JPH032563A - Automatic analyzer for soap - Google Patents

Abstract

PURPOSE:To quantitatively analyze soap automatically in a short time with high precision by utilizing absorptiometry in the measurement of the free alkali or fatty acid in a soap soln., and utilizing potentiometric titration in the measurement of the pure soap content. CONSTITUTION:A soap soln. is firstly sampled in an analytical cell 1, and the weight of the sample is measured by a load cell 2. An indicator soln. dispenser 6 is then filled with the soln. in an indicator soln. tank T1, a fixed amt. of the soln. is injected into the cell 1 to the level E2 of a level electrode 4, and the soln. is agitated by an agitator 5 and colored. The colored soln. is then introduced into a photocell 8, and the absorbance of the soln. is measured by a photoisolator 9 and calculated 10 to obtain the content of free alkali. The soap soln. is further sampled in the cell 1, the weight of the sample is measured by the load cell 2, and the isopropyl alcohol in a soln. tank T3 is injected into the cell to the level E2 of the level electrode 4 and agitated by the agitator 5. Under such conditions, the soap soln. is titrated by aq. hydrochloric acid. The point of neutralization is detected by a pH electrode 3, and the titre is calculated 10 to obtain the pure soap content.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for automatically measuring the free alkali or free fatty acid content and pure soap content in a soap solution in a soap manufacturing process.

[Conventional technology]

The quantitative analysis method for free alkali and pure soap in soap is based on the Japanese Industrial Standards (JIS K 3304-1983).
stipulated in That is, free alkali is obtained by heating and dissolving a sample in 99.5% by weight neutral ethanol, and
Determined by titration with 0 ethanolic hydrochloric acid.

In addition, for pure soap, the sample was heated and melted in water, transferred to a separating funnel, acidified with IN sulfuric acid or IN hydrochloric acid to decompose the soap, extracted with petroleum ether, and the petroleum ether was distilled off from the extract. The residue is titrated with an N/2 ethanolic potassium hydroxide solution to the neutralization point, the ethanol is distilled off, and after drying, the weight is weighed to determine the pure soap content.

In addition, as a quantitative analysis method different from the Japanese Industrial Standards, there is the West German DGF standard test method, which is a quick method for determining the pure soap content by titrating the alkaline content in soap with a hydrochloric acid solution. known as law.

On the other hand, as a process analysis, Italian Patent No. 7219
640, there is also known a method of measuring free alkali or free fatty acids from a reaction system of fatty acids and sodium hydroxide using a milliportometer.

[Problem to be solved by the invention]

However, the analysis method according to the Japanese Industrial Standards and the analysis method according to the DGF standard test method are both manual methods, and therefore are not suitable for manufacturing process analysis performed by taking samples from the manufacturing process at any time.

In particular, the former free alkali analysis method has problems such as requiring a long time for dissolution when the water content of the sample is low and requiring skill in determining the end point. In addition, the former method for analyzing pure soap requires more complicated operations, and therefore cannot be used for process control.

On the other hand, the method of measuring free alkali or free fatty acid using a millivoltmeter, which has been proposed for manufacturing process analysis, has the drawback that it is difficult to accurately analyze minute amounts of alkali or fatty acid near the neutralization point.

In view of the above-mentioned circumstances, the present invention provides an automatic analyzer that can automatically quantify free alkali or free fatty acids and pure soap content in a soap solution collected from a soap manufacturing process in a short time and with high precision. It is intended to.

[Means to solve the problem]

As a result of intensive studies to achieve the two objectives, the inventors of the present invention have decided to utilize spectrophotometry to measure free alkalis or free fatty acids in soap solutions, and to use potential difference methods to measure pure soap content. By using the titration method, it is possible to perform automatic and highly accurate quantitative analysis in a short period of time, and we have discovered the key to providing an automatic analyzer suitable for process control analysis, and have completed the present invention. It's arrived.

That is, the present invention adds an indicator that develops color by reacting with free alkali or free fatty acids to a fixed amount of soap solution collected from the soap manufacturing process, and then determines the free content in the soap solution based on the absorbance of the colored solution. A quantitative mechanism for automatically measuring the amount of alkali or free fatty acids, and a constant ffl[J mechanism for automatically measuring the pure soap content in the core soap solution by potentiometric titration of the soap solution with a hydrochloric acid solution. This relates to an automatic stone analyzer.

[Structure and operation of the invention]

The quantitative analysis mechanism for free alkali or free fatty acids in the automatic analyzer of the present invention uses an appropriate reagent that develops color by reacting with these components, and the solution when a certain amount of the reagent is added to a certain amount of soap solution. Utilizing the fact that the degree of color development is correlated with the content of the bipedal component, this degree of color development is measured as absorbance by spectrophotometry, and the content is determined from this measured value.

In addition, in order to determine the content of free alkali or free fatty acid in a soap solution from the measured value of absorbance, create a calibration curve that examines the relationship between the content of these components and absorbance in advance, and use this calibration curve. What is necessary is just to determine the said content from comparison with a measured value.

Examples of the reagent for developing the color include phenolphthalein, cresol red, or a mixture thereof. Particularly preferred is a mixture of phenolphthalein and cresol red in a weight ratio of about 1:0.01 to 0.05. It is. A suitable reagent such as isopropyl alcohol? Container G is added to and mixed with the above soap solution as a dissolved solution.

Absorbance is normally measured by storing a colored solution in a photocell and using a photoelectric colorimetric method that uses an interference filter, an optical filter, and an optical sensor, but other absorbance measurement methods can also be used. Adoptable. When using the above mixture of phenolphthalein and cresol red as reagents, a 580 nm interference filter is used in the two-legged photoelectric colorimetric method.

On the other hand, the mechanism for determining pure soap content in the automatic analyzer of the present invention is to potentiometrically titrate a soap solution collected from a soap manufacturing process with a hydrochloric acid solution. In this case, in order to avoid gelation of the collected soap solution at low temperatures and cloudiness of the solution after dropping, and to increase titration accuracy, perform titration after diluting the above soap solution with a solvent such as isopropyl alcohol. is desirable.

In order to calculate the content of each component from the absorbance measurement value and potentiometric titration value obtained by the above-mentioned fixed amount mechanism, a microcomputer may be used to automatically calculate the content. That is, a controller device is attached to the automatic analyzer, and the measured absorbance value and the potentiometric titration value are sent as electrical signals to the controller, and the controller calculates the above absorbance value based on a calculation program input in advance. The measured values and potentiometric titration values are converted into free alkali or free fatty acid content and pure soap content.

The content converted in this way may be displayed on a CRT display or printer.

The automatic analyzer of the present invention can be designed into various structures incorporating the above fixed amount mechanism. In particular, from the viewpoints of simplifying, compacting, and functionality of the device configuration, an analysis cell containing the collected soap solution is placed in a fixed position, and an indicator solution for coloring is placed inside this fixed position analysis cell. , piping to inject hydrochloric acid solution for titration and solvent for dilution, piping to send the liquid after coloring to the photocell,
Install piping to discharge the analyzed liquid from the analysis cell to the outside of the system.
Additionally, a pH electrode, liquid level electrode, stirrer, etc. are attached.
A structure is recommended in which the color reaction for potentiometric titration and absorbance measurement is performed in the analytical cell in the fixed position.

In addition, in the above structure, in order to avoid the influence of components remaining attached in the analysis cell after analysis on the next analysis,
It is desirable to inject a cleaning liquid into the analysis cell to clean it after each analysis.

As for the method of collecting the soap solution that becomes the analysis sample, it is also possible to adopt a method in which a sample injection tube is led out from the soap manufacturing process and the soap solution is directly injected into the analysis cell at the above fixed position.
It is preferable to use a system in which the analysis cell is automatically moved between the above-mentioned fixed position for analysis and the sample collection position from ``Device Configuration''. Furthermore, in order to automatically weigh the collected sample, a load cell may be attached to the analysis cell.

〔Example〕

Next, one embodiment of the automatic analyzer of the present invention will be described with reference to the drawings.

In the figure, reference numeral 1 denotes an analysis cell having a load cell 2 at the base and opening upward, and is attached to the piston rod of the lifting cylinder St.

This vertical drive cylinder S, is attached to the piston rod of a fixed horizontal drive cylinder S2, and by driving both cylinders S, S2, the analysis cell 1 is moved to the fixed position for analysis shown by the solid line and the sample shown by the phantom line. It is set up so that it can be moved to and from the collection location. Ls is a sample supply pipe derived from the soap manufacturing process.

Corresponding to the analysis cell 1 in the fixed position for analysis, an indicator solution tank T8, a hydrochloric acid solution tank T2, a solvent tank T3,
Injection piping L led out from each cleaning liquid tank T4
, ~L4 are arranged, and a pH electrode 3, a liquid level electrode 4, and a stirrer 5 are arranged so as to protrude into the analysis cell 1. Inject pipe for indicator solution,
An indicator solution dispenser 6 is installed in , and a titration billet 7 is installed in the hydrochloric acid solution injection pipe 2 .

L5 is a liquid outlet tube opened at the inner bottom of the analysis cell 1 in the fixed position for analysis, and is for absorption analysis passing through the photocell 8.
Piping■71. It is directly connected to the discharge pipe LR through a branch part between the discharge pipe L7 and the discharge pipe L7.

■, ~■8 are solenoid valves installed in each pipe, P is a solvent pump, P2 is a thickness ratio pump, and these solenoid valves V, -V
Opening/closing of II and driving/stopping of pump PP2 are automatically performed by a control device (not shown). 9 is an optical isolake for measuring absorbance; 10 is a microcomputer-based arithmetic unit; 1] is a CRT display;
2 is a printer.

Measurement of free alkali using the automatic analyzer having the above configuration is performed as follows.

First, the vertical drive cylinder S is lowered by the air compressor, and the horizontal drive cylinder S2 is activated to horizontally move the analysis cell 1 to the sample collection position. Here, the sample collection solenoid valve 1 is opened to a set weight to collect the soap solution into the analysis cell 1, and then this solenoid valve VI is closed and the weight of the sample is accurately measured using the load cell 2.

Next, the analysis cell 1 is moved horizontally by the horizontal drive cylinder 82, and further raised by the vertical drive cylinder St to a position where the analysis cell accessory device is inserted. Here, solenoid valve V
2, and insert the indicator solution tank T into the indicator solution dispenser 6.
Fill the solution inside, close the solenoid valve V2, and then close the solenoid valve V3.
is opened, a certain amount of indicator solution is injected up to the level E2 of the level electrode 4 in the analysis cell 1, and stirred for a certain period of time by the stirrer 5 to develop color.

Next, the solenoid valve v4 is opened, and the coloring liquid is fed into the photocell 8 for a certain period of time using the extraction pump P2. The extraction pump P2 is stopped, the solenoid valve v4 is closed, and the mixture is left for a certain period of time to eliminate the influence of air bubbles. The absorbance of the coloring solution is determined by the optical isolator 9.
The content of free alkali is calculated by the arithmetic unit 10 based on the electrical signal of this measured value, and this is displayed on the CRT display 11 or printer 12.

The coloring liquid in the photocell 8 and the analysis cell 1 is controlled by the solenoid valve ■4.
is opened and discharged by the discharge pump P2.

In addition, to clean these cells, open the solenoid valve V, introduce the cleaning liquid up to the level E of the level electrode 4, stir it with the stirrer 5, and clean it. It is discharged via. Repeat this operation 2 to 3 times.

Further, the measurement of pure soap content using the automatic analyzer having the above configuration is performed as follows.

The above-mentioned washed analysis cell 1 is lowered by the vertical drive cylinder S, and then horizontally moved to the sample collection position by the horizontal drive cylinder S2, and the solenoid valve V is opened to a set weight to pour soap solution into the analysis cell 1. Collect. Solenoid valve V,
, and accurately measure the weight of the sample using load cell 2.

Next, the analysis cell 1 is moved horizontally by the action of the horizontal drive cylinder 82, and further raised to the fixed position where the analytical accessories 3 to 5 are placed by the vertical drive cylinder S, and then the analysis cell 1 is moved horizontally by the action of the horizontal drive cylinder 82. Isopropyl alcohol is injected to the level E2 of the level electrode 4 using the solvent pump P, and stirred for a certain period of time using the stirrer 5 to dissolve the sample.

In this state, open the solenoid valve V6, fill the titration billet 7 with the solution in the hydrochloric acid solution tank 2, close the solenoid valve 6, then open the solenoid valve v7, and add the soap solution in the analysis cell with the hydrochloric acid solution. Titrate. The neutralization point is detected using pH electrode 3.
The titration value is converted into the content of pure soap by the arithmetic unit W10, and this is displayed on the CRT display 11 or printer 12.

The waste liquid in the analysis cell 1 is discharged by opening the solenoid valve VB and using the extraction pump P2. To clean analysis cell 1, use solenoid valve ■5
is opened to introduce the cleaning liquid to the level E1 of the level electrode 4, stirred by the stirrer 5 for cleaning, and discharged by the discharge pump P2 via the solenoid valve V8. Repeat this operation 2 to 3 times.

Next, the results of actually measuring the content of free alkali and pure soap using the above-mentioned automatic analyzer and the results of measuring according to the JIS method are compared in Tables 1 and 2 below. show. Both measurement results were measured five times for each sample and expressed as the average value.

In addition, in the analysis using the apparatus of the present invention, a solution prepared by dissolving a mixture of phenolphthalein and cresol red in a weight ratio of 1:0.03 in a 50% by weight aqueous isopropyl alcohol solution at a concentration of 0.077% by weight was used as an indicator solution. An aqueous solution of N/]0 hydrochloric acid was used as the hydrochloric acid solution, and a 75% by weight aqueous isopropyl alcohol solution was used as the solvent.

In addition, in the absorbance measurement, a tungsten bulb was used as a light source of the photocell, and a 58Qnm interference filter was used.

Table 1 <Comparison of analytical values for free alkali> Table 2 <Comparison of analytical values for pure soap> From the results in Tables 1 and 2 above, the analytical values obtained with the apparatus of the present invention are 1. J I
The results were in good agreement with the analytical values obtained according to the S method. Furthermore, the analysis using the apparatus of the present invention was easier to operate than the manual analysis using the JIS method, and the analysis time could be significantly shortened. Note that the content of free fatty acids could be measured in the same manner as for free alkalis.

〔Effect of the invention〕

According to the automatic analyzer of the present invention, free alkali or Mi! Since ILI fatty acids are quantified by absorbance and pure soap content is determined by potentiometric titration, it is possible to automatically measure the content of these components in a short time, and the analytical operations are simpler than with conventional methods. It is extremely simple, significantly shortens analysis time, and provides outstanding effects such as improved analysis accuracy. Therefore, the automatic analyzer of the present invention has high practicality for use in process control analysis of soap manufacturing.

[Brief explanation of the drawing]

The drawing is a configuration diagram of an automatic analyzer according to an embodiment of the present invention.

Claims (1)

[Claims] (1) Add an indicator that develops color by reacting with free alkali or free fatty acids to a fixed amount of soap solution collected from the soap manufacturing process, and determine the amount of free alkali or free fatty acids in the soap solution by measuring the absorbance of the colored solution. 1. An automatic soap analyzer comprising: a quantitative mechanism for automatically measuring the amount of pure soap; and a quantitative mechanism for automatically measuring the pure soap content in the soap solution by potentiometric titration of the soap solution with a hydrochloric acid solution.