, etc. obtained by chlorination using benzene as a raw material, and then shipped to a molding maker in the form of flakes or granules. Has been done.

By the way, PDCB has a low melting point of 53 ° C. even in a pure product, although it varies depending on the content of a trace amount of impurities, and since it has a sublimation property, the molecular motion on the particle surface is vigorous. It inherently has the property of being easily consolidated during transportation. Once solidified, the workability of a molding manufacturer is significantly deteriorated. In order to solve such a PDCB consolidation problem, various measures have been conventionally made. As a typical method,
A method of adding a certain compound or the like to prevent caking is known.

For example, Japanese Patent Publication No. 42-10942 and Japanese Patent Publication No. 42-1006 disclose a surfactant, and Japanese Patent Publication No. 58-134037 and Japanese Patent Publication No. 1-34207 disclose a volatile silicone oil. The Japanese Examined Sho 57-4615
Japanese Patent Publication No. 58-238
No. 51 discloses a diethylene glycol derivative, and Japanese Patent Publication No. 58-11406 discloses a combination of benzyl alcohol and a diethylene glycol derivative in PDCB.
It is described that the addition of PDCB has a great effect on preventing the solidification of PDCB. In addition, the applicant of the present application also investigated various new additives for preventing such caking, and found out additives such as tetraalkoxysilanes, certain triethylene glycol derivatives, or phenoxybenzyl alcohols. I applied.

The present inventors have confirmed that the additives found in these prior arts are compounds which are effective in preventing the solidification of PDCB, although their effects are different. However, in the process of subsequent studies, the inventors of the present invention may significantly increase the caking strength of PDCB containing these additives for preventing caking during storage of the product. It was found that shipping to a tableting maker may significantly deteriorate the workability during tableting and the quality of PDCB tableted products.

Occasionally, such a phenomenon is caused by the PDC.
Naturally, it is not preferable for the tableting maker of B, and it can be said that there is no dispute that it is a necessary condition for the manufacturer of PDCB to always provide a PDCB that does not have any problems.

[0008]

According to the present invention, even a PDCB product containing a known anti-caking agent is significantly solidified in the process of storage and transportation thereof, which results in workability in a tablet maker and tableting. Preventing deterioration of product quality,
It is to provide a stable PDCB product.

[0009]

As a result of various studies on the cause of remarkable solidification of PDCB as described above, the inventors of the present invention have found that when the temperature for storing the product exceeds 35 ° C., an additive for preventing solidification is added. It has come to the very interesting finding that the solidification force of PDCB increases exponentially with or without.

That is, various PDCs containing known additives
How does the cohesive strength change when B and the flakes of PDCB to which no additive is added are left in a product form and various temperatures are changed and a load of constant weight is left for a predetermined time. As a result of the examination, it was found that the solidification force did not increase so much up to 35 ° C., but the solidification force rapidly increased at 40 ° C. By the way, PDCB with triethylene glycol diacetate added as an additive
The relationship between the temperature and the caking force of the flakes (crushed product) (see the example for the measuring method) is 70 g at 25 ° C., 90 g at 30 ° C., 120 g at 35 ° C., but 456 at 40 ° C.
The value was about 40 times that of 0 g and the setting force at 35 ° C.

As described above, the phenomenon in which the solidification force of PDCB sharply increases when the temperature is higher than about 35 ° C. has not been known so far, and was found for the first time by the present inventors. Therefore, it was found that storage or transportation after production requires temperature control at 35 ° C. or lower in order to stabilize the quality of PDCB, particularly to prevent caking, and thus reached the present invention.

That is, the present invention is a method for preventing solidification of p-dichlorobenzene, which is characterized by maintaining a temperature condition of 35 ° C. or lower when storing or transporting solid p-dichlorobenzene. The PDCB in the present invention is a solid product, and the shape thereof is not particularly limited, and examples thereof include flakes or crushed products thereof, recrystallized products, or granular products.

The PDCB of the present invention is applicable to both the ones to which a known anti-caking agent is added and those to which the anti-caking agent is not added.

The anti-caking agent in the PDCB to which the anti-caking agent is added is not particularly limited as long as it is publicly known, and specifically, various surfactants, volatile silicone oils, benzyl alcohols. , Diethylene glycol derivatives such as diethylene glycol monobutyl ether acetate and diethylene glycol dibutyl ether,
Examples thereof include triethylene glycol derivatives such as triethylene glycol and triethylene glycol diacetate, tetraalkoxysilane compounds, cyclic organic amide compounds, phenoxybenzyl alcohols, and inorganic compounds such as silica and alumina.

In the present invention, by controlling the temperature of the PDCB during storage or transportation to 35 ° C. or lower, preferably 30 ° C. or lower, the solidification of PDCB is prevented.
Exposure to a temperature condition exceeding 35 ° C. is not preferable because the solidification of the product PDCB is significantly promoted regardless of the presence of the anti-caking agent.

[0016]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Here, the caking force was measured as follows.

[Measurement of Consolidation Force] Various solid PDCBs were loaded into a cylindrical container having an inner diameter of 5 cm and which was cut up and down, and a load of 1 kg was applied to the solid PDCB from above to cover the whole with a vinyl bag. After leaving it for 15 hours at a given temperature, remove the covering plastic bag, remove the load, then fix the lower part of the cylinder and pull the upper cylinder horizontally.
The force when the upper cylinder started to move was measured, and this force was used as the consolidation force. Incidentally, in detail, this cylindrical container is made of resin, and the lower cylindrical container stands vertically on a flat plate, and the lower part of the container is fixed in close contact with the surface of the plate. . The upper cylindrical container is placed on top of the lower cylindrical container. The solid PDCB is placed in the upper and lower cylindrical containers thus combined. Also, 30
In measuring the caking force under a temperature condition of ℃ or more, a method of measuring the caking force at room temperature after leaving it in a heat-retaining chamber set to a predetermined temperature was adopted.

Examples 1 to 3 and Comparative Example 1 PDCB flakes produced by adding 0.1% by weight of triethylene glycol diacetate to PDCB (crushed product, mainly having a particle size of 5 to 20 mesh) The relationship between temperature and solidification force was investigated. The results are shown in Table 1 (Table 1).
Shown in.

[0019]

[Table 1]

Examples 4-6, Comparative Example 2 0.05% by weight of diethylene glycol monobutyl acetate and 0.0% of benzyl alcohol based on PDCB.
The relationship between the temperature and the cohesive force was examined for the flakes of PDCB (crushed product, the particle size of which is mainly 5 to 20 mesh) to which 5 wt% was added. The results are shown in Table 2 (Table 2).

[0021]

[Table 2]

Examples 7 to 12 and Comparative Examples 3 to 4 The temperature and solid content of flakes of PDCB (without additives) (crushed to a main particle size of 5 to 20 mesh) and recrystallized products from ethanol. I investigated the relationship of cohesion. The results are shown in Table 3 (Table 3).

[0023]

[Table 3]

[0024]

According to the method of the present invention, unexpected solidification of PDCB can be prevented only by controlling the temperature at the time of storage or transportation. Therefore, it is industrially extremely effective in quality control of products. It's a big and valuable way.

Claims (3)

[Claims] 1. A method for preventing solidification of p-dichlorobenzene, which is characterized by controlling the temperature condition at 35 ° C. or lower when storing or transporting solid p-dichlorobenzene. 2. The p-dichlorobenzene is a flake product, a crushed product thereof, a recrystallized product or a granular product.
The method described. 3. The method according to claim 1, wherein the solid p-dichlorobenzene contains a known anti-caking agent.