CN102944554A - Rapid paraformaldehyde content measuring method - Google Patents

Rapid paraformaldehyde content measuring method Download PDF

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Publication number
CN102944554A
CN102944554A CN 201210451696 CN201210451696A CN102944554A CN 102944554 A CN102944554 A CN 102944554A CN 201210451696 CN201210451696 CN 201210451696 CN 201210451696 A CN201210451696 A CN 201210451696A CN 102944554 A CN102944554 A CN 102944554A
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Prior art keywords
paraformaldehyde
solution
sulfuric acid
acid standard
rapid
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CN 201210451696
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Chinese (zh)
Inventor
于凤兰
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Tianjin Chemical Reagent Research Institute
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Tianjin Chemical Reagent Research Institute
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Priority to CN 201210451696 priority Critical patent/CN102944554A/en
Publication of CN102944554A publication Critical patent/CN102944554A/en
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Abstract

The invention relates to a rapid paraformaldehyde content measuring method which is characterized by comprising the following steps of: weighting 0.0001g of paraformaldehyde samples and putting the paraformaldehyde samples in a conical flask; adding a sodium hydroxide solution and then adding a hydrogen peroxide solution till the reaction is complete; cooling to room temperature; adding a bromothymol blue indicating liquid; and titrating with a sulfuric acid standard volumetric solution until the solution becomes cyan, wherein the reaction temperature is room temperature. According to the rapid paraformaldehyde content measuring method, the paraformaldehyde content is measured by a acid-base titration method at the room temperature; and the rapid paraformaldehyde content measuring method has the advantages of simplicity, rapidness, high accuracy, high precision and good reproducibility.

Description

The rapid assay methods of paraformaldehyde content
Technical field
The present invention relates to organic compound content assay method field, particularly a kind of rapid assay methods of paraformaldehyde content.
Background technology
Paraformaldehyde is important organic industry raw material, is widely used in the aspects such as synthetic resin, bonding agent, medicine.Domestic production and the producer that uses paraformaldehyde adopt sulphite process or iodimetric titration usually to the mensuration of paraformaldehyde content, although this assay method is classical, operation intermediate link influence factor is more, time-consuming, easily produces error.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, provide a kind of simple, quick, accuracy is high, precision is high, under the room temperature of favorable reproducibility with the method for determination of acid-basetitration industry paraformaldehyde content.
The present invention realizes that the technical scheme of purpose is as follows:
A kind of rapid assay methods of paraformaldehyde content, step is as follows:
Take by weighing the paraformaldehyde sample, be accurate to 0.0001g, place conical flask, add sodium hydroxide solution, add again superoxol to reacting completely, be cooled to room temperature, add the bromthymol blue indicator solution, be titrated to solution with the sulfuric acid standard titration solution and become blue-green, temperature of reaction is room temperature;
Paraformaldehyde content X% is calculated as follows:
X = ( V 0 - V ) C × 3.003 m × 100
In the formula:
The content of X-paraformaldehyde, in formaldehyde, %;
The concentration of C-sulfuric acid standard titration solution, mol/L;
The volume of the sulfuric acid standard titration solution that V-titration sample consumes, ml;
V 0The volume of the sulfuric acid standard titration solution that-titration blank consumes, ml;
3.003-with 1.00ml sulfuric acid standard titration solution C(1/2H 2SO 4)=1mol/L, g;
The quality of m-sample, g.
Advantage of the present invention and beneficial effect are:
Paraformaldehyde content of the present invention adopts acid base titration under the room temperature, method has simply, fast, accuracy is high, precision is high, the advantage of favorable reproducibility.
Embodiment
Below in conjunction with embodiment, following embodiment is illustrative, is not determinate, can not limit protection scope of the present invention with following embodiment.
Take by weighing the paraformaldehyde sample, be accurate to 0.0001g, place conical flask, add sodium hydroxide solution, add again superoxol to reacting completely, be cooled to room temperature, add the bromthymol blue indicator solution, be titrated to solution with the sulfuric acid standard titration solution and become blue-green.Do simultaneously blank test.Temperature of reaction is room temperature, need not heating water bath.
Paraformaldehyde content X% is calculated as follows:
X = ( V 0 - V ) C × 3.003 m × 100
In the formula:
The content of X-paraformaldehyde (in formaldehyde), %;
The concentration of C-sulfuric acid standard titration solution, mol/L;
The volume of the sulfuric acid standard titration solution that V-titration sample consumes, ml;
V 0The volume of the sulfuric acid standard titration solution that-titration blank consumes, ml;
3.003-with 1.00ml sulfuric acid standard titration solution (C(1/2H 2SO 4)=1mol/L) (quite to restrain the quality of the formaldehyde that represents, g;
The quality of m-sample, g.
Test philosophy:
Paraformaldehyde generates sodium formate with the superoxol reaction in excessive sodium hydroxide solution, and then instead drips excessive sodium hydroxide solution with the sulfuric acid standard titration solution.
Figure BDA00002386896500022
2NaOH+H ?2SO 4→Na 2SO 4+2H 2O
Detection example is as follows:
Example 1:
Take by weighing 0.6g paraformaldehyde sample, be accurate to 0.0001g, in the 250mL conical flask, accurately add 50.0mL Standard Volumetric Solutions for Sodium Hydroxide (C (NaOH))=1mol/L, add lentamente again 3% superoxol of the new preparation of 50ml, shake gently every now and then conical flask to reacting completely, be cooled to room temperature, leave standstill 10min, then add 6 bromthymol blue indicator solutions (10g/L), with sulfuric acid standard titration solution (C(1/2H 2SO 4)=1mol/L) is titrated to solution and becomes blue-green.Do simultaneously blank test.Record numerical value five times and be respectively 96.07%, 96.10%, 96.09%, 96.10%, 96.10%, mean value is 96.09, and the coefficient of variation is 0.04%.
Example 2:
Take by weighing 0.6g paraformaldehyde sample, be accurate to 0.0001g, in the 250mL conical flask, accurately add 50.0mL Standard Volumetric Solutions for Sodium Hydroxide (C (NaOH))=1mol/L, add lentamente again 3% superoxol of the new preparation of 50ml, shake gently every now and then conical flask to reacting completely heating water bath 5 minutes, be cooled to room temperature, leave standstill 10min, then add 6 bromthymol blue indicator solutions (10g/L), with sulfuric acid standard titration solution (C(1/2H 2SO 4)=1mol/L) is titrated to solution and becomes blue-green.Do simultaneously blank test.Record numerical value 2 times and be respectively 96.04%, 96.06%, mean value is 96.05%.
Example 3:
Take by weighing 0.6g paraformaldehyde sample, be accurate to 0.0001g, in the 250mL conical flask, accurately add 50.0mL Standard Volumetric Solutions for Sodium Hydroxide (C (NaOH))=1mol/L, add lentamente again 3% superoxol of the new preparation of 50ml, shake gently every now and then conical flask to reacting completely, heating water bath 10 minutes is cooled to room temperature, leaves standstill 10min, then add 6 bromthymol blue indicator solutions (10g/L), with sulfuric acid standard titration solution (C(1/2H 2SO 4)=1mol/L) is titrated to solution and becomes blue-green.Do simultaneously blank test.Record numerical value 2 times and be respectively 96.05%, 96.07%, mean value is 96.06%.
Example 4:
Take by weighing 0.6g paraformaldehyde sample, be accurate to 0.0001g, in the 250mL conical flask, accurately add 50.0mL Standard Volumetric Solutions for Sodium Hydroxide (C (NaOH))=1mol/L, add lentamente again 3% superoxol of the new preparation of 50ml, shake gently every now and then conical flask to reacting completely, heating water bath 20 minutes is cooled to room temperature, leaves standstill 10min, then add 6 bromthymol blue indicator solutions (10g/L), with sulfuric acid standard titration solution (C(1/2H 2SO 4)=1mol/L) is titrated to solution and becomes blue-green.Do simultaneously blank test.Record numerical value 2 times and be respectively 96.05%, 96.07%, mean value is 96.06%.

Claims (2)

1. the rapid assay methods of a paraformaldehyde content, it is characterized in that: step is as follows:
Take by weighing the paraformaldehyde sample, place container, add sodium hydroxide solution, add superoxol to reacting completely again, cooling adds the bromthymol blue indicator solution, and be titrated to solution with the sulfuric acid standard titration solution and become blue-green,
Paraformaldehyde content X% is calculated as follows:
X = ( V 0 - V ) C × 3.003 m × 100
In the formula:
The content of X-paraformaldehyde, in formaldehyde, %;
The concentration of C-sulfuric acid standard titration solution, mol/L;
The volume of the sulfuric acid standard titration solution that V-titration sample consumes, ml;
V 0The volume of the sulfuric acid standard titration solution that-titration blank consumes, ml;
3.003-with 1.00ml sulfuric acid standard titration solution C(1/2H 2SO 4)=1mol/L, g;
The quality of m-sample, g.
2. the rapid assay methods of paraformaldehyde content according to claim 1, it is characterized in that: temperature of reaction is room temperature.
CN 201210451696 2012-11-12 2012-11-12 Rapid paraformaldehyde content measuring method Pending CN102944554A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105445260A (en) * 2015-11-16 2016-03-30 渤海大学 Detection method for formaldehyde content in Spanish mackerel
CN109061042A (en) * 2018-08-16 2018-12-21 国家能源投资集团有限责任公司 A kind of method of unstable hydroxy radical content in measurement polyformaldehyde

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105445260A (en) * 2015-11-16 2016-03-30 渤海大学 Detection method for formaldehyde content in Spanish mackerel
CN105445260B (en) * 2015-11-16 2018-10-30 渤海大学 The detection method of content of formaldehyde in a kind of Spanish mackerel
CN109061042A (en) * 2018-08-16 2018-12-21 国家能源投资集团有限责任公司 A kind of method of unstable hydroxy radical content in measurement polyformaldehyde

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Application publication date: 20130227