Method of quantitative determination of methane-fullerenes in reaction mix by uv-spectroscopy method

FIELD: measurement equipment.

SUBSTANCE: invention relates to the method of quantitative determination of methane- fullerene of various level of replacement in reaction mix using UV-spectroscopy method consisting in reading of UV-spectra, plotting of calibration curves using the values of the second derivative of the spectrum, finding from them of the linear regression equations. Meanwhile for preparation of models of the studied compounds with various levels of replacement the organic solvents are used, UV-spectra are recorded in a wide interval of concentration, the linear regression equations for determination of the content of mono-replaced methane- fullerenes h=1.23×10-4c+0.01×10-5, di-replaced h=1.54×10-4c+0.20×10-5, three-replaced h=2.31×10-4c+0.30×10-5 tetra-replaced h=4.00×10-4c+0.32×10-5 then when determining methane-fullerenes with various levels of replacement in a reaction mix the analysed samples are selected from the reaction mix, UV-spectra are read, the curves are plotted on the basis of values of the second derivative of the spectrum, the respective value h is substituted in the respective linear regression equation and the concentration of methane-fullerenes in the analysed mix is calculated.

EFFECT: present invention allows to determine quantitatively the composition of complex reaction mixes of isomeric compounds consisting of two and more components in a wide range of concentration without their separation from a reaction mix with a possibility of the subsequent performing of the process before pre-planned ratio of ingredients.

2 cl, 5 tbl, 8 ex, 2 dwg

 

The invention relates to methods of quantitative determination of complex reaction mixtures, in particular methanofullerenes different degrees of substitution the method of UV spectroscopy. The invention can find application in the study of the structure fullerensoderzhashchikh macromolecular compounds, where on the basis of UV spectra is the most correctly sets out all the possible types of occurrences of C60in the polymer chain (Torx, fullerene in the primary circuit, the fullerene at the ends of the macromolecule, etc.).

Known quantitative method of finding the production of a commercial mixture of m-cresol containing o-, n-isomers of cresol, 2,4-, 2,5-, 2,6-carbonaceous carbolic acid o-ethylphenol (patent GB 760729 from 16.12.1953. The removal of the IR and UV spectra were carried out in the gas phase at 200°C, and was determined in a mixture only m-cresol with an accuracy of 0.3 to 3.0% and the error rate of the device in this method is 2%. This technique with sufficient accuracy the content is only one component in the mixture, and analyzed multiple connections it unusable. In addition, the recording of the UV spectra in the gas phase is very difficult due to the fact that not all organic matter can be transferred into the gas phase without decomposition.

The closest to the proposed invention is a method of determining in a mixture number of cefoperazone and sulbactam, was�audica in the removal of UV-spectra, graphic find first and second derivative spectra (Journal of Pharmaceuticul & Biomedicul Analysis, 1994, V. 12, No. 5. p.653-657). However, in the aforementioned method, the recording of the spectra is carried out only in water, and this greatly narrows the range of analytes that dissolve only in polar and nonpolar organic solvents. By this method it is possible to measure the concentrations of two compounds, which are procured on the production, and the authors are just preparing solutions of different concentrations.

The aim of the invention is to provide a method for the quantitative determination of complex reaction mixtures of isomeric compounds consisting of two or more components, in a wide range of concentrations without isolation from the reaction mixture with the possibility of the process to pre-planned ratios of ingredients.

This object is achieved in that the determination of complex reaction mixtures is performed in two stages. The first phase is removed and treated with UV spectra allocated methanofullerenes, distinguished by the type and number of substituents. On the basis of the second derivative UV spectra are constructed calibration graphs, which are determined by the linear regression equation. In the second phase are synthesized methanofullerene different stephenathome, removed their spectra and was found in the first stage equations of the linear regression corresponding to the type of substitution, determined by the number of substituted methanofullerenes.

The first stage is implemented as follows. Originally synthesized five complex mixtures methanofullerenes differ in the number of substituents in the core of C60. Mixture in a chromatographic column was divided into components depending on the number of substituents in the fullerene, i.e. allocated to individual connections. Then prepared solutions in organic solvents (chlorinated benzenes, chlorinated hydrocarbons, toluene, acetonitrile): randomly selected 5 or 6 concentrations in the range of 10-4-10-6mol/l (feasible it is designated intervals, as at larger than 10-4mol/l concentrations of the height of the characteristic peaks of above-scale optical absorption, and at concentrations less than 10-6mol/l, the height of the characteristic peaks is at the level of measurement error of the spectrophotometer), and each of methanofullerenes. Recorded UV spectra of all samples. Recording of the spectra was carried out at room temperature in the wavelength range from 190 to 1100 nm, but most characteristic is an interval of 250-400 nm, slit width of 2.0 nm, using a quartz cuvette with a thickness of 1 see EPA�, that the absorption spectra of the mixture methanofullerenes different degrees of substitution consists of a number of overlapping bands, the determination of the number of derivatives methanofullerenes is a difficult task. The highest selectivity of spectrophotometric analysis is achieved in the transition to the second derivative UV spectra, i.e. in the study of concentration dependencies of d2A/dλ2=f(λ). Testing different values of Δλ revealed that step-by-step coefficient Δλ=40 shows the best selectivity, high sensitivity and adequate signal-to-noise ratio for the experimental work.

The dependencies of d2A/dλ2-f(λ) (Fig.1) was measured corresponding to h1(monosubstituted methanofullerene), h2(disubstituted), etc. of the amplitude between the minimum and the maximum of d2A/dλ2at all concentrations, which are further used to construct a calibration graph (Fig.2). On the basis of a calibration curve based on the concentration of mono-, di -, etc. substituted methanofullerene from the second derivative to find the linear regression coefficients needed to calculate the molar concentrations of methanofullerenes. The parameters of linear regression for concentration dependencies of the optical density and d2A/dλ2presented in table 1.

Table 1
The parameters of linear regression for concentration dependencies of d2A/dλ2
Adductλ, nmThe linear equationRSr×103

regression
mono-359/329h=1.23×10-4c+0.01×10-50.99931.7
di-347/320h=1.54×10-4c+0.20×10-50.99933.3
three334/308h=2.31×10-4c+0.30×10-50.99970.6
Tetra-317/279h=4.00×10-4c+0.32×10-50.99761.5

The second stage is implemented with specific examples of implementation of the method of quantitative determination methanofullerenes in the reaction mixture in different solvents.

Example 1. To a solution of 0.1 g (0.14 mmol) of fullerene C60in 30 ml of toluene was added 0.069 g (0.2 mmol) CBr4, 0.033 ml (0.18 mmol) of galliavola ester of malonic acid and 0.32 ml (0.21 mmol) of diazabicyclo[4.2.0]undec-7-Jena (DBU). The reaction mixture was stirred under inert atmosphere at room temperature for 1.5 h, then was filtered, the filtrate was washed with 5% HCl solution, dried over MgSO4that was evaporated. The residue was separated separated by column chromatography on SiO2, eluent - toluene. Got 0.040 g (~32 wt.%) monosubstituted, 0.02 g (~14%) disubstituted, 0.015 g (~8%) and trisubstituted 0.01 g (~5%) tetramaster products. Spectroscopic analysis of the reaction mixture showed, with 35.2 wt.%) monosubstituted, (15,9%) disubstituted, (8,8%) and trisubstituted (6,3%) tetramaster products.

Example 2. Analogously to example 1, except that the process time is 4 hours. After the division separated by column chromatography on SiO2(toluene) received: (12 wt.%) monosubstituted, (36%) disubstituted, 0.015 g (24%) and trisubstituted (15%) tetramaster products. Spectroscopic analysis of the reaction mixture showed (14.3 wt.%) monosubstituted, (37,0%) disubstituted, (25,8%) and trisubstituted (18,2%) tetramaster products table.2). For the evaluation of the results of the quantitative analysis of mixtures methanofullerenes compared them with data HPLC (conditions chromatographic analysis: chromatographic system Shimadzu LC-20" with spectrophotometric diagnosticum detector (Japan); detection was carried out at a wavelength of 280 nm, used column Exsil Silica 250×4.6 mm, 5 μm, mobile phase was used eluent composition of hexane:toluene:isopropyl alcohol=97:2:1, the feed rate of the mobile phase was 1 ml/min.

Table 2
Comparison of methods for the quantitative determination of a mixture methanofullerenes in toluene
The number of deputiesExample 1 (1.5 hours)Example 2 (4 hours)
Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%
mono-32,035,2 35,212,014,414,3
di-14,015,815,936,037,137,0
three8,08,88,824,025,825,8
Tetra-5,06,46,315,018,418,2

Example 3. Analogously to example 1, but the solvent used chloroform (chlorinated hydrocarbon), the process time is 1.5 hours. The results of the analysis of the reaction mixture are presented in table.3.

Example 4. Analogously to example 1, but the solvent used chloroform (chlorinated hydrocarbon), the process time is 4 hours. The results of the analysis of the reaction mixture are presented in table.3.

Table 3
Comparison of methods for the quantitative determination of a mixture IU�anapolitanos in chloroform
NumberExample 3 (1.5 hours)Example 4 (4 hours)

ViceColumn chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%
mono-34,035,835,916,016,516,7
di-10,013,213,240,1of 40.8of 40.8
three8,59,09,026,027,5to 27.4

Example 5. Analogously to example 1, but the solvent used acetonitrile, the process time is 1.5 hours. The results of the analysis of the reaction of CME�and presented in table.4.

Example 6. Analogously to example 1, but the solvent used acetonitrile, the process time is 4 hours. The results of the analysis of the reaction mixture are presented in table.4.

Table 4
Comparison of methods for the quantitative determination of a mixture methanofullerenes in acetonitrile
The number of deputiesExample 5 (1.5 hours)Example 6 (4 hours)
Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%
mono-32,935,034,915,7of 17.817,9
di-13,414,914,939,941,241,2

Example 7. Analogously to example 1, but the solvent used o-dichlorobenzene (chlorinated benzene) (chlorinated benzene), the process time is 1.5 hours. The results of the analysis of the reaction mixture are presented in table.5.

Example 8. Analogously to example 1, but the solvent used o-dichlorobenzene (chlorinated benzene), the process time is 4 hours. The results of the analysis of the reaction mixture are presented in table.5.

Table 5
Comparison of methods for the quantitative determination of a mixture methanofullerenes in o-dichlorobenzene
The number of deputiesExample 7 (1.5 hours)Example 8 (4 hours)
Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%Column chromatography on SiO2wt.%HPLC, wt.%UV-spectroscopy, wt.%
mono-at 34.336,536,715,917,1
di-14,115,115,2the 38.639,239,1

The accuracy of quantitative measurement of various methanofullerenes in mixture using UV-spectroscopy and HPLC are well correlated and comparable among them. However, in the case of HPLC selection mixture allentow to separate methanofullerenes very time consuming and for the implementation of the method requires very expensive equipment.

Thus, quantification of various methanofullerenes in complex mixtures by UV-spectroscopy with high accuracy and in a short time to ascertain the concentration of two or more components without interrupting the process. With the use of UV spectroscopy can be: a) to investigate the reaction kinetics of education methanofullerene based on the C60b) to bring the reaction to the planned concentration of the desired isomer in the reaction mixture, i.e. in General to control the process.

1. A method for quantifying methanofullerenes different degrees of substitution in the reaction mixture by UV-spectroscopy, which consists in the removal of UV-spectra, the construction of calibration graphs based on the values of W�Roy derivative spectrum finding them linear regression equations, characterized in that for the preparation of samples of the investigated compounds of various degrees of substitution of organic solvents are used, the recording of the UV spectra is produced in a wide range of concentrations, the linear regression equation for the determination of monosubstituted methanofullerenes h=1,23×10-4c+0,01×10-5, disubstituted h=1,54×10-4c+0,20×10-5, trisubstituted h=2,31×10-4c+0,30×10-5, terazosina h=4,00×10-4c+0,32×10-5then when you define methanofullerenes different degrees of substitution in the reaction mixture is sampled analyzed samples from the reaction mixture, removal of the UV spectra of the plot is based on the values of the second derivative spectrum, the substitution of the appropriate value of h in the corresponding linear regression equation and calculating the concentration methanofullerenes in the analyzed mixture.

2. A method for quantifying methanofullerenes different degrees of substitution in the reaction mixture by UV spectroscopy according to claim 1, characterized in that as the organic solvent used chlorinated benzenes, chlorinated hydrocarbons, toluene, acetonitrile, recording UV spectra is performed in a concentration range from 10-4-10-6mol/l, wherein the designated number�number of components in a mixture of two or more.



 

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