Method for determining hydroxyl groups in phenol-formaldehyde resins

Abstract

This application provides a method for determining hydroxyl groups in phenolic resin, belonging to the field of materials testing technology. It includes obtaining the phenolic resin to be tested... 13 C-NMR spectra, and based on 13 The C-NMR spectrum is analyzed as follows: A signal is detected at a shift of 103 ± 2 ppm. If a signal is present, the phenolic resin being tested contains diphenols. Alternatively, the signal at shifts 165–148 ppm is integrated and recorded as A1, 148–144 ppm as A2, and 144–95 ppm as A3. The content of hydroxyl groups and / or diphenols in the phenolic resin is calculated based on A1, A2, and A3. This method determines the presence of diphenols based on signals at specific shifts, providing a relatively rapid and accurate assessment. Integrating the characteristic shift signals allows for a relatively accurate calculation of the hydroxyl and / or diphenol content in the phenolic resin.

Description

Technical Field

[0001] This application relates to the field of materials testing technology, and more specifically, to a method for determining hydroxyl groups in phenolic resin. Background Technology

[0002] Phenolic resins have a wide range of applications, and their performance is directly related to the monomers, proportions, structure, and molecular weight. For example, in the field of electronic chemicals, phenolic resins are the main component of G / I line photoresists, determining most of their properties and thus being a key design focus. The hydroxyl content on the benzene ring in the resin affects its solubility and contrast. To improve the sensitivity, heat resistance, contrast, resolution, and corrosion resistance of photoresists, phenolic resins with different structures have been designed. In the fields of coatings, plastics, rubber, and adhesives, the hydroxyl content, the type of substituents, and the structural design of the resin are also crucial for product development.

[0003] The properties of phenolic resins are closely related to their chemical structure; therefore, accurately describing the structure of phenolic resins is extremely important for resin development and application research. Summary of the Invention

[0004] The purpose of this application is to provide a method for determining hydroxyl groups in phenolic resins, which can quickly and accurately determine whether phenolic resins contain diphenols, and can also accurately calculate the content of hydroxyl groups and / or diphenols in phenolic resins.

[0005] The embodiments of this application are implemented as follows:

[0006] This application provides a method for determining hydroxyl groups in phenolic resin, including obtaining the hydroxyl group of the phenolic resin to be tested. 13 C-NMR spectra, and based on 13 The following interpretations can be made based on the C-NMR spectrum:

[0007] Determine if there is a signal at a displacement of 103±2ppm. If there is a signal, the phenolic resin to be tested contains diphenol.

[0008] And / or,

[0009] The signal at the integral displacement of 165–148 ppm is recorded as A1, the signal at the integral displacement of 148–144 ppm is recorded as A2, and the signal at the integral displacement of 144–95 ppm is recorded as A3. The content of hydroxyl groups and / or diphenols in the phenolic resin to be tested is calculated based on A1, A2, and A3.

[0010] In some possible implementations, calculating the hydroxyl and / or diphenol content in the phenolic resin to be tested according to A1, A2, and A3 includes:

[0011] Calculate the molar ratio of benzene ring hydroxyl groups and benzene ring carbons in the phenolic resin to be tested based on A1, A2, and A3;

[0012] And / or,

[0013] Calculate the molar percentage of diphenols in the phenolic resin to be tested based on A1, A2, and A3.

[0014] In some possible implementations, the molar ratio of benzene ring hydroxyl groups to benzene ring carbons in the phenolic resin to be tested is calculated using Formula 1, as follows:

[0015]

[0016] In some possible implementations, the molar percentage of diphenols in the phenolic resin to be tested is calculated using Formula 2, as follows:

[0017]

[0018] In some possible implementations, when integrating signals A1, A2, and A3, if the integration result is negative, the corresponding integration result is corrected to 0.

[0019] In some possible implementations, the structural formula of the phenolic resin to be tested is shown in Formula I below:

[0020]

[0021] Among them, at least one of the following conditions (a1) to (a4) must be satisfied;

[0022] (a1) The R group is an alkyl group or an aryl group containing a benzene ring structure;

[0023] (a2) The X group is an alkyl or aryl group;

[0024] (a3)n is 1 or 2;

[0025] (a4)m>2.

[0026] In some possible implementations, the phenolic hydroxyl groups of the diphenol in the phenolic resin to be tested are meta-substituted.

[0027] In some possible implementations, the X group includes at least one of methyl, ethyl, vinyl, propyl, and benzyl.

[0028] In some possible implementations, obtain 13 The testing conditions for C-NMR spectra include: a testing duration of 5 to 15 hours and 400 to 520 scans.

[0029] In some possible implementations, the scan ends, the free induction decay signal is acquired, and a Fourier transform is applied. The signal is then multiplied by an exponential function to obtain the spectrum, where LB = 2.0 Hz.

[0030] The beneficial effects of the method for determining hydroxyl groups in phenolic resin provided in this application include:

[0031] The assay method is based on the phenolic resin to be tested. 13 The C-NMR spectrum is used for analysis. Specifically, the presence of diphenols is determined based on signals at specific shifts, allowing for a relatively quick and accurate assessment of the presence of diphenols in phenolic resins. Furthermore, integrating the signals at characteristic shifts allows for a relatively accurate calculation of the hydroxyl and / or diphenol content in the phenolic resin. This content includes, for example, the molar ratio of hydroxyl groups to carbon atoms on the benzene ring and the molar percentage of diphenols. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 For example, the unknown sample 1 in Example 1 of this application 13 C-NMR spectrum;

[0034] Figure 2 For example, unknown sample 2 in Example 2 of this application 13 C-NMR spectrum;

[0035] Figure 3 For the known sample 1 in Test Example 1 of this application 13 C-NMR spectrum;

[0036] Figure 4 For the known sample 2 in Test Example 2 of this application 13 C-NMR spectrum;

[0037] Figure 5 For the known sample 3 in Test Example 3 of this application 13 C-NMR spectrum. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0039] It should be noted that the terms "and / or" in this application, such as "feature 1 and / or feature 2", all refer to the three cases of "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2".

[0040] In addition, in the description of this application, unless otherwise stated, "one or more" means two or more; the range of "numerical value a to numerical value b" includes the two endpoints "a" and "b"; and "unit of measurement" in "numerical value a to numerical value b + unit of measurement" represents the "unit of measurement" of both "numerical value a" and "numerical value b".

[0041] The method for determining the hydroxyl groups in the phenolic resin of this application will be described in detail below.

[0042] This application provides a method for determining hydroxyl groups in phenolic resin, including obtaining the hydroxyl group of the phenolic resin to be tested. 13 C-NMR spectra, and based on 13 The following interpretations can be made based on the C-NMR spectrum:

[0043] Determine if there is a signal at the 103±2ppm displacement. If there is a signal, the phenolic resin to be tested contains diphenols. And / or, the signal at the 165~148ppm displacement is recorded as A1, the signal at the 148~144ppm displacement is recorded as A2, and the signal at the 144~95ppm displacement is recorded as A3. Calculate the hydroxyl and / or diphenol content in the phenolic resin to be tested based on A1, A2, and A3.

[0044] In some possible implementations, obtain 13 The testing conditions for C-NMR spectra include: a testing duration of 5–15 hours and 400–520 scans. The testing duration is, for example, but not limited to, any one of 5 hours, 10 hours, and 15 hours, or any range between two of these values. The number of scans is, for example, but not limited to, any one of 400, 420, 440, 460, 480, 500, and 520, or any range between two of these values.

[0045] Furthermore, after the scan is completed, the free induction attenuation signal is acquired and Fourier transform is applied. The signal is then multiplied by an exponential function to obtain the spectrum, where LB = 2.0 Hz.

[0046] In some possible implementations, when acquiring A1, A2, and A3 using the integral signal, if the integration result is negative, the corresponding integration result is corrected to 0. That is, if the acquired A1 value is negative, the result of A1 is corrected to 0. The integration correction method for A2 and A3 is similar and will not be described again.

[0047] It should be noted that, in this application, when calculating the hydroxyl and / or diphenol content in the phenolic resin to be tested according to A1, A2 and A3, the types of hydroxyl and / or diphenols in the phenolic resin to be tested are not limited. They can be the molar ratio of benzene ring hydroxyl to benzene ring carbon in the phenolic resin to be tested, or the molar percentage of diphenols in the phenolic resin to be tested.

[0048] In some possible implementations, calculating the hydroxyl and / or diphenol content in the phenolic resin to be tested according to A1, A2, and A3 includes:

[0049] Calculate the molar ratio of benzene ring hydroxyl groups to benzene ring carbons in the phenolic resin to be tested based on A1, A2, and A3; and / or, calculate the molar percentage of diphenols in the phenolic resin to be tested based on A1, A2, and A3.

[0050] As a first example, the molar ratio of benzene ring hydroxyl groups to benzene ring carbons in the phenolic resin to be tested is calculated using Formula 1, as follows:

[0051]

[0052] In Formula 1, [OH] / C represents the molar ratio of hydroxyl groups and carbon atoms in the benzene ring of the phenolic resin to be tested.

[0053] As a second example, the molar percentage of diphenols in the phenolic resin to be tested is calculated using Formula 2, which is as follows:

[0054]

[0055] In Formula 2, 'diphenol,' represents the molar percentage of diphenol in the phenolic resin to be tested.

[0056] Research has shown that using the determination method provided in the embodiments of this application to detect phenolic resins with specific structures helps to ensure better detection accuracy. The following will provide illustrative examples of some phenolic resins with specific structures discovered in the research.

[0057] In some possible implementations, the structural formula of the phenolic resin to be tested is shown in Formula I below:

[0058]

[0059] Among them, at least one of the following conditions (a1) to (a4) must be satisfied;

[0060] (a1) The R group is an alkyl group or an aryl group containing a benzene ring structure;

[0061] (a2) The X group is an alkyl or aryl group;

[0062] (a3)n is 1 or 2;

[0063] (a4)m>2.

[0064] Regarding condition (a1), the R group can be a saturated alkyl group or an unsaturated alkyl group, which includes, for example, but not limited to, at least one of the elements C, H, O, N, S, P, etc.

[0065] Regarding condition (a2), the X group can be either a saturated group or an unsaturated group.

[0066] As an example, the X group includes at least one of methyl, ethyl, vinyl, propyl, and benzyl.

[0067] Regarding condition (a3), the value of n can be different in different structural units. When n is 1, it corresponds to a monohydric phenol, and when n is 2, it corresponds to a dihydric phenol. If the value of n is 3, the NMR signal will change, and the above formulas 1 and 2 cannot be used accurately for calculation.

[0068] As an example, meta-substitution of the phenolic hydroxyl groups in the diphenol in the phenolic resin to be tested is beneficial for applying Formula 1 and Formula 2 above to make accurate calculations.

[0069] Regarding condition (a4), m is, for example, a positive integer greater than or equal to 3.

[0070] The method for determining hydroxyl groups in phenolic resins provided in this application embodiment is based on the phenolic resin to be tested. 13 The presence of diphenols in phenolic resins can be determined relatively quickly and accurately by analyzing the signal at specific shifts. Furthermore, integrating the signal at characteristic shifts allows for the accurate calculation of the molar ratio of hydroxyl and carbon atoms in the benzene ring, as well as the molar percentage of diphenols.

[0071] The features and performance of this application will be further described in detail below with specific experimental examples.

[0072] I. Obtaining the phenolic resin to be tested 13 C-NMR spectrum

[0073] Approximately 50 mg of solid phenolic resin was placed in a glass container, and about 1 mL of deuterated solvent was added. The mixture was sonicated to dissolve the resin. If complete dissolution was not achieved, a small amount of solvent could be added to ensure complete dissolution. The resin solution was then transferred to an NMR sample tube for quantitative carbon NMR spectroscopy. The quantitative NMR spectroscopy conditions were as follows: test duration 10–15 h, 400–520 scans, direct dimension spectral width 37037.035 Hz, acquisition of the free induction decay (FID) signal, application of Fourier transform, and multiplication by an exponential function (LB = 2.0 Hz) to obtain the spectrum.

[0074] II. Based on13 Analysis of hydroxyl structure and content in the phenolic resin by C-NMR spectrum.

[0075] Example

[0076] Whether the phenolic resin to be tested contains diphenols, the molar ratio of benzene ring hydroxyl groups and benzene ring carbons, and the molar percentage of diphenols are all unknown. This is used to illustrate the determination method.

[0077] Example 1

[0078] The phenolic resin to be tested was unknown sample 1, the solvent was deuterated chloroform, the test duration was 10 hours, and the number of scans was 512. 13 C-NMR spectrum as shown Figure 1 As shown.

[0079] according to Figure 1 It can be seen that the sample has a strong signal at a displacement of 103±2ppm, indicating that the sample contains diphenols.

[0080] The integral signal A1 = 3.28 for displacement of 165–148 ppm, the integral signal A2 = 1.09 for displacement of 148–144 ppm, and the integral signal A3 = 10.14 for displacement of 144–95 ppm.

[0081] Calculate the molar ratio of hydroxyl groups and carbon atoms in the benzene ring according to Formula 1:

[0082]

[0083] Calculate the molar percentage of the diphenol using Formula 2:

[0084]

[0085] Example 2

[0086] The phenolic resin to be tested was unknown sample 2, the solvent was DMSO, the test duration was 7 hours, and the number of scans was 512. 13 C-NMR spectrum as shown Figure 2 As shown.

[0087] according to Figure 2 As can be seen, the sample showed no signal at a displacement of 103±2ppm, indicating that the sample did not contain diphenols.

[0088] The integral signal A1 = 0.85 for the displacement of 165-148 ppm, the integral signal A2 = -0.05 for the displacement of 148-144 ppm, the correction A2 = 0, and the integral signal A3 = 5.28 for the displacement of 144-95 ppm.

[0089] Calculate the molar ratio of hydroxyl groups and carbon atoms in the benzene ring according to Formula 1:

[0090]

[0091] Calculate the molar percentage of the diphenol using Formula 2:

[0092]

[0093] The molar percentage of diphenol is calculated as a negative number and corrected to 0, indicating that it does not contain diphenol, which is consistent with the judgment based on the presence or absence of a signal at a displacement of 103±2ppm.

[0094] Test case

[0095] The phenolic resin to be tested is a self-made product. Whether it contains diphenols, the molar ratio of hydroxyl groups and carbon atoms in the benzene ring, and the molar percentage of diphenols are all known. The accuracy of the test method is verified by comparing the known theoretical results with the test calculation results.

[0096] The preparation method of the phenolic resin to be tested is as follows:

[0097] A phenol monomer, formaldehyde, and an acid catalyst were added to a 500 ml detachable flask. The phenol monomer was selected from one or more of phenol, m-cresol, p-cresol, 3,5-xylenol, 2,3,5-trimethylphenol, resorcinol, methylresorcinol, methylbenzylresorcinol, and pentadecylresorcinol. The reactants were heated and stirred at 110–220 °C for 3 hours. After drying under reduced pressure, the mixture was cooled to obtain a phenolic resin.

[0098] Experimental Example 1

[0099] The phenolic resin to be tested is known sample 1, which... 13 C-NMR spectrum as shown Figure 3 As shown.

[0100] Given that the raw material molar ratio of sample 1 is m-cresol / p-cresol / formaldehyde = 1 / 1 / 0.6, the theoretical value is that the molar ratio of benzene ring hydroxyl group to benzene ring carbon is 1 / 6 = 0.167, and the molar percentage of diphenol is 0.

[0101] according to Figure 3 As can be seen, the sample showed no signal at a displacement of 103±2ppm, indicating that the sample did not contain diphenols.

[0102] The integral signal A1 for the displacement of 165-148 ppm is 14.27, the integral signal A2 for the displacement of 148-144 ppm is -0.75, the correction A2 is 0, and the integral signal A3 for the displacement of 144-95 ppm is 86.88.

[0103] Calculate the molar ratio of hydroxyl groups and carbon atoms in the benzene ring according to Formula 1:

[0104]

[0105] Calculate the molar percentage of the diphenol using Formula 2:

[0106]

[0107] The molar percentage of diphenol is calculated as a negative number and corrected to 0, indicating that it does not contain diphenol, which is consistent with the judgment based on the presence or absence of a signal at a displacement of 103±2ppm.

[0108] Experimental Example 2

[0109] The phenolic resin to be tested is known sample 2, whose... 13 C-NMR spectrum as shown Figure 4 As shown.

[0110] Given that the molar ratio of the raw materials for sample 2 is resorcinol / m-cresol / styrene / formaldehyde = 3 / 7 / 4.5 / 0.9, the theoretical value is the molar ratio of the hydroxyl group and the carbon group of the benzene ring. The molar percentage of the diphenol is 30%.

[0111] according to Figure 4 It can be seen that the sample has a strong signal at a displacement of 103±2ppm, indicating that the sample contains diphenols.

[0112] The integral signal A1 for the displacement of 165–148 ppm is 14.27, the integral signal A2 for the displacement of 148–144 ppm is 5.19, and the integral signal A3 for the displacement of 144–95 ppm is 82.34.

[0113] Calculate the molar ratio of hydroxyl groups and carbon atoms in the benzene ring according to Formula 1:

[0114]

[0115] Calculate the molar percentage of the diphenol using Formula 2:

[0116]

[0117] Experimental Example 3

[0118] The phenolic resin to be tested is known sample 3, whose... 13 C-NMR spectrum as shown Figure 5 As shown.

[0119] Given that the molar ratio of the raw materials for sample 3 is resorcinol / phenol / styrene / formaldehyde = 8.5 / 1.5 / 6.0 / 0.7, the theoretical value is the molar ratio of the hydroxyl group and the carbon group of the benzene ring.

[0120]

[0121] The molar percentage of the diphenol is 85%.

[0122] according to Figure 5 It can be seen that the sample has a strong signal at a displacement of 103±2ppm, indicating that the sample contains diphenols.

[0123] The integral signal A1 = 3.06 for displacement of 165–148 ppm, the integral signal A2 = 1.26 for displacement of 148–144 ppm, and the integral signal A3 = 14.98 for displacement of 144–95 ppm.

[0124] Calculate the molar ratio of hydroxyl groups and carbon atoms in the benzene ring according to Formula 1:

[0125]

[0126] Calculate the molar percentage of the diphenol using Formula 2:

[0127]

[0128] Some test conditions in Experiments 1-3 are shown in Table 1; whether the sample contains diphenol, the molar ratio of hydroxyl group and carbon group of benzene ring, the molar percentage of diphenol, and the statistical values ​​of its theoretical and calculated values ​​are shown in Table 1 below.

[0129] Table 1

[0130]

[0131] According to test examples 1-3 and Table 1:

[0132] The method for determining hydroxyl groups in phenolic resin provided in this application can quickly and accurately determine whether phenolic resin contains diphenols, and the molar ratio of benzene ring hydroxyl groups and benzene ring carbons and the molar percentage of diphenols calculated by the detection are highly accurate.

[0133] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for determining hydroxyl groups in phenolic resin, characterized in that, Including obtaining the phenolic resin to be tested 13 C-NMR spectra, and based on the 13 The following interpretations can be made based on the C-NMR spectrum: Determine if there is a signal at a displacement of 103±2ppm. If there is a signal, the phenolic resin to be tested contains diphenols; and / or, the signal at a displacement of 165~148ppm is recorded as A1, the signal at a displacement of 148~144ppm is recorded as A2, and the signal at a displacement of 144~95ppm is recorded as A3. Calculate the hydroxyl and / or diphenol content in the phenolic resin to be tested based on A1, A2, and A3. The calculation of the hydroxyl and / or diphenol content in the phenolic resin to be tested based on A1, A2, and A3 includes: Calculate the molar ratio of benzene ring hydroxyl groups and benzene ring carbons in the phenolic resin to be tested according to A1, A2 and A3; and / or calculate the molar percentage of diphenols in the phenolic resin to be tested according to A1, A2 and A3; The molar ratio of benzene ring hydroxyl groups to benzene ring carbons in the phenolic resin to be tested was calculated using Formula 1, as follows: ······（1）； The molar percentage of diphenols in the tested phenolic resin was calculated using Formula 2, as follows: ·····（2）； When integrating signals to obtain A1, A2, and A3, if the integration result is negative, the corresponding integration result is corrected to 0. The structural formula of the phenolic resin to be tested is shown in Formula I below: ...Formula I; Among them, at least one of the following conditions (a1) to (a4) must be satisfied; (a1) The R group is an alkyl group or an aryl group containing a benzene ring structure; (a2) The X group is an alkyl or aryl group; (a3) n is 1 or 2; (a4) m>2.

2. The method for determining hydroxyl groups in phenolic resin according to claim 1, characterized in that, The phenolic hydroxyl groups of the diphenol in the phenolic resin to be tested are meta-substituted.

3. The method for determining hydroxyl groups in phenolic resin according to claim 1, characterized in that, The X group includes at least one of methyl, ethyl, vinyl, propyl, and benzyl.

4. The method for determining hydroxyl groups in phenolic resin according to claim 1, characterized in that, Obtain the 13 The testing conditions for C-NMR spectra include: a testing duration of 5 to 15 hours and 400 to 520 scans.

5. The method for determining hydroxyl groups in phenolic resin according to claim 4, characterized in that, After the scan is completed, the free induction decay signal is acquired and Fourier transform is applied. The signal is then multiplied by an exponential function to obtain the spectrum, where LB = 2.0 Hz.

Images