JPH0451783B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to solvents used in emission spectroscopic analysis. More specifically, the present invention provides a method for quantitatively analyzing various samples such as petroleum products and their additives containing metal elements, coal-based hydrocarbon oil, etc. by optical emission spectrometry, by diluting or dissolving the samples. Concerning the solvent used for In recent years, the development of emission spectroscopy has been remarkable, and not only has the time required for analysis been significantly shortened compared to methods such as gravimetric analysis and fluorescence It has become a preferred analytical method, especially for purposes such as process control and specification control. In this case, conventional solvents for diluting or dissolving the materials include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, alcohols such as methanol and ethanol, hexane, naphtha, petroleum ether, toluene, and xylene. Hydrocarbons, etc. are used, especially xylene,
Methyl isobutyl ketone is preferably used. However, with these conventional solvents, firstly,
The solubility of the material to be measured may be extremely poor; secondly, the flame used for measurement tends to fluctuate and lighting is poor; and thirdly, the stability of measured values is poor. It was hot. The inventors of the present invention have conducted extensive research to solve these conventional drawbacks, and have found that solvents consisting only of aromatics, such as xylene, make the flame unstable, and that solvents containing no aromatics, such as methyl isobutyl ketone, The solubility of the sample is poor, and the boiling point is approximately 100℃.
The following low-boiling point hydrocarbons or high-boiling point hydrocarbon solvents of approximately 300°C or higher may affect any or all of the following: However, the present invention was achieved by determining that the method does not give good results. Therefore, the first object of the present invention is to provide a solvent for emission spectrometry that has good solubility for a sample to be measured. Furthermore, a second object of the present invention is to provide a solvent for emission spectrometry that has good lighting properties, less flame fluctuation, and can improve the stability of measured values. That is, the present invention provides a solvent made of petroleum hydrocarbon for diluting or dissolving a sample in emission spectroscopic analysis, the composition of which is 15 to 50% by weight of aromatic components, 40 to 80% by weight of paraffin components, and 65% by weight of paraffin components. It consists of naphthenic components of less than % by weight, and the boiling point range of the solvent is
This is a solvent for emission spectroscopic analysis, characterized by a temperature of 150 to 200°C. Examples of aromatic hydrocarbons in the present invention include ordinary aromatic hydrocarbons having 8 to 11 carbon atoms, such as xylene, ethylbenzene, cumene, hemimelithene, propylbenzene, t-butylbenzene, n-butylbenzene, naphthalene, and pentamethylbenzene. Although hydrocarbons can be used, aromatic hydrocarbons having 9 and 10 carbon atoms are particularly preferred from the viewpoint of flame fluctuation and lighting performance. Next, as the paraffin component in the present invention, paraffin having 9 to 16 carbon atoms that may have a side chain, such as n-nonane and n-decane, can be used. Examples of the naphthene component include cyclopentane and cyclohexane having an alkyl group as a side chain. In this case, usually 1 to 3 cyclopentane and/or cyclohexane are bonded in one compound, but 3 or more cyclopentane and/or cyclohexane may be bonded. In addition, the group bonded to the side chain may be an alkyl group having 1 to 10 carbon atoms, and the number of these groups is usually 6 or less, but even if there are no alkyl groups in the side chain, the main Can be used for inventions. The most important factor in achieving sufficient performance as a solvent for emission spectrometry by mixing these aromatic components, paraffin components, and naphthenic components is:
This is the proportion of aromatic components. If the aromatic component is less than about 15% by weight, the dissolution performance of the sample will be poor, while if it is more than about 50% by weight, the flame of the torch during analysis will become unstable, which is undesirable. Therefore, the aromatic component is preferably about 15 to 50% by weight, especially about 15 to 35% by weight.
Weight percent is preferred. On the other hand, in optical emission spectrometry, it is generally necessary to enhance the combustion characteristics of the torch flame, and for this purpose, it is preferable that the sample solvent be rich in paraffin components. Therefore, considering the dissolution performance of the sample, the amount of paraffin component should be approximately 40~
It is 80% by weight. Also, if the viscosity of the sample is high,
It is advantageous to use paraffin with a low boiling point, such as n-nonane or n-decane, from the viewpoint of the viscosity of the sample solution. The naphthene component in the present invention has a sample dissolving performance between that of the paraffin component and the aromatic component, and can also contribute to reducing the fluctuation of the torch flame. Therefore, it is useful as a regulating solvent to exhibit desired performance, and the amount corresponds to the balance of the aromatic components and paraffin components, that is, 0 to 65% by weight. The boiling point range of the solvent adjusted as above is approximately 150~
The temperature is 200°C, and in either case, it is a good solvent for emission spectroscopic analysis. Therefore, as long as the boiling point range of the solvent is within the above-mentioned temperature range, it is acceptable for each component to contain some impurity, as long as it does not become a major cause of analytical error. However, low boiling point solvents below about 150℃
It may impair the illumination of the torch flame during analysis, or
The presence of high boiling point solvents of 200°C or higher causes a drop in the speed of sample suction into the atomizer, reducing the accuracy of immediate determination, so it is necessary to remove impurities that cause these problems, and to remove other impurities during analysis. It goes without saying that it does not contain impurities such as metal compounds that may cause errors. The flash point is approximately 30 for safety reasons during storage, etc.
-70°C, preferably about 40-60°C. Incidentally, the specific gravity of this solvent is 0.70 to 0.85, and the aniline point is approximately 40 to 70.
It is ℃. The solvent of the present invention can be easily obtained by mixing the respective hydrocarbon components as described above, but in order to obtain it in large quantities, crude oil must be distilled under atmospheric pressure to
The petroleum fraction at 200℃ is extracted and, if necessary, treated in a hydrodesulfurization equipment under certain conditions to remove impurities such as sulfur compounds, nitrogen compounds, olefin compounds, or metal compounds such as iron. You can take the following method. Petroleum fractions in crude oil with a boiling point range of approximately 150 to 200℃ contain sodium, iron, and
Not only does it contain metal compounds such as lead, but it also contains impurities such as sulfur compounds and nitrogen compounds that cause bad odors, and olfin, which polymerizes to form a gummy substance and deteriorates its performance as a solvent. In some cases, it is necessary to perform treatment using a hydrodesulfurization apparatus using a known method. For hydrodesulfurization, for example, active metals such as Co, Mo, and Ni are placed in a reactor filled with a catalyst supported on a carrier such as alumina, silica, or silica-alumina.
There is a method of passing raw distillate oil. In this case, the treatment conditions include a reaction temperature of approximately 250°C.
~350°C, the reaction pressure is set at approximately 5-50 Kg/cm ² , and the space velocity of the raw oil is approximately 0.5-10 V/H/V (V/H/V represents the oil passing capacity per volume of catalyst), preferably. is approximately 1 to 5 V/H/V, and hydrogen-containing gas is passed through at a flow rate of approximately 5 to 200 m ³ /K1 (converted to standard conditions), preferably approximately 20 to 80 m ³ /K1 (converted to standard conditions). For example, it is easy to remove impurities in petroleum fractions while preventing hydrogenation of aromatic components, and to reduce the sulfur content in the product to 0.01% by weight or less. As another method for producing a large amount of the solvent of the present invention, it is also possible to employ a method of hydrocracking a gas oil fraction or distillation residue having a boiling point of about 300° C. or higher. Hydrogenolysis is carried out at a reaction temperature of approximately 330 to 430°C, approximately 70°C to It is carried out by passing the feedstock oil through a reactor under pressure conditions of 300 Kg/cm ² . This method requires a distillation means for removing hydrocarbons having a boiling point of about 150 to 200°C from the reaction product. If the aromatic hydrocarbon component after treatment is less than about 5% by weight, it may be adjusted by adding other aromatic compounds. A sample solution using the solvent of the present invention can be prepared by diluting or dissolving the sample in the same manner as in the known case using a solvent such as xylene. Therefore, in addition to petroleum products and their additives, coal-based hydrocarbon oil, etc., the solvent of the present invention can be used for all samples that are generally dissolved in petroleum-based hydrocarbons, allowing better analysis than ever before. You can get results. The amount of solvent used is about 10 to 50 parts by volume when the content of the element to be measured in the sample is about ppm, and about 50 to 250 parts by volume when it is about %. Samples include high-boiling point petroleum hydrocarbons such as light oil, heavy oil, lubricating oil, atmospheric residual oil, vacuum residual oil, crude oil, waste oil sludge, and grease, and high-boiling point coal hydrocarbons such as coal dry distillation oil and coal liquefaction product oil. etc., if
In order to have adequate wicking properties in the analyzer's nebulizer, the amount of the solvent of the present invention must be adjusted to give the sample solution a viscosity of about 5 to 500 centistokes at room temperature. Since the solvent of the present invention has remarkable sample-dissolving power, it is possible to prepare a sample solution in a shorter time than known solvents.
This is particularly effective when the sample is a relatively viscous high-boiling hydrocarbon, an additive thereof, or a composition thereof. Conventional additives include phosphates, sulfonates, phenates, naphthenates, and sulfates of Ba, Ca, Mg, etc., dialkyldithiophosphates, dialkyldithiocarbamates, nitrates, and sulfates of Zn, and butylene polymers.
There are salts of P ₂ S ₅ reactants. Since the solvent of the present invention has good sample solubility, it is possible to widen the range of measurement samples more than conventionally.
In addition to S etc., B, Ni, V, Ag, AI, Cr,
It is also extremely easy to spectroscopically quantify samples containing elements such as Cu, Fe, Mn, Mo, Pb, Ti, Si, Na, and As. Furthermore, since the use of the solvent of the present invention brings about a large viscosity reduction effect on the sample, the present invention is particularly suitable for plasma emission spectrometry, which is said to be more susceptible to sample viscosity than atomic absorption spectrometry. The practical value of the solvent is great. The present invention will be further explained below with reference to Examples.
The present invention is not limited thereby. Example 1 As the solvent of the present invention, S ₁ , S ₂ ,
Four types of solvents, S ₃ and S ₄ , and a fifth solvent, S ₅ , obtained from crude oil were prepared by the following steps.

[Table] Specific gravity 0.8067, sulfur content 0.07% by weight, pour point -32
°C, aromatic component 27.1% by weight (in the 160-250 °C fraction)
25,000 barrels of Middle Eastern crude oil was introduced into the atmospheric distillation column. Distillation column at 350℃, 1.3Kg/cm ² (Flush zone)
The plant was operated at 7,000 barrels of middle distillate. Next, this fraction is introduced into the hydrodesulfurization equipment.
Hydrodesulfurization treatment was carried out under the conditions of 270°C and 13 kg/cm ² . Hydrogen-containing gas is 30m ³ /K1 (75 mol% hydrogen,
Solvent S ₅ in Table 2 was obtained.

[Table] However, the values of each component were determined from measurements of specific gravity, refractive index, viscosity, etc. Next, specific gravity (15/4℃) 0.8983, viscosity 105.9 centistokes (40℃), 11.5 centistokes (100℃), hue (ASTM standard) 4.0, flash point 254
About 1 gram of a lubricating oil composition sample at a temperature of -25 DEG C. and a pour point of -25 DEG C. was weighed to an accuracy of 0.001 gram, about 50 ml of each of the above solvents was added, and the sample was diluted and shaken to prepare five types of sample solutions. Each of the sample solutions prepared in this way was analyzed using a plasma emission spectrometer (ICPQ-100 model) manufactured by Shimadzu Corporation according to a conventional method, and the results shown in Table 3 were obtained.

[Table] However, each measured value is in weight%. As a result, it was confirmed that all of the plasma emission spectroscopic analysis values using the solvent of the present invention had high measurement accuracy, similar to the chemical analysis values used as the standard. Example 2

【table】

[Table] In the same manner as in Example 1 except that the solvent of the present invention was used, Zn, Ba, and P were 0.046, 0.115,
A value of 0.040% by weight was obtained. This result supports that the use of this solvent is effective for quantifying the analyte element with extremely high precision. Example 3 Using the same inventive solvent S ₅ as used in Example 1, specific gravity (15/4°C) 0.9016, viscosity 86.1 centistokes (40°C), 6.3 centistokes (100
The following results were obtained in the same manner as in Example 1, except that a lubricating oil composition sample having a color (ASTM standard) of 6.5 and a flash point of 236°C was diluted.

[Table] From this result, the solvent of the present invention has a lower
It can be seen that it is suitable for analyzing a wide variety of elements with extremely high precision. Example 4 Petroleum product additive (barium phosphate specific gravity
1.0831, viscosity 16.98 centistokes (100℃),
Barium and phosphorus were quantified in the same manner as in Example 3, except that (flash point: 198°C) was used as a sample.

[Table] Content measurements are in weight%
As shown in Table 6, in the conventional method using 25% by weight of xylene and 75% by weight of methyl isobutyl ketone, the sample hardly dissolves in this mixed solvent, resulting in analytical values that are far different from the actual contents. On the other hand, when the solvent of the present invention was used, extremely good results were obtained. Example 5 Same as Example 3 except that a heavy oil sample with specific gravity (15/4°C) 0.9712, viscosity 167 centistokes (50°C), flash point 94°C, pour point 10°C, and residual carbon 2.47% by weight was used. Nickel and vanadium were quantitatively determined.

[Table] As shown in the above table, the solvent of the present invention is also extremely suitable for the analysis of heavy oil. Example 6 The repeated measurement accuracy was measured using the solvent of the present invention used in Example 1 and a mixed solvent of 100% xylene, 2% by weight of xylene, and 75% by weight of methyl isobutyl ketone. ,Ba,P,
Measurements of each element, Mg and B, were obtained.

[Table] These results show that when the solvent of the present invention is used, the variation is small and stable measurement results can be obtained. This shows that the solvent of the present invention is extremely good, eliminating the drawbacks of conventional solvents.

Claims (1)

[Claims] 1. A solvent made of petroleum hydrocarbon for diluting or dissolving a sample in emission spectrometry, the composition of which is 15 to 50% by weight of aromatic components and 40 to 80% by weight of paraffin components. A solvent for emission spectrometry, characterized in that the solvent has a boiling point range of 150 to 200°C. 2. The solvent for emission spectroscopic analysis according to claim 1, which contains 65% by weight or less of a naphthene component as the third component.