JP2588083B2 - Method for measuring phenol content in oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for simply measuring phenol content in oil.

[0002]

2. Description of the Related Art The measurement of phenol content in oil has been conventionally performed by the following method with reference to JIS K0102 and other various documents. First, a NaOH solution is added to the oil to be measured and shaken to extract phenol into the aqueous layer. Next, the aqueous layer was taken out, neutralized with phosphoric acid or sulfuric acid, and adjusted to pH 1 with an NH ₄ Cl · NH ₄ OH solution.
Adjust to 0, add 4-aminoantipyrine solution and potassium ferricyanide solution and react with phenol to produce antipyrine dye. Thereafter, the absorbance at a specific wavelength of the aqueous layer in which the antipyrine dye has been formed is measured using a spectrophotometer. The measurement results are compared with a calibration curve to quantify the phenol content.

[0003]

However, the above-mentioned conventional method for measuring phenol content in oil has the following problems. (1) The measurement of the absorbance by the spectrophotometer, as well as the comparison between the measurement result and the calibration curve are extremely complicated, and the measurement time is considerably long. Some knowledge and skill are required in comparison with lines. (2) When a person with little knowledge or an unskilled person performs the measurement, the measurement time becomes longer, sometimes an accurate quantitative result may not be obtained, and the measurement operation must be repeated. It is. (3) In addition, the use of a spectrophotometer and a calibration curve is essential, and measurement is impossible in a site where these do not exist. (4) In addition, it is necessary to adjust the pH of the solution before generating the antipyrine dye.

[0004] Under the above circumstances, the present invention provides:
An object of the present invention is to propose a method capable of easily and quickly measuring the phenol content in oil at any location without using instruments such as a spectrophotometer.

[0005]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that the color of the antipyrine dye formed in each of the solutions containing phenol at various concentrations is determined in advance. Liquids having the same color (standard color) (that is, colorimetric standard liquids) are prepared, and the colors of these liquids and the oil to be measured are treated in substantially the same manner as the above-mentioned conventional measuring method. By comparing the color of the liquid in which the antipyrine dye was formed, the phenol content in the oil to be measured can be easily and quantitatively determined with high accuracy, and the extraction of phenol in the oil to be measured is described above. Conventional N
Instead of an aOH solution , an NH ₄ Cl.NH ₄ OH solution (p
H buffer), it is possible to immediately generate an antipyrine dye without pH adjustment after the extraction (in the case of extraction with a conventional NaOH solution ,
PH adjustment is required as described above), and the present invention has been developed.

That is, according to the present invention, there is provided a method for measuring phenol content in oil, wherein the phenol content in the oil is determined by NH ₄
Cl · NH 4 _OH solution was used to extract the aqueous layer, and the measurement sample to generate antipyrine dye to create a reaction between phenol and 4-amino-antipyrine in the aqueous layer, the following corresponding to the known phenol concentration Any of (1) to (4)
The gist is a method for measuring phenol content in oil, characterized in that the colorimetric standard solution is colorimetrically determined with the naked eye. (1) Aqueous solution of potassium dichromate (2) Aqueous solution of Hazencolor stock solution (3) Mixed aqueous solution of Hazencolor stock solution and cobalt chloride (4) Aqueous cobalt chloride solution

[0007] In the measurement method of the present invention, first, phenol in oil is extracted into an aqueous layer, and phenol in the aqueous layer and 4- amido are extracted.
Roh is reacted with antipyrine preparing a measurement sample to generate antipyrine dye. The extraction of the phenol in the oil into the aqueous layer can also be performed using a NaOH solution as in the case of the above-described conventional measurement method. However, in this case, it is necessary to adjust the pH of the aqueous layer after extracting phenol in the oil into the aqueous layer, as described above. Therefore, in the present invention, _NH 4 Cl · instead of NaOH solution
The NH ₄ OH solution is added to the oil to be measured and shaken,
The phenol in the oil is extracted into the aqueous layer. The aqueous layer is collected, and without adjusting the pH, a solution of 4- aminoantipyrine is added and reacted with phenol in the aqueous layer to generate an antipyrine dye, which is used as a sample for measurement. This reaction can be shown as follows.

[0008]

Embedded image

Next, the hue of the measurement sample prepared as described above and the hue of the colorimetric standard solution corresponding to a known phenol concentration are compared with the naked eye. As this colorimetric standard solution,
Although any type may be used, in the present invention, the following four colorimetric standard solutions are used .

(1) Potassium dichromate aqueous solution (hereinafter, referred to as
Colorimetric standard solution (1)), (2) aqueous solution of Hazencolor stock solution (hereinafter, referred to as colorimetric standard solution (2)), (3) mixed aqueous solution of Hazencolor stock solution and cobalt chloride (hereinafter, ratio Color standard solution 3), (4) aqueous solution of cobalt chloride (hereinafter referred to as colorimetric standard solution (4)), and these colorimetric standard solutions (1) to (4) contain phenol as described above. This refers to a liquid that exhibits the same color (standard color) as the color when an antipyrine dye is formed in each of the liquids containing various concentrations. Hereinafter, these colorimetric standard liquids (1) to (4) will be sequentially described.

The colorimetric standard solution (1) is potassium bichromate.
It is a liquid in which K ₂ Cr ₂ O ₇ is dissolved in water at a predetermined concentration to give a color equivalent to the color of an antipyrine dye produced with phenol at a predetermined concentration. Preferably, JIS
K ₂ Cr ₂ O ₇ special grade reagent specified in K8517 0.0
An aqueous solution prepared by dissolving 03 g in water so as to have a volume of 1000 ml can be used. It is important that the absorbance of the aqueous potassium bichromate solution be within the range of 0.005 ± 0.002 at a wavelength of 450 nm, using water as a control solution. The reason can be explained as follows.

That is, the color of the antipyrine dye produced by treating the oil to be measured is such that phenol is 0 ppm
As the concentration becomes higher, the color changes from blue to yellow and further to reddish brown. Light having a wavelength of 450 nm absorbs the color of the blue system best, and light of the wavelength of 510 nm absorbs the color of the yellow or reddish-brown system best. The colorimetric standard solution (1) mainly has a phenol content of 0%.
In order to measure an oil having a very low concentration of around ppm, the absorbance of the aqueous solution of potassium bichromate constituting the standard solution was determined to be 0.005 ± 0.
This is because if it is within the range of 002, the phenol content in the oil can be measured with extremely high accuracy.

The colorimetric standard solution (2) is composed of an aqueous solution of a Hazen color undiluted solution. The Hazen color undiluted solution is dissolved in water at a predetermined concentration, and a color equivalent to the color of an antipyrine dye produced by phenol at a predetermined concentration. Is a liquid having The colorimetric standard solution (2) is mainly used for measuring the phenol content of an oil having a phenol content in the range of about 0.05 ppm to 0.1 ppm.

The Hazen color undiluted solution refers to an aqueous solution containing potassium chloroplatinate, cobalt chloride, and hydrochloric acid, and is generally used to measure the hue (Hazen color) of a liquid. The Hazen color undiluted solution used for the colorimetric standard solution (2) uses potassium chloroplatinate potassium K ₂ PtCl ₆ as potassium chloroplatinate, CoCl ₂ as cobalt chloride, and converts these salts into hydrochloric acid. And dissolved well in water. Preferably, 1.245 g of reagent grade potassium dichloroplatinate specified in JIS K8163 and JIS K8129
1.000 g of reagent-grade CoCl ₂ specified in
Concentrated hydrochloric acid of special grade of reagent specified in ISK8180 100m
can be used in a ratio such that 1 is dissolved in water to make 1000 ml. It is important that the absorbance of this Hazencolor stock solution is within the range shown in Table 1. The reason can be explained as follows.

As described above, the Hazen color undiluted solution is
Phenol content is about 0.05ppm-0.1pp
m, a colorimetric standard solution for measuring oil in the concentration range of m, and a colorimetric standard solution for measuring oil mainly having a phenol content of about 0.1 ppm as described later. (3), wherein the phenol content in the light having the wavelength shown in Table 1 is within the range shown in Table 1 when the phenol content is as low as about 0.05 ppm to about 0.1 ppm. This is because it is important for measuring the phenol content in oil at various concentrations up to the medium concentration with high accuracy.

[0016]

[Table 1]

The colorimetric standard solution (3) is an aqueous solution containing the above-mentioned Hazencolor stock solution and cobalt chloride. The Hazencolor stock solution and cobalt chloride are dissolved in water at predetermined concentrations, respectively, and the phenol having a predetermined concentration is dissolved. Is a liquid having a color equivalent to the color of the antipyrine dye produced in the above. The colorimetric standard solution (3) mainly has a phenol content of about 0.1%.
It is used when measuring the phenol content of oil at a concentration near ppm.

As the above-mentioned cobalt chloride, an aqueous solution can be preferably used, and more preferably, an aqueous solution in which CoCl ₂ is dissolved in dilute hydrochloric acid for stabilizing a colorimetric standard solution can be used. More preferably, C defined in JIS K8129 is used.
An aqueous solution prepared by dissolving 5.00 g of oCl ₂ special-grade reagent in 3N hydrochloric acid to a volume of 100 ml can be used. The absorbance of this aqueous cobalt chloride solution is 51
At 0 nm, 1.215 ± 0.005 with water as control
It is important to be within the range. The reason is that the cobalt chloride aqueous solution is used not only as the colorimetric standard solution (3) but also as a colorimetric standard solution (4) described later.
Since these colorimetric standard solutions (3) and (4) mainly measure oil containing a phenol component at a high concentration of 0.1 ppm or more, the absorbance of the aqueous cobalt chloride solution is measured at the above-mentioned wavelength. This is because if it is within the range of 1.215 ± 0.005 at 510 nm, the phenol content in oil can be measured with extremely high accuracy.

The colorimetric standard solution (3) is prepared, for example, by adding the aqueous solution of cobalt chloride prepared as described above to 0.5 to 32% by volume (as cobalt chloride) based on the total amount of the colorimetric standard solution (3). Is preferably added to the above-mentioned Hazen color undiluted solution at a ratio such that it becomes about 0.025 to 1.6 wt%) to give a color equivalent to that of the antipyrine dye produced at a predetermined phenol concentration. Can be used.

The colorimetric standard solution (4) is composed of an aqueous solution of cobalt chloride. Cobalt chloride is dissolved in water at a predetermined concentration to give a color equivalent to the color of an antipyrine dye produced with phenol at a predetermined concentration. Liquid. The colorimetric standard solution (4) is mainly used for measuring the phenol content of a high-concentration oil having a phenol content of 0.1 ppm or more.
As the aqueous cobalt chloride solution, for example, the aqueous cobalt chloride solution used for the above-mentioned colorimetric standard solution (3) can be used as it is.

The above colorimetric standard solutions (1) to (4)
Can be stored for a long period of time (for example, about one year) in a cool and dark place in a tightly closed state. Therefore, if a large amount of phenol corresponding to various concentrations is prepared in advance, Immediately, the phenol content in the oil can be measured.

Oils which can be measured by the measuring method of the present invention using the colorimetric standard solutions (1) to (4) described above in detail include crude oils, heavy oils, lubricating oils and the like as long as they contain phenol. Other than the above, any one may be used, and specific examples include naphtha, kerosene, light oil, petrochemicals, and solvents. In addition, in the case of oil containing only a very small amount of phenol, it is difficult to perform measurement with high accuracy, and conversely, even if the oil contains a large amount, the operation such as dilution is complicated, Preferably, the oil is contained in the range of about 50 ppb to about 10 ppm. Of course, when phenol is 0, it can be easily determined.

In the case where colorimetric measurement is carried out between the colorimetric standard solution (1) to the colorimetric standard solution (1) to the colorimetric standard solution (1), which is obtained by reacting the aqueous layer with phenol to form an antipyrine dye by the measuring method of the present invention When the concentration of phenol is, for example, 0 ppm, 0.0
Colorimetric standard solutions (1) to (4) corresponding to 5 ppm, 0.1 ppm, 0.5 ppm,... Are prepared in advance. At this time, for example, when the concentration of phenol is about 0 pp
Colorimetric standard solution (1) in the range of m to 0.05 ppm
When the amount is in the range of about 0.05 ppm to 0.1 ppm, it is prepared as a colorimetric standard solution (2).
In the case of around pm, it is prepared as a colorimetric standard solution (3), and when it is more than about 0.1 ppm, it is prepared as a colorimetric standard solution (4) (for convenience of explanation, the phenol concentration is 0 ppm,
0.05 ppm, 0.1 ppm, 0.15 ppm, 0.
Colorimetric standard solution corresponding to 2 ppm ...
D, ho ...). Then, the hue of the measurement sample and the colorimetric standard solutions A, B, C, D, E,.
.. Are compared with the naked eye. If a colorimetric standard solution having the hue closest to the hue of the measurement sample is selected, the phenol concentration corresponding to this colorimetric standard solution is referred to as the phenol concentration of the measurement sample. Therefore, in the measurement method of the present invention, a colorimetric standard solution having a large number of phenol concentrations in advance, for example, every 0.05 ppm or 0.01
It is preferable to prepare a sample whose concentration is changed at fine intervals, such as every ppm, in order to increase the measurement accuracy. In the measurement method of the present invention, when measuring a sample containing only a very small amount of phenol, for example, near the lower limit (50 ppb) described above, the colorimetric method is used, for example, a colorimetric standard solution and a sample for measurement. If the colorimetric tubes containing the color tubes are placed in a dark place and light is projected from below these colorimetric tubes,
Even with such a very low concentration of phenol, measurement can be performed with considerably high accuracy.

[0024]

In the measurement method of the present invention, the preparation of the sample for measurement is performed by :
The N H 4 _Cl · NH 4 _OH solution phenol in oil with was extracted into the aqueous layer, carried out by generating the antipyrine dye added a solution of 4-amino-antipyrine to the aqueous layer. _NH This 4 C
In the case of extracting phenol in oil into an aqueous layer with l · NH ₄ OH solution, a conventional method for measuring phenol content in oil is used.
Compared with the method up to the formation of antipyrine dye
Therefore, it is not necessary to adjust the pH of the aqueous layer from which phenol in the oil is extracted, and the operation is simplified. The measurement sample was only colorimetric macroscopically above colorimetric standard solution (1) to (4), the measurement sample, the concentration of phenol in the oil is in its turn an original measured, It can be measured very easily. At this time, if a large number of colorimetric standard solutions are prepared for phenols having various concentrations, quantification with extremely high precision can be performed.

The above colorimetric standard solutions (1) to (4) include:
An antipyrine dye is formed in a solution containing phenol at various concentrations to give a color equivalent to the color developed.
For example, the colorimetric standard solution (1) has the same color as the color obtained by forming an antipyrine dye in a solution containing phenol at an extremely low concentration of about 0 ppm, and the colorimetric standard solution (2) is slightly more. The color and colorimetric standard solution (3), which is equivalent to the color produced by forming an antipyrine dye in a solution containing phenol at a concentration of about 0.05 ppm to 0.1 ppm, is much larger.
The colorimetric standard solution (4) has the same color as the color produced by forming an antipyrine dye in a solution containing phenol at a concentration of about 1 ppm, and the antipyrine dye is used in a solution containing phenol at a concentration of 0.1 ppm or more. A color equivalent to the color generated and colored is presented.

At this time, if each of the colorimetric standard liquids (1) to (4) is assumed to have a large number of colors corresponding to a large number of phenol concentrations (for example, 0 as the colorimetric standard liquid (1)) .01 ppm, 0.02 ppm... Are prepared in a large number, and 0.05 ppm, 0.06 ppm, 0.07 ppm.
.. Were prepared, and 0.11 ppm, 0.12 ppm... Were prepared as colorimetric standard solutions (4).
If a large number of samples corresponding to each of the above are prepared), the original measurement target used in preparing the measurement sample in the measurement sample containing phenol at an unknown concentration The concentration of phenol in oil can be easily and accurately determined by visual colorimetry between the colorimetric standard solution and the measurement sample.

[0027]

EXAMPLES Specific examples of the colorimetric standard solution and the measuring method of the present invention will be described. Preparation stage: (1) Preparation of measurement sample reagent: ₍₁₎ Preparation of _NH 4 Cl · NH 4 OH solution; JISK8
Ammonium chloride reagent special grade 11g specified in 116
Was dissolved in 110 ml of an aqueous ammonia reagent specified in JIS K8085, and 20 l of water was added.
This solution was sealed and stored in a cool and dark place. (2) Preparation of potassium ferricyanide solution (2 w / v%): 2.0 g of potassium ferricyanide reagent specified in JIS K8802 was dissolved in water to make 100 ml. This solution was prepared every two weeks. After preparation, 2
Those that turned dark red, even within weeks, were not used. (3) Preparation of 4-aminoantipyrine solution (2 w / v%); 2.0 g of 4-aminoantipyrine reagent specified in JIS K8048 was dissolved in water to make 100 ml. This solution was prepared every two weeks.

[2] Preparation of reagent for colorimetric standard solution: (1) Preparation of aqueous cobalt chloride solution: 5.00 g of a special grade of cobalt chloride reagent specified in JIS K8129 was dissolved in 3N hydrochloric acid to make 100 ml. This aqueous solution has an absorbance of 1.2 at 510 nm when measured using a photoelectric spectrophotometer (absorption cell 10 mm) with water as a control solution.
The range was 15 ± 0.005. (2) Preparation of aqueous solution of potassium bichromate; JISK85
Special grade of potassium dichromate reagent specified in 17 0.00
3 g was dissolved in water to make 1000 ml. This aqueous solution had an absorbance of 0.005 ± 0.0 at 450 nm as measured in the same manner as the above cobalt chloride aqueous solution.
02. (3) Preparation of Hazencolor stock solution; potassium chloroplatinate reagent special grade 1.245 specified in JIS K8163
g, cobalt chloride reagent grade 1.000 g specified in JIS K8129, and hydrochloric acid reagent grade 100 ml specified in JIS K8180 are dissolved in water to 1000 ml.
And The absorbance of this stock solution was measured in the same manner as in the above-mentioned aqueous cobalt chloride solution, and was within the range of Table 1 described above. (4) Preparation of hydrochloric acid: 6 ml of 6N hydrochloric acid was prepared by dissolving 100 ml of a hydrochloric acid reagent specified in JIS K8180 in water to 200 ml. In addition, the above hydrochloric acid reagent special grade 50m
was dissolved in water to make 200 ml to prepare 3N hydrochloric acid.

[0029] [3] colorimetric standard solution: A mixture of the above Symbol [2] the reagent of (1) to (4), were blended in proportions shown in Tables 2 3, colorimetric standard solution (1) To (4) (five kinds of colorimetric standard solutions (4) were prepared as shown in Table 3). The absorbance of these colorimetric standard solutions measured in the same manner as in the above-mentioned aqueous solution of cobalt chloride was within the range shown in Table 4. The colorimetric standard solutions (1) to (4) thus prepared were placed in a colorimetric tube having the same quality and the same diameter as specified in JIS K8004, and sealed.

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[4] Measurement of phenol content: In a 500 ml Erlenmeyer flask with a stoppered stopper, the above (1) of (1)
In taking a _NH 4 Cl · _NH 4 OH solution 100ml prepared, naphtha 100g was added and after vigorous shaking for 1 minute,
It was left still. Here, 4- (4) prepared in (3) of [1] above was used.
After adding 0.6 ml of the aminoantipyrine solution and shaking, 1 ml of the potassium ferricienide solution prepared in (2) of the above [1] was added, and the mixture was vigorously shaken again for 1 minute.
After standing for minutes, the separated aqueous layer (colored aqueous solution) was collected by filtration with a filter paper to obtain a sample for measurement. The measurement sample and the colorimetric standard solutions (1) to (4) of Tables 2 and 3 prepared in the above [3] were compared with the naked eye. As a result, it was confirmed that 0.05 ppm of phenol was mixed in 100 g of the naphtha. For reference, was measured phenol fraction in a spectrophotometer in accordance with conventional measurement method described above, the above measurement results measured by the method and the same results of the present invention using a colorimetric standard solution of the present invention Obtained.

[0034]

As described in detail above, according to the present invention,
By preparing in advance colorimetric standard solutions corresponding to phenols of various concentrations, the phenol content in oil can be measured very easily. According to the present invention,
It is not necessary to use instruments such as a spectrophotometer, and it is only necessary to compare the hue between the colorimetric standard solution and the measurement sample with the naked eye. The phenol content in oil can be measured. In particular, during the extraction of oil phenol in water layer, instead of the conventional NaOH _solution for using _NH 4 Cl · NH 4 OH, without adjusting pH after extraction, immediately generating antipyrine dye Can be performed, and the operation can be further simplified. Furthermore, according to the present invention, anyone can easily measure phenol content in oil without requiring special knowledge or skill.

Claims (1)

(57) [Claims] 1. A method for measuring a phenol content in an oil, wherein the phenol in the oil is measured using an NH ₄ Cl.NH ₄ OH solution.
A sample for measurement in which phenol in the aqueous layer is reacted with 4- aminoantipyrine to form an antipyrine dye,
The following (1) to (4) corresponding to known phenol concentrations
A method for measuring phenol content in oil, characterized in that any one of the colorimetric standard solutions is colorimetrically determined with the naked eye. (1) mixing of the aqueous potassium bichromate solution (2) aqueous solution of Hazen color solution (3) the Hazen color concentrate cobalt chloride
Aqueous solution (4) Cobalt chloride aqueous solution