JPH03165802A - Soxhlet extractor - Google Patents

Abstract

PURPOSE:To clearly detect the end of extraction by fitting a sensor for measuring the concn. of a substance to a return tube or a flask. CONSTITUTION:When a flask 2 is heated, a solvent 6 boils and the vaporized solvent 6 enters the upper part of an extracting part 9 and a reflux cooler 3 through a communicating tube 91 and a bypass 5. In the cooler 3, the solvent 6 liquefies by cooling, drops in cylindrical filter paper 8 and dissolves a desired substance contained in a solid sample 7. The resulting soln. flows in a return tube 4 through the filter paper 8 and drops in the flask 2. The solvent 6 in the flask 2 is always circulated by a pump 11 so that the solvent also flows in a bypass 12 for circulation and the concn. of the extract is measured with a sensor 10 and recorded with a printer, etc. By the above method, extraction work can be efficiently carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a Soxhlet extractor used to extract desired substances from solid samples. In particular, it relates to a Soxhlet extractor equipped with a sensor for detecting when extraction of a desired substance is complete.

(Conventional technology) The structure of a conventional Soxhlet extractor is shown in FIG.

The Soxhlet extractor 1 includes an extraction part 9, a reflux condenser 3 connected to the upper part of the extraction part 9, a flask 2 connected to the lower part of the extraction part 9, and the like. A communication pipe 91 for connecting to the flask 2 is provided at the lower part of the extraction part 9, and this communication pipe 91 and the upper part of the extraction part 9 communicate with each other through the side pipe 5. A return tube 4 is provided, which is located within the upper opening of the flask 2.

Next, a method of extracting a desired substance from a solid sample using such a Soxhlet extractor 1 will be described.

A cylindrical funnel 8 containing a solid sample 7 is placed in the extraction section 9.

A solvent 6 for extracting the substance contained in the solid sample 7 is placed in the flask 2. Heat flask 2 and add solvent 6.
is boiled, and the vaporized solvent 6 flows into the communication pipe 9l and the side pipe 5.
and enters the reflux condenser 3 connected to the upper part of the extraction section 9. Here, the solvent 6 is cooled and liquefied, and is dripped onto the thimble filter paper 8. The solvent 6 dropped onto the thimble 8 dissolves the desired substance contained in the solid sample 7, and this extract flows into the return tube 4 through the thimble 8.

When the extract liquid is filled to the top of the return tube 4, the liquid overflows, and the entire liquid passes through the return tube 4 and falls into the flask 2. By repeating such actions, the desired substance contained in the solid sample 7 is extracted.

(Problem to be solved by the invention) When extracting using such a Soxhlet extractor,
There is no way to know when the extraction is complete, so traditionally,
The end of extraction was decided through experience or trial and error. Therefore, there was a problem that the extraction was insufficient or that heating continued even though the extraction was completed.

The present invention solves the above problems, and its purpose is to provide a Soxhlet extractor that can clearly detect the end point of extraction of a desired substance.

(Means for Solving the Problems) The Soxhlet extractor of the present invention includes an extraction section in which a solid sample is accommodated, a reflux condenser connected to the upper part of the extraction section,
In a Soxhlet extractor equipped with a flask connected to the lower part of the extraction section and containing a solvent, and a return tube through which the extract flows down from the extraction section to the flask, the extract is placed in the return tube and/or the flask. The above object can be achieved by providing a sensor for detecting the concentration of a substance contained in the substance.

(Function) In a Soxhlet extractor in which a sensor is provided in the return tube, the concentration of substances contained in the extract passing through the return tube is detected by the sensor. The concentration detected by this sensor increases at the start of extraction, and as extraction continues, the concentration gradually decreases until the concentration of the extract is no longer detected. This indicates that the extraction is complete, so the extraction work is finished.

In a Fuchsle extractor, the flask is equipped with a sensor that detects the concentration of the solvent containing the extract. The concentration of the solvent gradually increases and reaches a substantially constant value, so the extraction operation is terminated at this point.

(Example) Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a schematic diagram showing the structure of a Soxhlet extractor 1 in which a sensor is provided at a portion where a liquid extracted from a desired substance falls from an extraction section to a flask.

In the figure, the Soxhlet extractor 1 includes an extraction part 9, a reflux condenser 3 connected to the upper part of the extraction part 9, and a flask 2 connected to a communication pipe 91 provided at the lower part of the extraction part 9. have. The extraction part 9 includes a side pipe 5 that communicates between the upper part of the extraction part 9 and the communication pipe 91, and a side pipe 5 that protrudes from the bottom of the extraction part 9 and extends to the connection part with the flask 2 in an inverted U shape. A return tube 4 having an extended tip is provided. The return tube 4 is provided with a sensor IO. The apex of the inverted U-shape in the return tube 4 is located below the upper connection position of the side pipe 5 and the extraction part 9. The diameter of the return tube 4 is generally set smaller than the diameter of the side tube 5. As the sensor 10, any sensor that can detect the concentration of substances contained in the extract can be used. For example 180-350
A combination of a light emitting element and a light receiving element that emits nm UV light is used. In this case, both elements are attached to the return tube 4 so that the extract passes between the light emitting element and the light receiving element, and the light receiving element receives the transmitted light emitted from the light emitting element and converts the light energy into electricity. convert into energy. The voltage value of the electrical signal obtained is proportional to the concentration of the extract.

Next, a method of extracting a desired substance contained in the solid sample 7 using the Soxhlet extractor 1 will be described. A cylindrical funnel 8 containing a solid sample 7 is placed in the extraction section 9. A solvent 6 for extracting the substance contained in the solid sample 7 is placed in the flask 2. When the flask 2 is heated, the solvent 6 boils, and the vaporized solvent 6 passes through the communication pipe 91 and the side pipe 5 to the upper part of the extraction section 9 and the reflux condenser 3. Here, the vaporized solvent 6 is cooled and liquefied, and is dropped into the thimble filter paper 8 to extract the desired substance contained in the solid sample 7. The extract flows into the return tube 4 through the thimble filter 8, and the concentration of the substance in the extract is
It is detected by the sensor IO and recorded on a printer (not shown) or the like. When the extract in which the desired substance has been dissolved is filled to the top of the return tube 4, it overflows and all of the extract passes through the return tube 4 and falls into the flask 2.

If this circulation of the solvent is repeated and the changes in concentration sequentially detected by the sensor 10 are represented in a graph, the third
A pseudocurve as shown by a in the figure is obtained. This pseudocurve is
At the start of extraction, the concentration of the extract in the liquid increases as the desired substance contained in the solid sample 7 is extracted, and then gradually as the content of the desired substance in the solid sample 7 decreases. and eventually become undetectable. The fact that it is no longer detected indicates that almost all of the desired substance has been extracted, and the extraction operation can be terminated.

As another embodiment of the present invention, a Soxhlet extractor 1 in which a sensor 10 is provided in a flask 2 is shown in FIG. The flask 2 used in this Soxhlet extractor 1 is equipped with a circulation side pipe 12. sensor 10
is provided in this circulation side pipe 12. In order to circulate the solvent 6 in the flask 2, the circulation side pipe 12 is provided with:
A pump 11 such as a rotary pump is provided. The rest of the structure is the same as the Soxhlet extractor l shown in FIG. 1, except that the sensor 10 provided in the return tube 4 is omitted.

A method of extracting a desired substance using such a Soxhlet extractor 1 will be described. The cylindrical filter paper 8 containing the solid sample 7 is placed in the extraction section 9, and the solvent 6 for extracting the substance contained in the solid sample 7 is placed in the flask 2. When the flask 2 is heated, the solvent 6 boils, and the vaporized solvent 6 passes through the communication pipe 91 and the side pipe 5 and enters the upper part of the extraction section 9 and the reflux condenser 3. Here, the vaporized solvent 6 is cooled and liquefied, drips into the thimble filter paper 8, and the solid sample 7
The desired substance contained in the solution is dissolved.

The extract containing the desired substance in the solid sample 7 passes through the cylindrical filter paper 8 and flows into the return tube 4 . When the liquid is filled to the top of the return tube 4, the liquid overflows, and all of the liquid passes through the return tube 4 and falls into the flask 2. Since the solvent 6 in the two flasks is constantly circulated by the pump 1l so that it also flows into the circulation side pipe 12, the concentration of the extract in the solvent 6 is detected by the sensor 10 and recorded on a printer (not shown) or the like. Ru. Since the extract is accumulated in the solvent 6 in the flask 2, as the concentration of the extract in the solvent 6 in the flask 2 changes,
A curve as shown in FIG. 3b is obtained. This curve b shows that at the start of extraction, the liquid containing the extract gradually increases.
As the concentration of the extract in the solvent 6 increases and the content of the desired substance in the extract decreases, it gradually stops changing and finally reaches a constant value. When the concentration reaches a constant value, it means that all the desired substance has been extracted, and the extraction operation can be ended at this point.

Note that a sensor may be electrically connected to a heater that heats the flask, so that heating by the heater is stopped when the value detected by the sensor becomes constant for a predetermined period of time.

(Effects of the Invention) By using the Soxhlet extractor of the present invention, it is possible to clearly know the end point of the extraction operation, so even if the extraction of the desired substance is incomplete or the extraction has already been completed. There is no need for continuous heating, allowing for efficient extraction work.

Since it can perform complete extraction operations, it can also be used to measure the purity of solid samples.

Figure 1 is a schematic diagram of one embodiment of the Soxhlet extractor of the present invention, Figure 2 is a schematic diagram of another embodiment of the Soxhlet extractor of the present invention, and Figure 3 is a schematic diagram of another embodiment of the Soxhlet extractor of the present invention. FIG. 4 is a graph showing the relationship between the concentration of the extract obtained as a result of using the Soxhlet extractor and time, and FIG. 4 is a schematic diagram of a conventional Soxhlet extractor.

■... Soxhlet extractor, 2... flask, 4...
...Return tube, 9...Extraction part, 10...Sensor, 12...Circulation side pipe.

Claims (1)

[Claims] 1. An extraction section in which a solid sample is accommodated; a reflux condenser connected to the upper part of the extraction section; a flask connected to the lower part of the extraction section and containing a solvent; A Soxhlet extractor equipped with a return tube through which a liquid flows from an extraction part to a flask, wherein the return tube and/or the flask is provided with a sensor that detects the concentration of a substance contained in the extract. .