CN107870136A - A kind of assay method of amphion sulfonated phenol formaldehyde resin cationic degree - Google Patents

Abstract

The invention relates to the technical field of chemical analysis, in particular to a method for determining the cationicity of zwitterionic sulfonated phenolic resins, comprising first _measuring the adsorption capacity m of every 0.5 g of pure zwitterionic sulfonated phenolic resins in diatomite, and then Bring in the formula A=863.87m_吸-24.54 to calculate the cationic degree A of the zwitterionic sulfonated phenolic resin. According to the cationic quaternary ammonium salt group on the molecular chain of the zwitterionic sulfonated phenolic resin, which has good adsorption properties, the present invention uses diatomite as a standard adsorption medium to calculate the adsorption mass according to the change in the mass of the sample to be tested before and after adsorption. The cationic degree determination method of the gravity method avoids the influence of anions on the determination process and measurement results in the prior art, improves the accuracy of the detection results, and has wide applicability and strong operability, and the equipment conditions require Low, can be popularized and applied in routine testing laboratories.

Description

A kind of determination method of cationic degree of zwitterionic sulfonated phenolic resin

technical field

The invention relates to the technical field of chemical analysis, in particular to a method for measuring the cationic degree of zwitterionic sulfonated phenolic resin.

Background technique

In recent years, with the development of drilling fluid treatment agents, cationic polymer treatment agents have shown good application effects in solving problems such as wellbore instability and clay mineral pollution to drilling fluids due to their excellent inhibition and anti-slump properties, reducing the Downhole complexity and reduction of comprehensive drilling costs are one of the research hotspots of oilfield chemists. Zwitterionic sulfonated phenolic resin is a synthetic resin based on sulfonated phenolic resin and introduced cationic groups. Due to the introduction of cationic groups in the molecular chain, the inhibition and anti-slump performance of the product are increased, and it is used as a common drilling fluid. Treatment agents are widely used.

The amount of cationic groups introduced into the zwitterionic sulfonated phenolic resin largely determines its anti-slump performance, and the suitable zwitterionic sulfonated phenolic resin is usually selected based on its cationic degree. However, the molecular chain of the zwitterionic sulfonated phenolic resin contains a large number of strong anionic hydration - SO ₃ ^2- groups. The conventional method for determining the cationicity of polymers is chemical analysis, including: tetraphenylborate sodium titration, colloid titration and phosphotungstic acid volumetric method are unable to form precipitation or neutralization reaction with precipitant or anionic polyelectrolyte because of the repulsion effect of strong anionic hydration -SO ₃ ^2- group. The literature "Preliminary Study on the Determination of Cationic Degree of Zwitterionic Sulfomethylphenol Formaldehyde Resin for Drilling Fluid" points out that the sodium tetraphenylborate titration method is not suitable for colored zwitterionic sulfomethylphenol formaldehyde resin, because the color of the filtrate interferes with the judgment of the end point of the indicator . In fact, the internal reason is that a large number of sulfonic acid groups in the molecular structure of the zwitterionic sulfomethylphenol-formaldehyde resin repel the tetraphenylborate, resulting in the inability to fully produce quaternary ammonium salt precipitation, and the degree of cation cannot be accurately measured. Even if the sodium tetraphenylborate weight method is used, the above phenomenon also exists, causing a large measurement deviation. Enterprise Standard Q/SH1025 0779-2011 "General Technical Specifications for Zwitterionic Sulfomethylphenolic Resins for Drilling Fluids" Although the anionic sulfonic acid groups are first eluted through the cation exchange resin, but not only the anionic groups There is a low elution rate and the loss of cationic groups, resulting in a large measurement deviation of the phosphotungstic acid volumetric method.

Therefore, it is urgent to establish a method suitable for the determination of the cationic degree of zwitterionic sulfonated phenolic resin.

Contents of the invention

In order to overcome the defects of the prior art, the object of the present invention is to provide a method for measuring the cationicity of zwitterionic sulfonated phenolic resin with accurate detection results and easy control of the operation process.

In order to achieve the above object, the technical solution adopted in the present invention is:

A method for measuring the cationic degree of zwitterionic sulfonated phenolic resin, comprising the following steps:

1) _Measure the adsorption capacity m of every 0.5g of pure zwitterionic sulfonated phenolic resin in diatomite;

2) Enter the formula A=863.87m _{to absorb} -24.54 to calculate the cationic degree A of the zwitterionic sulfonated phenolic resin.

Further, in step 1), the operation steps of the specific determination method of the _adsorption capacity m of every 0.5 g of pure zwitterionic sulfonated phenolic resin in diatomite are as follows:

a: Take 0.5 g of pure zwitterionic sulfonated phenolic resin and dissolve it in water to obtain a resin solution; then take diatomaceous earth with a mass of _m3 and add it to the resin solution, mix evenly, seal, and oscillate to obtain a solid-liquid mixed solution;

b: Take a filter paper with a mass of m ₄ , use the filter paper to separate the solid-liquid mixed solution prepared in step a, after the separation is completed, use the filter paper to cover the separated solid and dry it, then cool it to room temperature and weigh it as m ₅ , calculate the adsorption capacity m _absorption = m ₅ -m ₃ -m ₄ .

During the process of diatomite adsorbing zwitterionic sulfonated phenolic resin, the ratio of the amount of diatomite and zwitterionic sulfonated phenolic resin affects the adsorption performance between the two. According to experimental research, the saturated adsorption capacity of zwitterionic sulfonated phenolic resin on the surface of 1g diatomite is 41mg/g. In order to make the zwitterionic sulfonated phenolic resin fully adsorb on the diatomite, preferably, the mass _m3 of the diatomite is 2.0 g.

In order to further promote the complete adsorption process between the zwitterionic sulfonated phenolic resin and diatomite, preferably, the oscillation speed of the oscillation described in step a is 150r/min~200r/min, the oscillation temperature is 30~35°C, and the oscillation time 60~120min.

Further, the specific method of solid-liquid separation described in step b is: use filter paper to filter the solid-liquid mixed solution prepared in step a, collect the filtrate in a clean container, and use the collected filtrate to rinse the container containing the solid-liquid mixed solution. Container, filter the rinsed filtrate through filter paper again, and repeat the operation until the container containing the solid-liquid mixed solution is rinsed clean, which is completed.

Further, the drying in step b is drying at a temperature of 105±3° C. for 2 hours to 4 hours.

Further, it also includes firstly taking the zwitterionic sulfonated phenolic resin to be tested and purifying to obtain a pure zwitterionic sulfonated phenolic resin. The specific operation steps are:

A: Take the zwitterionic sulfonated phenolic resin to be tested and disperse it in the ethanol solution, let it stand for 20-40 minutes, then separate the solid from the liquid, collect the solid, and wash and dry the collected solid in turn to prepare a semi-pure product;

B: Dissolve the semi-pure product prepared in step 1) in water to obtain a semi-pure product solution; then centrifuge the semi-pure product solution for solid-liquid separation, collect the supernatant, and obtain a solution in which pure zwitterionic sulfonated phenolic resin is dissolved.

Further, the specific method of centrifuging solid-liquid separation in step B is: take the semi-pure solution and centrifuge it with a centrifuge at a speed of 2000-3000r/min for 15-20min, move the supernatant into a clean container, and wash the semi-pure solution with water. container, and collect the washing liquid, and perform centrifugal sedimentation again, repeat the above operation four times, and collect all the supernatant, which is completed.

Further, the drying in step A is drying at a temperature of 50±3°C for 4h~5h.

Further, in step A, the collected solid is washed with ethanol solution, and the mass concentration of the ethanol solution is 90%-95%.

Further, the above-mentioned diatomite and filter paper are all diatomite and filter paper dried at 105±3° C. to constant weight, wherein the filter paper is quantitative slow-speed filter paper.

In order to accurately obtain 0.5 _g of pure zwitterionic sulfonated phenolic resin, it also includes determining the water-insoluble content of the zwitterionic sulfonated phenolic resin to be tested. Dissolve in water, heat in a boiling water bath for 1 hour, centrifuge for sufficient solid-liquid separation, collect solid-phase sediment, dry at 105±2°C for 4 hours, then cool, weigh its mass as m ₂ , then the zwitterion sulfonium to be tested The mass percentage of water-insoluble matter in the phenolic resin is B= m ₂ /m ₁ ×100%. Using the measured water-insoluble mass percentage B, weigh the mass m ₆ of the semi-pure product prepared in step 1) in the above step B, then the mass m ₇ of the pure zwitterionic sulfonated phenolic resin in the semi-pure product = m ₆ -m ₆ ×B, that is, the mass of the pure zwitterionic sulfonated phenolic resin dissolved in the pure zwitterionic sulfonated phenolic resin prepared in step B is m ₇ , it can be calculated according to the 0.5 required in the actual measurement process g pure zwitterionic sulfonated phenolic resin, take the solution prepared in step B dissolved with pure zwitterionic sulfonated phenolic resin according to the ratio.

The method for measuring the cationic degree of the zwitterionic sulfonated phenolic resin of the present invention is based on the fact that the cationic quaternary ammonium salt group on the molecular chain of the zwitterionic sulfonated phenolic resin has good adsorption properties, and diatomaceous earth is used as a standard adsorption medium (adsorbent) for The mass change of 0.5g zwitterionic sulfonated phenolic resin before and after adsorption is used to calculate the adsorption mass, and the zwitterionic sulfonated phenolic resins with different cationic degrees correspond to different adsorption masses, and then brought into the 0.5g zwitterionic sulfonated phenolic resin summarized in the present invention The relationship between the adsorption amount and the cationic degree can be calculated to obtain the cationic degree of the actually measured zwitterionic sulfonated phenolic resin. The cationic degree determination method based on the adsorption weighing method of the present invention avoids the influence of anions on the determination process and measurement results in the prior art, improves the accuracy of the detection results, and has wide applicability and strong operability It is unique and has low requirements for equipment and equipment, so it can be popularized and applied in routine testing laboratories.

Furthermore, the determination method of the present invention purifies and removes the zwitterionic sulfonated phenolic resin to be tested, removes the interference factors, and obtains the pure zwitterionic sulfonated phenolic resin, further improving the accuracy of the detection result.

Description of drawings

Fig. 1 is the linear regression curve of the adsorption amount and cationic degree of zwitterionic sulfonated phenolic resin of embodiment.

Detailed ways

The technical solution of the present invention will be described in detail below through specific examples.

Example

The assay method of the cationic degree of zwitterionic sulfonated phenolic resin in this embodiment, the specific operation steps are:

1) Determination _of the adsorption capacity m of 0.5g of pure zwitterionic sulfonated phenolic resin in diatomite;

A: Determination of the mass percentage of water-insoluble matter:

a: Take the sample mass _m1 of the sample to be tested as 1.0004g (accurate to 0.0001g), put it in a 150mL beaker, add 100mL of distilled water, stir well, heat in a boiling water bath for 1h, and obtain the aqueous solution of the sample to be tested;

b: Transfer the aqueous solution of the sample to be tested prepared in step a into 6 centrifuge tubes that have been dried at 105±2°C to constant weight twice, and record the mass of the empty tubes of the 6 centrifuge tubes as m ₈ . Place the centrifuge tube in a centrifuge with a rotating speed of 3000r/min for 20 minutes, take out the ion tube, suck out the upper clear part with a straw and discard it;

c: Wash the residue in the beaker with 100mL distilled water for 4 times, transfer it to a centrifuge tube, settle by centrifugation, take out the centrifuge tube, suck out the upper clear part with a straw and discard;

d: Tilt the centrifuge tube into another clean beaker with constant weight, bake it in an oven at 105±2°C for 4 hours, move it into a desiccator, cool it to room temperature (not less than 30min), weigh the centrifuge tube as m ₉ , Then the mass m ₂ of the insoluble matter in the sample = m ₉ - m ₈ ;

e: Calculate the water-insoluble mass fraction B of the zwitterionic sulfonated phenolic resin of the sample to be tested according to the following formula:

B: Sample purification

a: Weigh a sample with a mass m ₁₀ of 2.05 g, place it in a 250 mL beaker, and slowly stir it with a glass rod, while adding 100 ml of ethanol solution with a mass concentration of 90%~95%, so that the sample is evenly dispersed in the ethanol solution , let stand for 30min.

b: Filter with a single layer of medium-speed qualitative filter paper dried to constant weight. After the filter is completed, wash the sample on the surface of the filter paper three times with 30ml of ethanol of the same concentration to remove the residual impurities on the surface of the sample;

c: Put the folded filter paper wrapped with the sample in a constant temperature drying oven, and dry it at 50±3°C for 4~5 hours, then immediately put the filter paper wrapped with the sample in the desiccator, cool to room temperature, and obtain half Pure;

C: remove water insoluble matter

a: Weigh 1.3242g of semi-pure product with mass _m6 , put it in a dry and clean 250 mL beaker, add 100 mL of distilled water, and stir at a low speed of 400r/min~500r/min on a magnetic stirrer to fully dissolve it. A semi-pure solution is obtained;

b: Use a centrifuge to centrifuge the above semi-pure product solution at 2500r/min for 18min, carefully transfer the upper solution into a clean 250mL volumetric flask with a straw, wash the residue in the beaker with 100mL distilled water repeatedly 4 times, and transfer it to a centrifuge tube. Settling by centrifugation, transfer the supernatant liquid to the above-mentioned volumetric flask with a straw, and set the volume to 250ml to obtain a solution in which pure zwitterionic sulfonated phenolic resin is dissolved; the content of pure zwitterionic sulfonated phenolic resin in the solution is m ₇ =m ₆ ×(1-B)=1.3242×0.944=1.25g;

D: Determination of adsorption capacity by adsorption weighing method

a: Use a 100ml pipette to accurately pipette 100ml of the above-mentioned solution dissolved in pure zwitterionic sulfonated phenolic resin, and place it in a dry and clean 250mL conical flask; use weighing paper to weigh the mass _m3 to 2.0002g, Diatomite dried at ±3°C to constant weight, poured into the above-mentioned Erlenmeyer flask, mixed the solid and liquid, sealed the mouth of the bottle with plastic wrap, and placed the Erlenmeyer flask in a constant temperature dual-function oscillator to shake for 120min. The oscillation mode is rotary, the oscillation temperature is 32°C, and the oscillation speed is 180r/min;

b: After the oscillation is over, put the dry and clean funnel on the funnel holder first, put a single layer of filter paper in the funnel that has been dried to constant weight and has a known mass _m4 of 1.9867g, and then put the solid-liquid in the Erlenmeyer flask Slowly pour the mixture into the filter paper, collect the filtrate with a dry and clean 100mL beaker under the funnel, and at the same time use the collected filtrate to wash the solid particles adhered to the inner wall of the Erlenmeyer flask, and pour the filtrate into the filter paper again, repeating 4 times until the The solid particles on the inner wall of the Erlenmeyer flask are washed away;

c: After the filtrate is filtered, put the folded filter paper wrapped with diatomaceous earth in a dry and clean weighing bottle, and dry it at 105°C±3°C for 2 hours; after drying, put the filter paper wrapped with diatomaceous earth immediately Put it in a desiccator, and after cooling for 20 minutes, weigh the mass _m5 to be 4.0241g;

d: Calculation of adsorption m _absorption = m ₅ -m ₃ -m ₄ =4.0241g-1.9867g-2.0002g=0.0372g

2) Calculation of cationic degree: Put the adsorption _amount mab calculated in step 1) into the formula A=863.87× _mab -24.54, and calculate the cationic degree A=863.87×0.0372-24.54=7.6%.

The formula A=863.87×m_向-24.54 is obtained by the following method: According to the method of the above step 1), the laboratory determined that the cationic degree was determined to be 2.10%, 4.04%, 6.38%, 8.46%, and 11.02 respectively by elemental analysis. %, 13.34% and 15.12% of the adsorption mass of zwitterionic sulfonated phenolic resin, the linear regression equation curve of cationic degree and adsorption mass is obtained through mathematical regression analysis, as shown in Figure 1, that is, the relationship between cationic degree and adsorption mass The relational formula is A =863.87m _suction -24.54, R ² =0.9978.

Comparative example 1

This comparative example is the cationic degree of the zwitterionic sulfonated phenolic resin measured by the sodium tetraphenyl borate gravimetric method, and the specific operation steps are:

1) Prepare a solution in which pure zwitterionic sulfonated phenolic resin is dissolved in the same manner as step A, step B and step C in the above examples;

2) Determination of cationic degree:

a: Use a 100mL pipette to accurately pipette 100ml of the above-mentioned solution dissolved in pure zwitterionic sulfonated phenolic resin, add 2~3 drops of phenolphthalein indicator to a 200mL beaker, and adjust the solution with 10% sodium hydroxide to a clear red. Add 8 mL of formaldehyde solution, if the red color disappears at this time, add a few drops of sodium hydroxide to adjust to red color. Cover with a watch glass, and heat the solution on a boiling water bath for 10 min. At this point the solution remains red. Remove the beaker and cool slightly, add 10mL sodium tetraphenylborate standard solution drop by drop under stirring, continue to stir for 1 min, cool rapidly to below 20°C, and place for 10 min;

b: Suction filtration with the No. 4 glass sand core crucible which was pre-dried at 120°C±2°C to constant weight, first suction filter the supernatant liquid, then transfer the precipitate to the crucible with the washing liquid, and continue to wash the precipitate 10 times with the washing liquid ,. The amount of each washing liquid is about 5mL, and the crucible is dried at 120℃±2℃ to constant weight, and its weight is measured as m ₁₀ .

c: Calculation of cationic degree: cationic degree A(%)=m ₁₀ /m×0.4845×100%

In the formula:

m ₁₀ -- the mass of tetraphenylammonium boride after drying, g:

m - the mass of pure zwitterionic sulfonated phenolic resin contained in a solution of pure zwitterionic sulfonated phenolic resin dissolved in 100ml, g:

0.4845--The conversion coefficient of ammonium tetraphenyl boride to quaternary ammonium salt.

Cationic degree A=0.0477/0.5000×0.484 5×100%=4.62%

Comparative example 2

This comparative example is the cationic degree of the zwitterionic sulfonated phenolic resin measured by the phosphotungstic acid titration method, and the specific operation steps are:

1) Prepare a solution in which pure zwitterionic sulfonated phenolic resin is dissolved in the same manner as step A, step B and step C in the above examples;

2) Determination of cationic degree:

a: Treat the cation exchange resin into sodium form, accurately pipette the above-mentioned solution containing 1.100g of pure zwitterionic sulfonated phenolic resin through the treated cation exchange resin, wash with distilled water until it is colorless, and wash it with 60 ℃ ~ 70 80mL of 20% sodium chloride at ℃ to elute the resin at a rate of 5 mL/min to 6 mL/min, the eluent is adjusted to a pH value of 3 to 4 with 1mol/L hydrochloric acid, and the elution effluent is collected;

b: Add 6-8 drops of Congo red indicator to the elution effluent collected above, titrate with phosphotungstic acid standard solution, after precipitation is formed (no precipitation, indicating that the sample has no cations), slowly titrate until the red color is completely disappeared, and the solution was pure blue as the end point.

c: Calculation: cationic degree A(%)=(10 ^-3 CV/m)×2880×100%

C——molar concentration of phosphotungstic acid, in moles per liter (mol/L);

V - the volume of phosphotungstic acid consumed, in milliliters (mL);

m——sample mass, in grams (g);

2880——Molar mass of phosphotungstic acid, g/mol.

Cationic degree A = (10 ^-3 × 0.0206 × 0.700/1.100) × 2880 × 100% = 3.8%

Test example 1

Comparative example, comparative example 1 and comparative example 2 are to the measurement result size of the cationic degree of same amphoteric sulfonated phenolic resin, and the result shows embodiment > comparative example 1 > comparative example 2, by this result we can know that due to being subjected to anion and thinking operation Influenced by judgment error, the result of the determination of the cationic degree is low, but the method described in the embodiment overcomes the above-mentioned defects and improves the accuracy of the measured result of the cationic degree.

Test Example 2 Accuracy Verification Test

Test method: 4 amphoteric ion sulfonated phenolic resin samples with different cationic degrees synthesized in the laboratory were washed with alcohol, and the nitrogen element analysis was carried out by atomic absorption spectroscopy and the cationic degree of the same sample was measured by the measurement method provided in the embodiment of the present invention. , and the results are compared as shown in Table 1 below:

Sample serial number 1 2 3 4 Elemental Analysis 2.05% 5.10 6.42 12.45 The method described in the embodiment 2.00% 5.04 6.36 12.40 standard deviation 2.40% 1.20% 0.93% 0.40%

Conclusion: The cationic degree of zwitterionic sulfonated phenolic resin determined by the adsorption weighing method provided by the present invention is basically consistent with the measured value of the cationic degree obtained by the elemental analysis method, and the relative errors of the four samples are all less than 2.5%. It can be seen that the adsorption weighing method provided by the present invention is accurate and reliable for determining the cationic degree of the zwitterionic sulfonated phenolic resin.

Claims (10)

1. a kind of assay method of amphion sulfonated phenol formaldehyde resin cationic degree, it is characterised in that including following operating procedure：

1）Measure is per adsorbance m of the amphion sulfonated phenol formaldehyde resin pure 0.5g in diatomite_Inhale；

2）Bring formula A=863.87m into_Inhale- 24.54, the cationic degree A of amphion sulfonated phenol formaldehyde resin is calculated.

2. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 1, it is characterised in that step 1）In per adsorbance m of the amphion sulfonated phenol formaldehyde resin pure 0.5g in diatomite_InhaleSpecific assay method operation Step is：

a：The amphion sulfonated phenol formaldehyde resin for taking 0.5g pure is added to the water dissolving, obtains resin solution；It is m to take quality afterwards₃'s Diatomite is added in resin solution, is well mixed, and is sealed, and vibration, obtains solid-liquid mixed solution；

b：It is m to take quality₄Filter paper, the solid-liquid mixed solution for being prepared step a using the filter paper carried out separation of solid and liquid, separated After being dried after finishing using the solid of filter paper cladding separation, it is referred to as m to be cooled to room temperature its weight₅, calculate adsorbance m_Inhale=m₅- m₃-m₄。

3. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 2, it is characterised in that described Diatomaceous quality m₃For 2.0g.

4. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 2, it is characterised in that step The vibration rotating speed vibrated described in a is 150r/min ~ 200r/min, and vibration temperature is 30 ~ 35 DEG C, and duration of oscillation is 60 ~ 120min.

5. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 2, it is characterised in that step The specific method of separation of solid and liquid described in b is：Solid-liquid mixed solution prepared by step a is filtered using filter paper, with clean Container collection filtered fluid, and with collect filtered fluid rinse contain solid-liquid mixed solution container, by the filtered fluid after flushing Again filtered by filter paper, repeat to the container for containing solid-liquid mixed solution and rinse well, that is, complete.

6. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 2, it is characterised in that step Dried described in b is that 2h ~ 4h is dried at a temperature of 105 ± 3 DEG C.

7. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 1, it is characterised in that also wrap Include and take amphion sulfonated phenol formaldehyde resin to be measured to carry out the amphion sulfonated phenol formaldehyde resin that purifying is made pure, specific behaviour first It is as step：

A：Take amphion sulfonated phenol formaldehyde resin to be measured to be dispersed in ethanol solution, after standing 20 ~ 40min, carry out separation of solid and liquid, Solid is collected, and the solid of collection is washed, after drying successively, prepares half sterling；

B：Take step 1）Half sterling prepared is dissolved in water, and obtains half sterling solution；Afterwards by half sterling solution centrifugal solid-liquid point From, collect supernatant, obtain the solution dissolved with pure amphion sulfonated phenol formaldehyde resin.

8. the assay method of amphion sulfonated phenol formaldehyde resin cationic degree as claimed in claim 7, it is characterised in that step The specific method of centrifugal solid-liquid separation is in B：Take half sterling solution centrifuge with 2000 ~ 3000r/min rotating speeds centrifugation 15 ~ 20min, supernatant is moved into clean container, the container for containing semi-finished product solution is washed with water, and collect cleaning solution, entered again Row centrifugal sedimentation, repeats aforesaid operations four times, collects whole supernatants, that is, completes.

9. the assay method of amphion sulfonated phenol formaldehyde resin ion degree as claimed in claim 7, it is characterised in that step A Described in dry be at a temperature of 50 ± 3 DEG C dry 4h ~ 5h.

10. the assay method of which resin ion degree is removed in amphion sulfonation as claimed in claim 7 point, it is characterised in that step The solid of collection is washed using ethanol solution in rapid A, the mass concentration of the ethanol solution is 90% ~ 95%.