CN109828081A - The preparation method of blank solution in a kind of PT base number measuring method - Google Patents
The preparation method of blank solution in a kind of PT base number measuring method Download PDFInfo
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- CN109828081A CN109828081A CN201910115962.4A CN201910115962A CN109828081A CN 109828081 A CN109828081 A CN 109828081A CN 201910115962 A CN201910115962 A CN 201910115962A CN 109828081 A CN109828081 A CN 109828081A
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- sodium hydroxide
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Abstract
The present invention provides a kind of preparation methods of blank solution in PT base number measuring method, the following steps are included: step 1: the methanol solution that 9500ml content is 99.9% being added in vial, 400ml distilled water is added in methanol solution again, the sodium hydroxide solution of the 0.5mol/L of 0.8ml is added, stirs the methanol solution that sodium hydroxide is made in 8h for the first time;Step 2: the methanol solution room temperature opening of the sodium hydroxide in step 1 is stood;Step 3: carrying out second to the methanol solution of the sodium hydroxide in step 2 and stir, cover the methanol blank solution that bottle cap obtains sodium hydroxide, spare.Blank solution in the polytetrahydrofuran base number measurement prepared using the present invention, is reduced the measurement number of blank solution, improves the base number accuracy of measurement of PT, and the product qualified rate of PT product improves.
Description
Technical field
The present invention relates to blank in the detection method technical field of polytetrahydrofuran more particularly to a kind of PT base number measuring method
The preparation method of solution.
Background technique
Polytetrahydrofuran (PTMEG hereinafter referred PT) is also known as polytetrahydrofuran diol, polytetramethylene ether diol, poly- four Asia
Methyl glycol, polybutadiene alcohol ether, polybutadiene ether are that one kind is easily soluble in alcohol, ester, ketone, aromatic hydrocarbons and chlorinated hydrocabon, do not dissolve in ester fat hydrocarbon
With the white waxy solid of water, polytetrahydrofuran room temperature white solid is colourless transparent liquid after thawing, when temperature is more than room temperature
When will become transparency liquid.PT can in multiple industrial applications such as clothes, medical treatment, machine-building, be such as applied to tire, transmission belt,
Washer, coating, artificial leather, film, polyurethane elastomeric fiber, medical macromolecular materials etc..
The PT of different product, which needs to control its base number, needs to add sulfuric acid solution to PT's in certain range, production
Base number is adjusted, therefore the base number of the semi-finished product and finished product to PT needs frequent measurement.The base number of PT passes through constant-current titration
Method measurement, titrating solution hydrochloric acid solution, blank solution are the methanol solution of sodium hydroxide.The calculation formula of PT base number are as follows:
Wherein: V1It titrates number (ml);V0Blank solution (ml);C(HCl)The concentration of standard solution;M- sample weighting amount.
PT semi-finished product and finished product find that the stability and accuracy of base number measurement result are inadequate in the detection, lead to base number
Measurement result error is larger.Independent analysis is carried out by multifactor multi-parameter, base number measurement may be influenced by following factor:
1. although measurement beaker and magnetic stir bar are cleaned as required but base number measurement is sensitiveer, it would still be possible to have an impact;2. titration
Pipe may inaccuracy;3. potentiometric analyzer control system problem causes titration data may inaccuracy;4. titrating solution concentration occurs
Variation.By to the above 4 aspect factor carry out independent analysis discovery, base number measure it is unstable and it is inaccurate be by blank solution
Caused by preparation method.Wherein, the preparation method of existing blank solution is: 9500ml methanol solution is added in vial,
400ml distilled water and 0.8ml content are added as the sodium hydroxide solution of 0.5mol/L, mixed solution is made in stirring 8h, will be empty
White solution uses after placing at least 5h.The reason that the methanol solution stability of blank solution sodium hydroxide is bad is: the hydrogen of addition
The reactions such as the micro formic acid in carbon dioxide, methanol in sodium oxide molybdena and air generate the objects such as sodium carbonate, sodium bicarbonate, sodium formate
Matter, these types of substance and Carbon Dioxide in Air are dissolved into the carbonic acid generated in solution and are formed in methanol solution similar to one kind
, there are larger impact in very weak buffer solution, the stabilization of this buffer solution whether to the measurement of blank solution.
In view of this, it is necessary to which the preparation method of blank solution in the base number measuring method of PT in the prior art is given
It improves, to solve the above problems.
Summary of the invention
The purpose of the present invention is to provide blank solution in the base number measuring method of PT a kind of, (methanol of sodium hydroxide is molten
Liquid) preparation method, the stability of blank solution and accuracy are good after improvement, and when use reduces the measurement time of blank solution
Number, improve the accuracy of measurement of the base number of PT, accelerate PT product analysis and control analysis speed, improve PT semi-finished product and
The qualification rate of finished product.
Realize that the technical solution of goal of the invention is as follows: the preparation method of blank solution in a kind of PT base number measuring method, including
Following steps:
Step 1: 9500ml content is added in vial and is 99.9% methanol solution, then is added in methanol solution
400ml high purity water, is added the sodium hydroxide solution of the 0.5mol/L of 0.8ml, stirs the methanol that sodium hydroxide is made in 8h for the first time
Solution;
Step 2: the methanol solution room temperature opening of the sodium hydroxide in step 1 is stood;
Step 3: second is carried out to the methanol solution of the sodium hydroxide in step 2 and is stirred, bottle cap is covered and obtains hydroxide
The methanol blank solution of sodium, it is spare.
Wherein, in step 3, blank solution makes after room temperature lower open mouth placement >=5h before use, carry out third time stirring again
With.After being stirred by third time, blank solution room temperature lower open mouth is placed, it is ensured that the buffering formed in sodium hydrate methanol solution
Solution reaches stable, and the carbon dioxide dissolved in the solution reaches balance.
Preferably, in order to improve stability when blank solution measurement, blank solution can be increased by improving stirring intensity
Stability, when specific stirring for the first time, second of stirring, third time stir, the center of the methanol solution of sodium hydroxide
Whirlpool depth >=7cm.The stirring intensity for improving blank solution can be such that the carbon dioxide being dissolved in sodium hydrate methanol solution passes through
Constantly dissolution and release are crossed, the carbon dioxide in solution is made to reach balance, and makes to be formed in sodium hydrate methanol solution slow
It rushes solution and reaches stable.
Preferably, third time mixing time >=1h.
Wherein, in step 3, the time of second of stirring is 8h.
Wherein, in step 2, the methanol solution opening time of repose of sodium hydroxide is 12h.
Wherein, in step 1, in water containing a variety of salt such as calcium, magnesium, iron and organic matter, microorganism, etc., prepared with water
To reduce influence of the impurities in water to test solution when test solution, the distilled water of the methanol blank solution of sodium hydroxide is prepared using high-purity
Water, by high purity water prepare blank solution, can avoid because the purity of distilled water not enough due to influence blank solution measurement result and
Stability.
Compared with prior art, the invention has the advantage that:
1. after the preparation method of improved blank solution, the blank determination of blank solution is stablized, empty after a period of use
White solution blank determination value variation is within the allowable range.
2. improving the preparation method of blank solution, after PT production application, number and the blank for reducing blank determination are molten
The number that liquid is prepared, it is noted that the accuracy of determination data provides robust techniques for the normal production control of enterprise's PT product
It ensures, checks on for the quality inspection of factory and provide solid guarantee, improve the quality of PT product.
3. the preparation of improved blank solution, the evaluated error used in continuous 2~5 days is controlled in 0.1meqOH/
Within 30Kg, the error of more former blank solution preparation method is greatly reduced.
Detailed description of the invention
Fig. 1 is the blank solution repetition measurement result line chart of sample 1 in table one in the embodiment of the present invention 2;
Fig. 2 is the blank solution repetition measurement result line chart of sample 2 in table one in the embodiment of the present invention 2;
Fig. 3 be the embodiment of the present invention 2 in semi-finished product 1, semi-finished product 2, finished product 1, finished product 2 PT base number measurement result folding
Line chart.
Specific embodiment
Invention is described in detail below by each embodiment, but it should be stated that, these embodiments are not
Limitation of the present invention, those of ordinary skill in the art are according to these embodiments in made function, method or structure
Equivalent transformation or substitution, all belong to the scope of protection of the present invention within.
In addition, term " first ", " second ", " third " etc. are used for description purposes only, it is not understood to indicate or imply
Relative importance or the quantity for implicitly indicating indicated technical characteristic.The feature of " first ", " second " etc. is defined as a result,
It can explicitly or implicitly include one or more of the features.In the description of the invention, unless otherwise indicated,
The meaning of " plurality " is two or more.
Embodiment 1:
Present embodiment provides a kind of preparation method of blank solution in PT base number measuring method, comprising the following steps:
Preparation before solution is prepared, by vial, the magneton of agitating device, graduated cylinder, beaker, base buret, glass
Bottle bottle stopper etc. is cleaned 3~5 times repeatedly with distilled water, spare after drying.
Step 1: 9500ml content is added in vial and is 99.9% methanol solution, then is added in methanol solution
The sodium hydroxide solution of 400ml high purity water and 0.8ml, 0.5mol/L uses magnetic with 2~3 magnetons of magneton are put into vial
Power agitating device is stirred, and stirs the methanol solution that sodium hydroxide is made in 8h for the first time;
Step 2: the methanol solution room temperature lower open mouth of the sodium hydroxide in step 1 is stood into 12h;
Step 3: second of stirring 8h is carried out to the methanol solution of the sodium hydroxide in step 2, bottle cap is covered and obtains hydrogen-oxygen
Change the methanol blank solution of sodium, it is spare.
Wherein, stirring for the first time, second of stirring, adjust the mixing speed of magnetic stirring apparatus, make hydrogen-oxygen in vial
The whirlpool depth for changing the center of the methanol solution of sodium is 9 ± 2cm.
Embodiment 2:
Present embodiment provides the preparation method of blank solution in another kind PT base number measuring method, comprising the following steps:
Preparation before solution is prepared, by vial, the stirring rod of agitating device, graduated cylinder, beaker, base buret, glass
Glass bottle bottle stopper etc. is cleaned 3~5 times repeatedly with distilled water, spare after drying.
Step 1: 9500ml content is added in vial and is 99.9% methanol solution, then is added in methanol solution
Stirring rod is put into vial and is carried out with agitating device by the sodium hydroxide solution of 400ml high purity water and 0.8ml, 0.5mol/L
The methanol solution of sodium hydroxide is made through first time stirring 8h for stirring;
Step 2: the methanol solution room temperature lower open mouth of the sodium hydroxide in step 1 is stood into 12h;
Step 3: second of stirring 8h is carried out to the methanol solution of the sodium hydroxide in step 2, bottle cap is covered and obtains hydrogen-oxygen
Change the methanol blank solution of sodium, it is spare.
Wherein, stirring for the first time, second of stirring, adjust the rotation speed of the stirring rod of agitating device, make in vial
The whirlpool depth at the center of the methanol solution of sodium hydroxide is 11 ± 2cm.
1. the methanol blank solution of the sodium hydroxide of embodiment 1 and embodiment 2 also needs to carry out third time stirring using preceding:
Specifically, the rotation speed (or power of magnetic stirring apparatus) of the stirring rod of adjustment agitating device, makes hydrogen-oxygen in vial
The whirlpool depth for changing the center of the methanol solution of sodium is no less than 7cm, and after stirring at least 1 hour, room temperature lower open mouth is placed at least
It is used after 5 hours.
The measurement result of the base number of 2.PT compares:
Repetition measurement is as a result, see the table below one and specification in blank solution 1~3 day prepared before 2.1 uses improve and after improving
Shown in attached drawing 1~2.
Table one: blank solution is measurement result tables of data;
Figure one: the blank solution repetition measurement result line chart of sample 1 in table one (see Figure of description 1);
Figure two: the blank solution repetition measurement result line chart of sample 2 in table one (see Figure of description 2).
Table one:
Analysis: by table one, Fig. 1~2 it is found that the methanol blank solution of 1. sodium hydroxides prepared using the method before improving
In three days when different time sections repetition measurement, the base number amplitude of variation of the methanol blank solution of sodium hydroxide is very big, is using every time
When require to carry out repetition measurement to the methanol blank solution of sodium hydroxide, otherwise can seriously affect sample detection measurement stability and
Accuracy;2. different in three days using the methanol blank solution for the sodium hydroxide that the method for (i.e. of the invention) after improving is prepared
When period carries out repetition measurement, the base number of blank solution is relatively stable, does not need the alkali carry out to blank solution when in use
Value carries out correction repeatedly, improves the efficiency of the detection of PT base number in production.
2.2 in 1~3 day using improve before and improve after prepare blank solution measurement PT base number as a result, specific
It see the table below two, Figure of description 3.
Table two: semi-finished product 1, semi-finished product 2, finished product 1, finished product 2 PT base number measurement result tables of data;
Fig. 3: semi-finished product 1, semi-finished product 2, finished product 1, finished product 2 PT base number measurement result line chart (see Figure of description
3)。
Table two:
Analysis: by table two and Fig. 3 it will be evident that the methanol blank solution using improved sodium hydroxide measures PT's
When base number, finished product and semi-finished product carry out repetition measurement in 1~3 day, measurement result is relatively stable, and as a result accuracy was high, at 1~3 day
When interior different time sections are measured PT base number, do not need to carry out blank solution correction repeatedly, improve PT in production
The efficiency of the detection of product base number.
The series of detailed descriptions listed above only for feasible embodiment of the invention specifically
Protection scope bright, that they are not intended to limit the invention, it is all without departing from equivalent implementations made by technical spirit of the present invention
Or change should all be included in the protection scope of the present invention.
It is obvious to a person skilled in the art that invention is not limited to the details of the above exemplary embodiments, Er Qie
In the case where without departing substantially from spirit or essential attributes of the invention, the present invention can be realized in other specific forms.Therefore, no matter
From the point of view of which point, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the present invention is by appended power
Benefit requires rather than above description limits, it is intended that all by what is fallen within the meaning and scope of the equivalent elements of the claims
Variation is included within the present invention.
Claims (7)
1. the preparation method of blank solution in a kind of PT base number measuring method, it is characterised in that: the following steps are included:
Step 1: 9500ml content is added in vial and is 99.9% methanol solution, then 400ml is added in methanol solution
The sodium hydroxide solution of the 0.5mol/L of 0.8ml is added in distilled water, and the methanol that sodium hydroxide is made through first time stirring 8h is molten
Liquid;
Step 2: the methanol solution room temperature opening of the sodium hydroxide in step 1 is stood;
Step 3: second is carried out to the methanol solution of the sodium hydroxide in step 2 and is stirred, bottle cap is covered and obtains sodium hydroxide
Methanol blank solution, it is spare.
2. the preparation method of blank solution in a kind of PT base number measuring method according to claim 1, it is characterised in that: step
In three, the blank solution is used after room temperature lower open mouth placement >=5h before use, carry out third time stirring again.
3. the preparation method of blank solution in a kind of PT base number measuring method according to claim 2, it is characterised in that: described
When stirring for the first time, second of stirring, third time stir, the whirlpool depth >=7cm at the center of the methanol solution of sodium hydroxide.
4. the preparation method of blank solution in a kind of PT base number measuring method according to claim 2, it is characterised in that: third
Secondary mixing time >=1h.
5. the preparation method of blank solution in a kind of PT base number measuring method according to claim 1, it is characterised in that: step
In three, the time of second of stirring is 8h.
6. the preparation method of blank solution in a kind of PT base number measuring method according to claim 1, it is characterised in that: step
In two, the methanol solution opening time of repose of the sodium hydroxide is 12h.
7. the preparation method of blank solution in a kind of PT base number measuring method according to claim 1, it is characterised in that: step
In one, the distilled water is high purity water.
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CN112782261A (en) * | 2020-12-28 | 2021-05-11 | 新疆美克化工股份有限公司 | 1, 4-butanediol base number analysis method |
Citations (1)
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RU2305831C1 (en) * | 2006-06-27 | 2007-09-10 | Государственное образовательное учреждение высшего профессионального образования Воронежская государственная технологическая академия | Method for determination of valine in aqueous solutions |
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Publication number | Priority date | Publication date | Assignee | Title |
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RU2305831C1 (en) * | 2006-06-27 | 2007-09-10 | Государственное образовательное учреждение высшего профессионального образования Воронежская государственная технологическая академия | Method for determination of valine in aqueous solutions |
Non-Patent Citations (2)
Title |
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美国标准: "《Standard Test Method for Base Number Determination by Potentionmetric Hydrochloric Acid Titration》", 31 July 2011 * |
郑光等: "快速测定润滑油碱值方法的探讨", 《测试与评定》 * |
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CN112782261A (en) * | 2020-12-28 | 2021-05-11 | 新疆美克化工股份有限公司 | 1, 4-butanediol base number analysis method |
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