JP2001318088A - Method of quantitative analysis for unstable reaction intermediate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of quantitative analysis for an unstable intermediate of which the standard substance does not exist. SOLUTION: When the factor of an atomic group is designated by f, a response from an analyzer by r, the number of unstable intermediates by M, a quantification function therefor by F(r), the number of known constituents by M, the number of samples of an analyzed reaction liquid by n, the concentration of a known constituent by c, the total sum of the concentrations of prepared constituents multiplied by the factors of the samples by C, and the number of times of analysis by m, unknown parameters of the quantification function F(r) are determined by a numerical calculation so as to minimize the value expressed by a number 1. This quantification function is used for quantification.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analysis method used for quantitative analysis of a reaction solution generated by a certain reaction.

[0002]

2. Description of the Related Art In the case of an unstable substance, a standard product for preparing a calibration curve for quantitative analysis may not be available. In such a case, it was very difficult to perform an accurate quantitative analysis.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and a method for preparing a calibration curve and performing a quantitative analysis without a standard product for preparing the calibration curve is provided. The purpose is to provide.

[0004]

When the following conditions are satisfied, it is possible to prepare a calibration curve and perform quantitative analysis by using the method provided by the present invention even if there is no standard product for preparing the calibration curve. Will be possible. 1. The atomic group balance has been clarified for the raw material components before the reaction. 2. The concentration of a known component can be determined by analyzing the reaction solution. 3. The response of the unknown component analyzer does not include the response of other substances.

When this condition is satisfied, the number of atomic groups conserved before and after the independent reaction of the unstable reaction intermediate is represented by N,
The response from the analyzer is r, the number of unstable intermediates is L, its quantification function is F (r), the titer of the atomic group is f ^{n ,} the number of other known components is M, and the atomic group of the component is M titer f ^k of, n the reaction liquid specimen number to be analyzed, C, 1 the concentration of known components c, and the sum of the titers of the product of density and atomic groups of the reaction mixture charged component of the analyte in the sample Assuming that the number of times of analysis of the sample is m, the parameter of the unknown quantitative function F (r) is calculated by a numerical calculation so that the value represented by Equation 2 for the i-th atomic group is minimized for each of 1 to N. Can be determined and quantified using this quantification function. It should be noted that the atomic group balance referred to here includes not only the whole molecule, that is, the mass balance and the group but also simple element species.

[0006]

(Equation 2)

Specifically, a case where dimethyl carbonate is synthesized from ethylene carbonate (EC) and methanol (MeOH) will be described in detail as an example. In this reaction, in addition to the target product DMC, ethylene glycol (E
G), which are known substances for which reference materials are available. In addition, methyl hydroxyethyl carbonate (MHC) and dihydroxyethyl carbonate (DHC), which are intermediates, are produced, but they are unstable and cannot be separated and purified by distillation or the like to obtain a pure standard substance. Have difficulty.

However, since the conservation law is established before and after the reaction with respect to the content and mass of the atomic groups, a quantitative function of unknown MHC or DHC can be obtained by using these relationships. In this reaction, L = 2 (MH
C and DHC), M = 4 (EC, MeOH, DMC, E
G), N = 4 (CH ₃ , C ₂ H ₄ , CO, mass).
There are also OH and mere elemental species C, H, O as atomic groups,
It is preserved before and after the reaction, but is not used because MHC and DHC are not independent of other atomic groups. The greater the number of samples and the number of analyzes, the better the accuracy of the quantification function to be obtained. In addition, it is preferable to prepare a reaction solution having a similar composition but different concentration of each component as much as possible.

[0009] The quantitative function is usually called a calibration curve.
It is simply a proportional relationship, a linear function (having an intercept), a polygonal line, and other functions, but a proportional relationship and a linear function are often used. In a proportional relation, F (r) = m · r (m: proportional constant) In a linear function, F (r) = m · r + n (m: slope,
n: intercept).

In order to obtain the parameters of this quantitative function by numerical calculation from the obtained analysis values, ordinary spreadsheet software, mathematical formula processing software and the like can be used.
The calculation program may be created in a programming language such as AN.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention makes it possible to analyze unstable intermediates, which has been difficult to analyze in the past, so that reaction analysis, process design, and the like can be efficiently performed.

[0012]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. (Example 1) Using a strongly basic anion exchange resin (Diaion PA308 manufactured by Mitsubishi Chemical Corporation), a reaction of a raw material composition in which the composition of EC / MeOH / EG was changed by 6 kinds was performed at 40 ° C for 24 hours, and 6 kinds of specimens were obtained. And analyzed by high performance liquid chromatography. One sample was analyzed twice. m = 2 and n = 6.

The analysis conditions were as follows: column: water-based GPC column (ASAHIPAK GS-310H manufactured by Asahi Kasei), eluent: water, detector: RI, sample dilution ratio 1/100, and sample injection volume 10 μl.

When the potency of an atomic group is expressed in mole, it is the number of atomic groups contained in one molecule of each component.

That is, Table 1 is obtained. (The mass and element type are also shown.)

[0016]

[Table 1]

The unit of the concentration is a mass fraction. In that case,
Since the content is 1 g of each component, the titer of the atomic group is divided by the molecular weight other than the mass, as shown in Table 2. (OH and OH not used for calculation are omitted.)

[0018]

[Table 2]

Table 3 shows the sum (C) of the product of the charged composition, the charged concentration, and the atomic group potency shown in Table 2.

[0020]

[Table 3]

The total of the product of the results of two analyzes of each of the six specimens (peak area of unknown data, ie, the response r of the analyzer), the concentration of the known component (c), and the titer of the atomic group (f ^k ) was calculated. It is shown in Table 4.

[0022]

[Table 4]

A linear function was used as the quantitative function. Thus, the unknown parameters are slopes and intercepts. Using the values in Tables 3 and 4, simultaneous for each atomic group so as to minimize the value of Equation 2 and using mathematical processing software, evenb
erg-Marquardt method to apply DHC, MH
The slope (m) and intercept (n) of C were determined. Calculation result m _MHC = 1.002E-6 n _MHC = -5.224E-4 m _DHC = 9.587E-7
n _DHC = -2.268E-4. Using this value, MHC,
The DHC concentration was calculated, the result was multiplied by the titer, and the sum was compared with the value calculated from the analysis of the known components, and the results are shown in Table 5.

[0024]

[Table 5]

The value calculated based on the concentration (F (r)) calculated from the response (r) of the analysis value using the determined parameters (m, n) and the value calculated from the known component are shown in the table. Thus, it is clear that the quantitative analysis can be performed with high accuracy by this method.

Claims (3)

[Claims] 1. A method for quantitatively analyzing an unstable reaction intermediate in which it is difficult to obtain a standard substance, wherein the number of atomic groups stored before and after an independent reaction of the unstable reaction intermediate is N, , The number of unstable intermediates is L, the quantification function is F (r), the titer of the group is f ^{n ,} the number of other known components is M, the force of the group of the component is The value is f ^k , the number of reaction solution samples to be analyzed is n, the concentration of a known component in the sample is c,
Assuming that the total sum of the product of the concentration of the components charged in the reaction solution of the sample and the titer of the atomic group is C, and the number of times of analysis of the sample is m, the value represented by Formula 1 for the i-th atomic group is 1 A parameter of an unknown quantification function F (r) is determined by numerical calculation so as to minimize each of the steps from N to N, and quantification is performed using this quantification function. . (Equation 1) 2. The method according to claim 1, wherein said unstable intermediates are methylhydroxyethyl carbonate and dihydroxyethyl carbonate, which are unstable intermediates in a transesterification reaction between ethylene carbonate and methanol. 3. The method according to claim 1, wherein said analyzer is a high performance liquid chromatograph.