JP2502361B2 - Melting pressure measuring device and melting pressure measuring method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting pressure measuring device, and more particularly, to a solid pressure measuring apparatus under the condition of a pressure load, when a temperature is kept constant and pressure is changed. It relates to a device for measuring the pressure of melting.

(Prior Art) The melting pressure is the pressure at which the solid precipitated by pressurization melts as described above, and the melting pressure is extremely important information when manufacturing or using a chemical substance under pressure.

For example, in the pressure crystallization method, which is attracting attention as a technique for separating and purifying a target component from a mixture, the melting pressure is essential information. The pressure crystallization method separates the crystal of the target component from other components from a liquid or slurry mixture by the action of high pressure, or precipitates the surface of the precipitated crystal (solid). This is because it is a separation and purification technology that seeks to obtain a highly pure product. That is, it is necessary that the pressure condition for precipitating the crystal or the melting pressure condition of the solid be known in advance.

In order to obtain the information on the melting pressure, the melting pressure is conventionally measured by the following apparatus and method.

That is, FIG. 2 shows a main part of a melting pressure measuring device which has been conventionally used. As shown in this figure, the conventional melting pressure measuring device has a piston (16) and a pressure-resistant container (17) in the main part, and the sample chamber (18)
Is formed. The above device has means (not shown) for measuring the pressure in the sample chamber (18),
The piston (16) is connected to a pressurizing means (not shown).

The measurement of the melting pressure by the above-mentioned device puts a sample (liquid) into the sample chamber (18), pressurizes it with a piston (16) to solidify it, and then lowers the pressure in the sample chamber (18),
It is performed by measuring the volume change amount (hereinafter referred to as ΔV) and the pressure (hereinafter referred to as P) in the sample chamber (18).
By doing so, the relationship between ΔV and P relating to the sample can be obtained. Therefore, if the value of the pressure at the point where the rate of change of P changes rapidly, that is, the discontinuity point is obtained from this P-ΔV diagram, the melting pressure will be Desired.

(Problems to be Solved by the Invention) However, the conventional melting pressure measuring device and method as described above have various problems as described below.

That is, the above-mentioned conventional method does not directly measure the melting pressure, but it is an indirect method that is obtained from the relationship between ΔV and P. Therefore, it is difficult to obtain an accurate melting pressure. It has a problem that it is bad. Also, theoretically, a discontinuity will appear at the melting pressure,
In reality, no clear discontinuity may appear and it may be recognized as a gradual change in the gradient, in which case the measurement accuracy becomes worse. Furthermore, depending on the type of substance (sample), it may not be possible to determine the melting pressure at all.

Further, a large amount of sample is required because the sample chamber is filled with the sample, or when a pipe for pressure measurement is connected to the sample chamber, the pipe is also filled with the sample. At least an amount that can fill the sample chamber is required. Although it is sufficient to make the sample chamber small, there is a limit to the reduction of the sample chamber because it is a system of pressurizing with a piston. For example, it usually requires at least several tens of cc of sample.

The sample for melting pressure measurement is naturally a new substance in many cases, and in that case, it is difficult to prepare a large amount of sample.
In addition, even if it is not a new substance, there are cases where there is only a small amount of sample.
Therefore, requiring a large amount of sample as described above is a very serious problem.

Further, when the pressure measurement pipe is connected to the sample chamber, and the sample in the sample chamber is in the solid state, the sample in the pipe is also in the solid state, and the pipe is clogged. Therefore, in this case, since the pressure in the sample chamber is not transmitted, there is a problem that it becomes difficult to measure the accurate pressure of the sample in the sample chamber.

The present invention has been made by paying attention to such a situation, and its object is to solve the above-mentioned problems of the conventional ones, the number of samples can be reduced, and the measurement accuracy is excellent.
It is intended to provide a melting pressure measuring device capable of measuring the melting pressure without fail even in a sample in which the discontinuity does not appear, and capable of accurately measuring the pressure of the sample even when a pipe for pressure measurement is provided. is there.

(Means for Solving the Problems) In order to achieve the above object, the melting pressure measuring device and the melting pressure measuring method according to the present invention have the following configurations. That is, in the method according to the first aspect, a liquid sample is placed in a pressure-resistant container having an optical window, the pressure in the container is increased and solidified, and then the pressure in the container is lowered. The melting pressure is measured while the pressure inside the container is measured and the sample is observed to determine the pressure at which the solid melts.

The apparatus according to claim 2 is a melting pressure measuring apparatus having a pressure-resistant container, a pressure increasing means for increasing the pressure in the container, and a pressure measuring means for measuring the pressure in the container,
The melting pressure measuring device is characterized in that an optical window made of a light transmitting body is provided on a side surface of the container. The apparatus according to the third aspect comprises a pressure-resistant container having an optical window made of a light-transmitting body on its side surface, a pressure increasing means for increasing the pressure inside the container, and a means for measuring the pressure inside the container. The melting pressure measuring device is characterized in that a sample chamber having elasticity and having a light transmissive window and having a sample sealed therein is arranged in a container. The apparatus according to the fourth aspect is the melting pressure measuring apparatus according to the third aspect, wherein the sample chamber is formed by a stretchable small container and the optical window. The melting pressure measurement according to claim 3, wherein the apparatus according to claim 5 is configured such that the sample chamber is formed of a stretchable small container provided with a light transmissive window on at least a side surface facing the optical window. It is a device. According to a sixth aspect of the present invention, a device for photographing an image is provided outside the optical window, a monitor television for displaying the photographed image, and a pressure-resistant container internal pressure and temperature are numerically displayed on the monitor television screen. Second having means for
The melting pressure measuring device according to claim 3, claim 3, claim 4 or claim 5. An apparatus according to claim 7 is characterized in that it has means for recording the photographed image.
The melting pressure measuring device according to the claim. Further, in the apparatus according to claim 8, optical windows are provided on opposite side surfaces of the pressure-resistant container, and means for measuring the amount of light transmission are provided outside the optical windows. And the melting pressure measuring device according to claim 4 or 5.

(Operation) In the melting pressure measuring method according to the present invention, as described above, since the liquid sample is placed in the pressure resistant container having the optical window, the sample in the container is optically converted. You can see through the window. Then, after the pressure inside the container is increased and solidified, the pressure inside the container is lowered, and the pressure inside the container is measured and the sample is observed, so that the melting of the solid is completed. Time pressure (ie melting pressure)
Can be requested. Since this pressure is obtained, the melting pressure can be measured reliably and accurately. Therefore, the measurement accuracy of the melting pressure can be made excellent. or,
It is possible to measure the melting pressure without fail even for a sample in which the discontinuity point of the P-ΔV diagram does not clearly appear.

A melting pressure measuring apparatus according to the present invention (apparatus described in claim 2) is a pressure-resistant container having an optical window made of a light-transmitting body on a side surface, and a pressure increasing means for increasing the pressure in the container.
Since it has a pressure measuring means for measuring the pressure in the container, the sample can be placed in the container and the same pressure operation and sample observation as described above can be performed. Therefore, as in the case described above, The melting pressure can be measured reliably and accurately.

In the melting pressure measuring device according to the third aspect, a sample chamber in which a sample is sealed is arranged inside the pressure-resistant container, and the volume of the sample chamber is naturally larger than the volume of the pressure-resistant container. Since it is small, the amount of sample can be reduced. Minimizing the volume of the sample chamber can greatly reduce the amount of sample. Also, the sample after observation needs to be completely washed and removed before the next observation sample is put in, but since only the sample chamber needs to be washed, it is relatively easy to wash and can be done in a short time. become. Alternatively, if the sample chamber is replaced as described below, cleaning can be unnecessary.

The sample chamber has elasticity and is provided with a light transmissive window, and has a pressure increasing means for increasing the pressure in the pressure resistant container. This is because the melting pressure can be measured as described below.

That is, when the pressure medium is injected into the pressure-resistant container via the pressure-resistant pipe by the pressure increasing means and then the pressure of the pressure medium is increased, the pressure in the sample chamber is increased because the sample chamber has elasticity. It can be equal to the pressure of the pressure medium. Also, since the sample is sealed in the sample chamber, contamination with the pressure medium cannot occur.
On the other hand, when light is irradiated from the optical window toward the sample chamber, the light passes through the light-transmissive window of the sample chamber and hits the sample in the sample chamber, so that the state of the sample can be observed. Therefore, when the pressure operation similar to the above is performed on the pressure medium and the sample is observed, the melting pressure can be measured reliably and accurately with high accuracy as in the case described above.

Regarding the sample chamber, in terms of accuracy of sample observation, it is desirable to form the sample chamber by the elastic small container and the optical window.
Because the sample is in contact with the optical window, the state of the sample can be observed more reliably. In this case, if the method of replacing the small container is used for cleaning, only the optical window needs to be cleaned. Therefore, cleaning is relatively easy and can be performed in a short time. In this case, the optical window (hereinafter referred to as the optical window A) is also used as the light transmitting window of the sample chamber.

In terms of ease of cleaning, it is desirable to form the sample chamber only by a stretchable small container provided with a light transmissive window on at least a side surface facing the optical window (optical window A). This is because the above cleaning may be performed only on the small container, and the cleaning time can be shortened. Also, if you replace the small container,
This is because it becomes unnecessary to wash. In this case, the sample chamber should be arranged close to the optical window from the viewpoint of sample observation accuracy. The sample chamber may be supported by a support, but the support is not always required.

In addition to the optical window A, an optical window (hereinafter referred to as another optical window) can be provided on the side surface of the pressure resistant container. In this case, if the small container is made entirely light-transmissive, or if a light-transmissive window is also provided on the side surface facing the other optical window, light is transmitted from the optical window A (or other optical window). The sample can be observed through the other optical window (or the optical window A) by irradiation.

The sample observation may be performed by visual observation, but in order to improve the observation accuracy and the easiness of the observation action, an image capturing means (TV camera) outside the optical window and a monitor displaying the captured image. It is desirable to have a television and means for numerically displaying the pressure and temperature inside the container on the monitor television screen. This is because when such a means is used, the image can be enlarged and the observation posture can be improved.

Further, it is more desirable to have a means (video camera) for photographing an image and recording the photographed image outside the optical window. Since the record remains, it is possible to reconfirm,
Alternatively, it becomes possible to automate the melting pressure measurement.

Alternatively, a means for measuring the amount of light transmission may be provided outside the optical window. Using this means, the melting pressure can be measured without visual observation. Since the melting pressure is the pressure when the solid disappears as described above, the light transmission amount of the sample before and after this suddenly changes, so the melting pressure can be measured by measuring this. Is. However, in this case, it is necessary to provide optical windows on both side surfaces of the pressure resistant container which face each other.

Regarding the material and shape of the optical window, any material can be used as long as it has optical transparency and required strength, and for example, hemispherical or cylindrical sapphire or the like can be used.

With respect to the stretchable small container, not all the parts of the small container need to be stretchable, but it is sufficient that the small container has stretchability in the necessary portion, and as a result, the small container can stretch.

The material of the stretchable portion may be, for example, silicone rubber or polyethylene, and is not particularly limited as long as it has stretchability. The shape of the small container may be, for example, a shallow rectangular parallelepiped with a flange, a hemispherical shape, or the like, or a partly having bellows, and is not particularly limited.

(Example) Example 1 FIG. 1 shows a side view of a melting pressure measuring apparatus according to Example 1. This device comprises a pressure-resistant container (3) portion, a pressure increasing means (4) portion, and a pressure-resistant pipe (6) portion connecting them. A pipe (5) for injecting a pressure medium is connected to the pressure increasing means (4).

Regarding pressure resistant container (3), (1) and (2) are containers (3)
Are optical windows made of sapphire provided on both opposite sides of the. The optical windows (1) and (2) are supported by an optical window pedestal (12), and the pedestal (12) is screwed to the pressure vessel (14). (13) is a seal member (O-ring).

(10) is a silicon rubber small container having elasticity and light transmission, and its flange portion is fixed to the end of the optical window (1) and its vicinity by a small container holder (11). As a result, an airtight sample chamber (9) is formed by the small container (10) and the optical window (1). A sample is sealed in the sample chamber (9).

Using the above-mentioned device, the melting pressure of a sample whose accurate melting pressure (hereinafter referred to as standard value) is known was measured. That is, the pressure medium is injected into the pressure increasing means (4) and filled in the pressure resistant container (3) (7) through the pressure resistant pipe (6). Meanwhile, the optical window (2) was irradiated with light from the light source (8) to start observation of the state of the sample. This observation was performed visually from outside the optical window (1).

Next, the pressure medium (15) was pressurized by the pressure increasing means (4) to pressurize the sample. It was observed that the small container gradually contracted as the pressurization proceeded. The pressure in the sample chamber (9) was measured with a strain gauge type pressure gauge (19) provided in the pressure resistant pipe (6).

After increasing the pressure to solidify the sample, the pressure in the container was lowered, the pressure in the container was measured, and the sample was observed to determine the pressure at which the solid melts. This melting pressure value is 0.2% higher than the standard value, which is an extremely accurate value. In the case of the conventional method used for comparison, the value was 2.5% higher than the standard value.

Example 2 FIG. 3 shows a side view of a melting pressure measuring device according to Example 2. The difference from Example 1 is that the optical window is only (1) and does not have the optical window (2), that the sample chamber is formed only by the elastic small container (10), and the optical window Light is emitted from a light source (8) arranged outside (1), and an optical window (1)
The state of the sample was observed with a reflection type optical microscope (not shown) arranged outside. The small container (10) has an upper wall (side surface facing the optical window (1)) made of a light transmissive material, and the other walls made of a stretchable non-light transmissive material. Others are Example 1
The melting pressure was measured in the same manner as in the above. as a result,
Melting pressure values similar to those of Example 1 were obtained.

(Effects of the Invention) According to the melting pressure measuring device or the melting pressure measuring method according to the present invention, the number of samples is small, the measurement accuracy is excellent, and the melting pressure can be measured without fail even for the samples that are difficult to measure by conventional methods. .

In addition, a complete cleaning of the device can be made relatively easy, or even unnecessary.

[Brief description of drawings]

FIG. 1 is a side view showing a melting pressure measuring device according to the first embodiment, FIG. 2 is a side view showing a main part of a conventional melting pressure measuring device, and FIG. 3 is a melting pressure measuring device according to the second embodiment. It is a side view shown. (1) ...... Optical window, (2) ...... Optical window (3) ...... Pressure resistant container, (4) ...... Pressure increasing means (5) ...... Piping, (6) ...... Pressure resistant piping (7) …… Inside the pressure resistant container, (8) …… Light source (9) …… Sample chamber, (10) …… Small container (11) …… Small container retainer, (12) …… Optical window pedestal (13) ) …… Seal member, (14) …… Pressure-resistant container (15) …… Pressure medium, (16) …… Piston (17) …… Pressure-resistant container, (18) …… Sample chamber (19) …… Pressure gauge

Claims (8)

(57) [Claims] 1. A liquid sample is placed in a pressure-resistant container having an optical window, the pressure in the container is increased and solidified, and then the pressure in the container is lowered and the inside of the container is reduced. A melting pressure measuring method, which comprises measuring a pressure and observing a sample to obtain a pressure at which a solid melts. 2. A melting pressure measuring device comprising a pressure-resistant container, a pressure increasing means for increasing the pressure in the container, and a pressure measuring means for measuring the pressure in the container. A melting pressure measuring device, characterized in that an optical window consisting of is provided. 3. A melting pressure measuring device comprising a pressure-resistant container having an optical window made of a light-transmitting body on its side surface, a pressure increasing means for increasing the pressure in the container, and a means for measuring the pressure inside the container. A melting pressure measuring device, characterized in that a sample chamber having elasticity and a light-transmissive window and having a sample sealed therein is arranged in the container. 4. The melting pressure measuring device according to claim 3, wherein the sample chamber is formed by a stretchable small container and the optical window. 5. The melting pressure measuring device according to claim 3, wherein the sample chamber is formed of a stretchable small container having a light transmissive window on at least a side surface facing the optical window. 6. An image capturing means for photographing an image outside the optical window, a monitor television for displaying the photographed image, and means for numerically displaying the pressure and temperature inside the pressure-resistant container on the monitor television screen. The melting pressure measuring device according to claim 2, claim 3, claim 4, or claim 5. 7. The melting pressure measuring device according to claim 6, further comprising means for recording the photographed image. 8. A second, a third, a fourth or a fourth aspect in which an optical window is provided on opposite side surfaces of the pressure-resistant container, and a means for measuring a light transmission amount is provided outside the optical window. The melting pressure measuring device according to claim 5.