CN104914214A - Generation method of formaldehyde - Google Patents
Generation method of formaldehyde Download PDFInfo
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- CN104914214A CN104914214A CN201510273629.8A CN201510273629A CN104914214A CN 104914214 A CN104914214 A CN 104914214A CN 201510273629 A CN201510273629 A CN 201510273629A CN 104914214 A CN104914214 A CN 104914214A
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Abstract
The invention discloses a generation method of formaldehyde. The generation method comprises following steps: firstly, 1 to 10<mu>l of a concentrated formaldehyde solution with a concentration of 36 to 40% is taken using a microsyringe, and is injected into a sealed first glass syringe which is filled with clean air purified with activated carbon columns; the first glass syringe is heated uniformly until complete volatilization of the formaldehyde solution injected into the first glass syringe is realized, and then the first glass syringe is cooled to room temperature; obtained gas containing formaldehyde in the first glass syringe is transferred into a second glass syringe and a third glass syringe successively, and obtained formaldehyde gas is subjected to standardization using a standard method and is taken as a formaldehyde stock gas; and then clean air purified with activated carbon columns is taken as a diluent, and standard formaldehyde gas of any concentration can be prepared via dilution. According to the generation method, standard formaldehyde gas of any concentration can be prepared, and the generation method is quite simple and reliable.
Description
Technical field
The present invention relates to a kind of generation method of formaldehyde, relate to a kind of compound method of standard formaldehyde gas in particular, belong to the preparing technical field of chemicals.
Background technology
Methylene oxide detecting instrument measures by relatively method, and normally first demarcate instrument with the formaldehyde gas of zero formaldehyde gas and a normal concentration, the typical curve obtained is stored among instrument.During mensuration, the electric signal that gas concentration to be measured produces by instrument compares with the electric signal of normal concentration, calculate formaldehyde gas concentration value accurately.Therefore, carry out school zero to instrument at any time, often demarcating instrument is all ensure that methylene oxide detecting instrument measures work required accurately.
Formaldehyde unstable chemcial property, soluble in water, be also easily polymerized, do not have formaldehyde sterling, this brings many difficulties to preparation formaldehyde standard gas.There is a kind of checker of formaldehyde sensor at present, this checker to blow with the trioxymethylene spreading generation in certain flow velocity just trioxymethylene anemostat with zero air after purification at a constant temperature and brings out, and is monomer formaldehyde through scribbling the quantitative thermal decomposition of glass microsphere catalysis post of phosphoric acid.Need trioxymethylene anemostat and supporting dynamic gas mixer could prepare the calibrating gas of desired concn during the compound method distribution of this formaldehyde standard gas.The diffusivity scope 2-50g/min of Formaldehyde diffusive tube, stable period is 6 months; Dynamic gas mixer has zero air and occurs and stability of flow, the constant temperature of anemostat and control, and the function such as Catalytic Thermal Decomposition post and gas and vapor permeation.Obviously, it is unpractical for adopting said method preparation formaldehyde standard gas to carry out demarcation to single or a small amount of methylene oxide detecting instrument.
Summary of the invention
In order to overcome the technological deficiency existed in above-mentioned prior art, the object of the present invention is to provide a kind of generation method of easy reliable formaldehyde.
In order to realize foregoing invention object, technical scheme of the present invention is as follows:
A generation method for formaldehyde, comprises the following steps:
A () draws with micro syringe the concentrated formaldehyde solution that 1 ~ 10 μ L concentration is 36% ~ 40%, concentrated formaldehyde solution is injected into one sealing and be full of with activated-charcoal column filter after pure air the first glass syringe in, this first glass syringe of homogeneous heating, formalin in implantation glass syringe is volatilized completely, is then cooled to room temperature;
B the gas containing formaldehyde in above-mentioned first glass syringe is transferred in the second glass syringe of the sealing of a clean dried by (), leave standstill 10 ~ 20 minutes, this second glass syringe is identical with described first glass syringe volume;
C the gas containing formaldehyde in above-mentioned second glass syringe is transferred in the 3rd glass syringe of the sealing of a clean dried by (), leave standstill 30 ~ 80 minutes, 3rd glass syringe is identical with described first glass syringe volume, and as found, the inwall of glass syringe has steam then to continue the gas containing formaldehyde in the 3rd glass syringe to be transferred in the glass syringe identical with the first glass syringe volume of the sealing of next clean dried;
D () is got after a certain amount of formaldehyde gas standard method after above-mentioned process is demarcated and is laid in gas as formaldehyde, then carry out diluting with the pure air after activated-charcoal column filters the standard formaldehyde gas being mixed with any concentration as thinning agent.
Wherein, the first described glass syringe volume is 60 ~ 90ml.
Wherein, in step (b), described time of repose is 60min.
Further, the first described glass syringe volume is 80ml.
Compared with prior art, the invention has the beneficial effects as follows:
The method of the invention makes the gas in syringe dry and content of formaldehyde remains unchanged within a certain period of time substantially, formaldehyde gas after transfer step process can be mixed with the standard formaldehyde gas of any concentration after the pure air dilution after filtering through activated-charcoal column, very reliably easy.
Embodiment
Below in conjunction with specific embodiment, further detailed description explanation is done to technical scheme of the present invention.
Adopt the distribution container of all-glass syringe as formaldehyde of clean dried, with micro syringe draw 1 ~ 10 μ L concentrated formaldehyde solution (36% ~ 40%) inject sealing and be full of with activated-charcoal column filter after pure air, nipple place elastomer seal 60 ~ 90mL glass syringe, room temperature is cooled to after the formaldehyde in implantation glass syringe being volatilized completely by the method for homogeneous heating glass syringe, now glass syringe inwall has one deck condensation vapor, this layer of steam can absorb the formaldehyde volatilized in the gas phase, makes it concentration and constantly reduces.The above-mentioned gas containing formaldehyde is transferred in the all-glass syringe of another same volume, clean dried, use elastomer seal at once, leaving standstill transfers them in the all-glass syringe of the 3rd same volume, clean dried, use elastomer seal again after 10 ~ 20 minutes, leave standstill after 30 ~ 80 minutes, as glass syringe inwall still has steam, then need to continue transfer, make the gas in syringe dry and content of formaldehyde remains unchanged within a certain period of time substantially.Get after appropriate formaldehyde gas one of following four kinds of analytical approachs after above-mentioned process are demarcated and can lay in gas as formaldehyde, then the pure air after filtering with activated-charcoal column can be mixed with the standard formaldehyde gas of variable concentrations as thinning agent.
1. diacetone spectrophotometric method, GB/T15516-1995 " air quality formaldehyde ground measures diacetone spectrophotometric method ";
2. phenol reagent method, GB/T18204.26 " public place method for determining formaldehyde in air ";
3.AHMT spectrophotometric method, GB/T16129 " residential district Formaldehyde in Atmosphere health test method spectrophotometric method ";
4. vapor-phase chromatography, GB/T18204.26 " public place method for determining formaldehyde in air ".
Embodiment
1. adopt the distribution container of 90mL all-glass syringe as formaldehyde of clean dried;
2. draw 5 μ L chemical pures with micro syringe or analyze that the pure concentrated formaldehyde solution (36% ~ 40%) of pure or top grade injects sealing and be full of the 90mL glass syringe of the pure air after filtering with activated-charcoal column, evenly blowing with hair dryer and be cooled to room temperature to volatilization completely;
3. the gas in syringe is proceeded to the same capacity of another dried and clean at once, in the glass syringe of sealing, also leave standstill 15 minutes;
4. again the dry formaldehyde gas in this syringe is proceeded to the same capacity of another dried and clean, in the glass syringe of sealing, also leave standstill 60 minutes;
5. get appropriate formaldehyde gas after above-mentioned process, carefully, absorbing liquid is injected lentamente, after demarcating its content of formaldehyde with phenol reagent method, this gas can lay in gas as formaldehyde, then the pure air after filtering with activated-charcoal column just can be mixed with the standard formaldehyde gas of variable concentrations as thinning agent.
It should be noted that, above preferred embodiment is used for illustrative purposes only, but not limitation of the present invention, person skilled in the relevant technique, without departing from the spirit and scope of the present invention, done various conversion or modification, all belong to category of the present invention.
Claims (4)
1. a generation method for formaldehyde, it is characterized in that, the method comprises the following steps:
A () draws with micro syringe the concentrated formaldehyde solution that 1 ~ 10 μ L concentration is 36% ~ 40%, concentrated formaldehyde solution is injected into one sealing and be full of with activated-charcoal column filter after pure air the first glass syringe in, this first glass syringe of homogeneous heating, formalin in implantation glass syringe is volatilized completely, is then cooled to room temperature;
B the gas containing formaldehyde in above-mentioned first glass syringe is transferred in the second glass syringe of the sealing of a clean dried by (), leave standstill 10 ~ 20 minutes, this second glass syringe is identical with described first glass syringe volume;
C the gas containing formaldehyde in above-mentioned second glass syringe is transferred in the 3rd glass syringe of the sealing of a clean dried by (), leave standstill 30 ~ 80 minutes, 3rd glass syringe is identical with described first glass syringe volume, and as found, the inwall of glass syringe has steam then to continue the gas containing formaldehyde in the 3rd glass syringe to be transferred in the glass syringe identical with the first glass syringe volume of the sealing of next clean dried;
D () is got after a certain amount of formaldehyde gas standard method after above-mentioned process is demarcated and is laid in gas as formaldehyde, then carry out diluting with the pure air after activated-charcoal column filters the standard formaldehyde gas being mixed with any concentration as thinning agent.
2. the compound method of a kind of formaldehyde standard gas according to claim 1, it is characterized in that, the first described glass syringe volume is 60 ~ 90ml.
3. the compound method of a kind of formaldehyde standard gas according to claim 1, it is characterized in that, in step (b), described time of repose is 60min.
4. the compound method of a kind of formaldehyde standard gas according to claim 2, it is characterized in that, the first described glass syringe volume is 80ml.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510273629.8A CN104914214A (en) | 2015-05-26 | 2015-05-26 | Generation method of formaldehyde |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201510273629.8A CN104914214A (en) | 2015-05-26 | 2015-05-26 | Generation method of formaldehyde |
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| CN104914214A true CN104914214A (en) | 2015-09-16 |
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| CN201510273629.8A Pending CN104914214A (en) | 2015-05-26 | 2015-05-26 | Generation method of formaldehyde |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1789975A (en) * | 2005-11-30 | 2006-06-21 | 上海电力学院 | Preparation method of formaldehyde standard gas |
| CN2929723Y (en) * | 2006-07-27 | 2007-08-01 | 中国计量科学研究院 | Dynamic gas distributor for multiple component expansion tube standard gases |
| CN103341330A (en) * | 2013-06-27 | 2013-10-09 | 江苏物联网研究发展中心 | Standard gas distribution device for gas testing system |
| CN103848731A (en) * | 2013-04-22 | 2014-06-11 | 襄阳泽东化工集团有限公司 | Formaldehyde production system |
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2015
- 2015-05-26 CN CN201510273629.8A patent/CN104914214A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1789975A (en) * | 2005-11-30 | 2006-06-21 | 上海电力学院 | Preparation method of formaldehyde standard gas |
| CN2929723Y (en) * | 2006-07-27 | 2007-08-01 | 中国计量科学研究院 | Dynamic gas distributor for multiple component expansion tube standard gases |
| CN103848731A (en) * | 2013-04-22 | 2014-06-11 | 襄阳泽东化工集团有限公司 | Formaldehyde production system |
| CN103341330A (en) * | 2013-06-27 | 2013-10-09 | 江苏物联网研究发展中心 | Standard gas distribution device for gas testing system |
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Application publication date: 20150916 |