JP4417802B2 - Method for inhibiting deterioration of organic compounds - Google Patents

Description

  The present invention relates to a method for suppressing deterioration of an organic compound contained in a container, for example, a method for suppressing deterioration of an organic compound used for cleaning an instrument to which a synthetic resin material adheres.

Conventionally, organic compounds are used in various applications. For example, Patent Documents 1 to 3 disclose that ethylene glycol, which is an organic compound, is used for cleaning an instrument to which a synthetic resin material is attached. On the other hand, photocatalysts are also used for various applications. For example, Patent Document 4 discloses using a photocatalyst for purification of fluids such as oil, water, and air for frying.
JP 2002-186918 A JP-A-57-91715 Japanese Patent Publication No.49-11636 JP 2002-316056 A

  By the way, an organic compound is recognized as being easily deteriorated because it undergoes thermal decomposition, oxidation, and the like due to factors such as aging and heating. For example, the ethylene glycols in Patent Documents 1 to 3 are recognized as being easily decomposed and easily deteriorated due to heating during cleaning. Such repeated use of ethylene glycol, which is prone to degradation, is difficult, and as a result, ethylene glycol must be changed frequently. On the other hand, in Patent Document 4, only the idea of using a photocatalyst for fluid purification is disclosed.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a method for suppressing deterioration of an organic compound that can easily suppress deterioration of the organic compound contained in the container.

In order to achieve the above object, a method for inhibiting deterioration of at least one organic compound selected from ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol according to the invention of claim 1 is accommodated in a container. The present invention provides a method for suppressing deterioration of an organic compound, wherein a photocatalyst is added in the container so as to contact the organic compound, and the inside of the container is made an electromagnetic wave atmosphere.

The method of the degradation inhibiting organic compounds of the invention of claim 2 is the invention according to claim 1, wherein the organic compound is the gist and Turkey used to clean instruments polyester adhered.

According to a third aspect of the present invention, there is provided an organic compound deterioration inhibiting method according to the first or second aspect, wherein the container is an autoclave .

  According to the present invention, it is possible to easily suppress the deterioration of the organic compound accommodated in the container.

Hereinafter, an embodiment in which the present invention is embodied in a method for suppressing deterioration of a cleaning oil used for cleaning an instrument to which polyester is attached will be described in detail.
In this embodiment, the instrument is cleaned using a container. That is, the container contains cleaning oil that is an organic compound. And the said washing | cleaning is removing the polyester adhering to an instrument by throwing the said instrument in a container and immersing the instrument in washing | cleaning oil. The instrument is used for the production of polyester and polyester products, and specific examples include a reactor and the like in addition to a filter and piping. The polyester contains 50% by mass or more of a polyester of an aromatic dicarboxylic acid or its ester and glycol as a main component.

  As the container, a container having a sealing property is usually used for the purpose of preventing scattering of cleaning oil during cleaning. Furthermore, the container preferably has either heat resistance or pressure resistance so that the internal temperature and pressure can be increased in order to increase the cleaning efficiency of the instrument, and has both heat resistance and pressure resistance. More preferred. The temperature in the container at the time of washing is preferably slightly lower than the boiling point of the washing oil, and the pressure is preferably from 0.1 to 1.0 MPa. In this embodiment, an autoclave is used as a container having both heat resistance and pressure resistance.

  The cleaning oil removes the polyester from the instrument. In addition, as the cleaning oil, in order to efficiently remove the polyester from the instrument, those having solubility in polyester are preferable, and those having an alcohol component (hydroxyl group) in the molecule are more preferable.

  Examples of the cleaning oil include aliphatic polyhydric alcohols such as ethylene glycols and glycerin, silicone oils, fluorine oils, and fats. Examples of ethylene glycols include ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol. Examples of the fats and oils include vegetable oils such as coconut oil and palm oil, and animal fats and oils such as fish oil, beef tallow and butter fat. These cleaning oils may be used alone for cleaning the appliance, or two or more may be used in combination for cleaning. Among these, ethylene glycols are preferable, and triethylene glycol is more preferable.

  Among the washing oils, ethylene glycols are soluble in polyester and have an alcohol component in the molecule. For this reason, in addition to the solubility with respect to the said polyester, ethylene glycols also have the decomposability | degradability with respect to polyester resulting from an alcohol component. Therefore, ethylene glycols can be dissolved while decomposing polyester, and polyester can be efficiently removed from the instrument to increase the cleaning efficiency of the instrument, which is suitable as a cleaning oil. Further, among ethylene glycols, triethylene glycol has high solubility and degradability with respect to polyester.

  In the container, a photocatalyst is added in contact with the cleaning oil in order to suppress the deterioration of the cleaning oil. Here, the addition of the photocatalyst may be performed by placing the photocatalyst in a container such as by immersing it in cleaning oil, or coating the photocatalyst film on the inner surface of the container, or placing the photocatalyst in the container. You may carry out by filling in the side wall of this. When the photocatalyst is filled in the side wall of the container or the like, a part of the photocatalyst is exposed from the inner surface of the side wall or the like.

  This photocatalyst exhibits a photocatalytic action such as a reducing action in an electromagnetic wave atmosphere, and suppresses deterioration of the cleaning oil contacted by the photocatalytic action. This is presumably because the cleaning oil in contact with the photocatalyst is suppressed from thermal decomposition and the like by the photocatalytic action. And the said container makes electromagnetic wave atmosphere the inside, in order to make a photocatalyst exhibit a photocatalytic action. In order to make the inside of the container have an electromagnetic wave atmosphere, a device that radiates electromagnetic waves may be attached to the inside of the container, or the side walls may be formed of a material that can transmit electromagnetic waves, and the electromagnetic waves may be irradiated from the outside. Good. Examples of electromagnetic waves include gamma rays, X-rays, ultraviolet rays, visible rays, infrared rays, radio waves, and the like.

Examples of the material for the photocatalyst include titanium oxide (TiO ₂ , Ti ₂ O ₃ ), tin oxide (SnO ₂ , SnO), and zinc oxide (ZnO). The shape of the photocatalyst is a spherical particle shape, a linear shape, or a lattice shape. Etc. The photocatalyst may be formed only of the material, or may be formed by coating the surface of titanium particles or the like with a photocatalyst film made of the material. The photocatalyst film is coated, for example, by melting and adhering titanium powder to the surface of the titanium particles. At this time, the surface of the titanium particles is coated with a photocatalytic film composed of titanium oxide resulting from oxidation of titanium during the melt adhesion. Here, the photocatalyst has a structure in which the proportion of oxygen bonded to the metal decreases from the outer surface toward the inside (hereinafter referred to as an oxygen-deficient gradient structure), and the container has an external electromagnetic wave on the side wall. It is preferable to be configured so as to penetrate the inside and the like. Here, the photocatalyst having an oxygen-deficient gradient structure exhibits a photocatalytic action in response to radio waves having a wavelength longer than that of ultraviolet rays. Further, the radio waves and the like are usually radiated into the atmosphere. For this reason, by making the said electromagnetic wave etc. reach the inside of a container, deterioration of cleaning oil can be suppressed by utilizing these electromagnetic waves etc. effectively. Therefore, it is not necessary to attach a device for irradiating the electromagnetic wave to the container, and the structure of the container can be simplified.

The contact area between the photocatalyst and the cleaning oil is preferably 500 to 1000 cm ² . If the contact area is less than 500 cm ^2, it may take a long time to suppress the deterioration of the cleaning oil, and the efficiency may decrease. If the contact area exceeds 1000 cm ² , the efficiency for suppressing deterioration cannot be further increased. When the photocatalyst is immersed in the cleaning oil, the contact area is the same as the surface area of the photocatalyst.

  Now, when washing | cleaning the said instrument, cleaning oil and a photocatalyst are accommodated in an autoclave. Next, the instrument is accommodated in the autoclave and the inside of the autoclave is heated. In the autoclave, when the temperature becomes close to the boiling point of the cleaning oil, the cleaning oil evaporates and the pressure rises. The equipment in the autoclave is cleaned with the polyester removed by the cleaning oil. Thereafter, the temperature and pressure in the autoclave are returned to the original values, and the instrument is taken out from the autoclave. Each time a new instrument is cleaned, the inside of the autoclave is heated and pressurized, and the cleaning oil tends to deteriorate. Here, since the photocatalyst is accommodated in the autoclave, the photocatalyst exhibits photocatalytic activity by electromagnetic waves. For this reason, the cleaning oil is prevented from being deteriorated, and the cleaning ability is maintained for a long time.

The effects exhibited by the above embodiment will be described below.
-The degradation suppression method of embodiment adds a photocatalyst in a container and makes the inside of the container the electromagnetic wave atmosphere. The photocatalyst exhibits photocatalytic activity by electromagnetic waves. For this reason, deterioration of the cleaning oil is effectively suppressed by the photocatalytic action of the photocatalyst. Therefore, when the cleaning oil is repeatedly used for cleaning the appliance, the replacement frequency thereof can be reduced as compared with the conventional cleaning oil.

Next, the embodiment will be described more specifically with reference to test examples and comparative examples.
(Examples 1 and 2 and Comparative Example 1)
In Example 1, 1200 liters (1350 kg) of triethylene glycol as a cleaning oil was contained in an autoclave (inner diameter: 1000 mm and height: 2500 mm) as a container, and a spherical photocatalyst (diameter: 15 mm, Material: SnO ₂ ) was added to the cleaning oil and allowed to stand for 24 hours.

Here, as the photocatalyst, one formed of SnO ₂ and having an oxygen-deficient gradient structure was used. The photocatalyst was stored in a storage bag formed of a wire mesh and suspended on the inner surface of the autoclave. 2.5 kg of photocatalyst was stored in the storage bag. Three storage bags were hung on the inner surface of the autoclave. In addition, all photocatalysts were immersed in triethylene glycol. The amount of photocatalyst contained in the autoclave was 7.5 kg, and the total surface area was 84820.5 mm ² (848.205 cm ² ).

  Next, the instrument with the polyester attached was accommodated in an autoclave and allowed to stand for 1 hour, and then the interior of the autoclave was heated to 265 ° C. to clean the instrument. At this time, the pressure in the autoclave increased with heating. Subsequently, the pressure in the autoclave when the temperature in the autoclave reached 265 ° C. was measured, and heating was stopped and natural cooling was performed. Next, the instrument was taken out from the autoclave, a new instrument was accommodated, and washing was repeated.

In Example 2, the instrument was cleaned in the same manner as in Example 1 except that the material of the photocatalyst was changed to TiO ₂ . On the other hand, in Comparative Example 1, the instrument was washed in the same manner as in Example 1 except that no photocatalyst was added to the autoclave. In Example 1 and Comparative Example 1, the measurement result of the pressure in the autoclave when the temperature in the autoclave reaches 265 ° C. is shown in FIG.

  As shown in FIG. 1, in Example 1, the pressure in the autoclave could be stabilized within a certain range after increasing the pressure in the autoclave to about 0.5 MPa with the repeated cleaning of the instrument. In Example 2, although not shown, the same results as in Example 1 were obtained. Furthermore, in Examples 1 and 2, it was necessary to replace the triethylene glycol in the autoclave after cleaning the instrument 16 times. This was because the polyester removed from the device was dissolved in a large amount in triethylene glycol, so that the polyester dissolved in the cleaned device was easily reattached.

  On the other hand, in Comparative Example 1, the pressure in the autoclave increased with an increase in the number of times the instrument was cleaned. Furthermore, in Comparative Example 1, it was necessary to replace the triethylene glycol in the autoclave after cleaning the instrument 12 times. This was because the pressure in the autoclave increased excessively during instrument cleaning.

  Here, triethylene glycol deteriorates due to thermal decomposition with an increase in the number of times the appliance is cleaned, that is, with an increase in the number of repetitions of heating in the autoclave. At this time, in the autoclave, a decomposition product of triethylene glycol having a boiling point lower than that of triethylene glycol is generated by thermal decomposition of triethylene glycol. In the autoclave, the amount of the decomposition substance increases with the progress of deterioration of triethylene glycol, and the pressure at 265 ° C. increases. For this reason, in Comparative Example 1, it is considered that the degradation of triethylene glycol progressed with an increase in the number of times the instrument was cleaned. On the other hand, in Examples 1 and 2, since the pressure in the autoclave was stabilized within a certain range, it is considered that the degradation of triethylene glycol was suppressed as compared with Comparative Example 1.

In addition, this embodiment can also be changed and embodied as follows.
-In the said Example, washing | cleaning of an instrument may be performed continuously and may be performed every predetermined time. When the instrument is continuously cleaned, the degradation of triethylene glycol is suppressed during cleaning. In addition, when the instrument is cleaned at predetermined intervals, the degradation of triethylene glycol is suppressed during each cleaning operation or during cleaning.

-The polyester may be changed to polypropylene, nylon or the like. That is, the cleaning oil may be used for cleaning an instrument to which a synthetic resin material other than polyester is attached .

  In addition to the photocatalyst, a polyester depolymerization catalyst such as sodium hydroxide may be accommodated in the container. When comprised in this way, the washing | cleaning efficiency of an instrument can be improved more.

Further, the technical idea that can be grasped from the embodiment will be described below.
The deterioration of the organic compound according to any one of claims 1 to 3, wherein the photocatalyst has an oxygen-deficient inclined structure, and the container is configured such that an external electromagnetic wave reaches the inside. Suppression method. According to this configuration, the configuration of the container can be simplified.

And deterioration suppressing method of the organic compound according to claim 1 of ethylene glycol is triethylene glycol. According to this configuration, the cleaning efficiency of the instrument can be further increased.

The graph which shows the measurement result of the pressure in the autoclave in Example 1 and Comparative Example 1. FIG.

Claims (3)

A method for inhibiting deterioration of at least one organic compound selected from ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol contained in a container,
A method for inhibiting deterioration of an organic compound, wherein a photocatalyst is added to the container so as to contact the organic compound, and the container is filled with an electromagnetic wave atmosphere. The organic compound is, deterioration suppressing method of the organic compounds described 請 Motomeko 1 that is used for cleaning instruments polyester adhered. The method for suppressing deterioration of an organic compound according to claim 1, wherein the container is an autoclave .

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