CN106770245A - The assay method of cyanide content in aniline-acetonitrile product - Google Patents
The assay method of cyanide content in aniline-acetonitrile product Download PDFInfo
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- CN106770245A CN106770245A CN201611217483.6A CN201611217483A CN106770245A CN 106770245 A CN106770245 A CN 106770245A CN 201611217483 A CN201611217483 A CN 201611217483A CN 106770245 A CN106770245 A CN 106770245A
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Abstract
The present invention provides a kind of assay method of cyanide content in aniline-acetonitrile product, in pH=6, cyanide（CN‑）With mercuric nitrate (Hg（NO3）2) reaction generation mercury cyanide (Hg（CN）2), with thiomicoler's ketone, (4,4 ' is double（Dimethylamino）Thiobenzophenone) make indicator, mercuric nitrate standard titration solution titration, with the degree of accuracy higher, average recovery rate 88.55%, RSD（%）=6.79；And it is easy to operate, quick, reappearance preferably, can be used as the quality control method of cyanide content in aniline-acetonitrile product.
Description
Technical field
The present invention relates to the measure of cyanide content, and in particular to the survey of cyanide content in a kind of aniline-acetonitrile product
Determine method.
Background technology
Aniline-acetonitrile is a kind of important chemical intermediate, also can be used to prepare dyestuff, industrial general by hydroxyl second
Nitrile is obtained.Hydroxyacetonitrile is hydrogen cyanide and formaldehyde synthesis, thus may contain the complete cyanogen of unreacted in hydroxyacetonitrile product
Compound, while hydroxyacetonitrile is decomposed also produces cyanide.These cyanides enter aniline-acetonitrile in synthesizing anilino acetonitrile
Reaction solution, although the overwhelming majority of cyanide enters water phase when separating, it is possible that remaining on aniline-acetonitrile on a small quantity
In product.Current aniline-acetonitrile product does not have national standard and professional standard, and domestic aniline-acetonitrile manufacturing enterprise is not also right
Cyanide content in product is monitored.Cyanide severe toxicity, it is harmful.In order to ensure product quality, people group is ensured
Many health, control cyanide index is significant.
Current cyaniding object detecting method is more ripe, and disclosed documents and materials have chemical analysis (compleximetry, precipitation
Titration, oxidimetry), the chromatography of ions and AAS etc..As with p-dimethylaminobenzal rhodanine or KI as indicator
Silver nitrate titration method；With silver nitrate as precipitating reagent, ferriammonium sulfate is indicator, with the Fo Erhadefa that potassium rhodanide is titrant；
Iodimetric titration is used after being processed through bromine water；Separated with chromatography of ions anion column, pacify times detector detection method；Isonicotinic acid-pyrazolone
AAS, isonicotinic acid -- barbituric acid AAS, pyrideine-barbituric acid spectrophotometric method etc..
In presently disclosed data, the cyanide content assay method in aniline-acetonitrile product is not found.Due to aniline
Contain a small amount of hydroxyacetonitrile in base acetonitrile product, hydroxyacetonitrile has reproducibility, while hydroxyacetonitrile easily decomposes generation hydrogen cyanogen
Acid, the time is more long, temperature is higher, pH value is bigger, and hydroxyacetonitrile decomposes faster, so in above-mentioned determination methods of cyanide it is most not
The cyanide content that can be used in aniline-acetonitrile product is determined.If conventional p-dimethylaminobenzal rhodanine or KI are the silver nitrate of indicator
Titration, is carried out in the basic conditions, and p-dimethylaminobenzal rhodanine is given instruction agent pH value requirement more than 12, with this understanding hydroxyl in sample
Acetonitrile decomposes very fast, and hydrogen cyanide, interference measurement are produced after decomposition；With the oxidation-reduction method of iodometric determination, hydroxyl after bromine water treatment
Reducing substances has interference in the samples such as base acetonitrile；The chromatography of ions needs ion chromatograph, increased analysis cost, especially
Peace times detector is not also universal in manufacturing enterprise；Spectrophotometry sample needs to anticipate, hydroxyacetonitrile in treatment
Easily decompose very much, be currently used primarily in the environment point such as water analysis or the identification of soil, industrial wastewater, solid waste and hazardous waste
In analysis.The method for developing cyanide content in a kind of Accurate Determining aniline-acetonitrile product is very necessary.
The content of the invention
In order to solve the problems of the prior art, it is an object of the invention to provide cyaniding in a kind of aniline-acetonitrile product
The assay method of thing content, the method is easy to operate, quick, and preferably, accuracy is higher, can be produced as aniline-acetonitrile for reappearance
The quality control method of cyanide content index in product.
The object of the present invention is achieved like this：
The assay method of cyanide content in a kind of aniline-acetonitrile product, it is characterised in that:First aniline-acetonitrile is produced
Product sample is dissolved in ethanol, is added water, plus sodium acetate buffer solution, is shaken up, and adds thiomicoler's ketone indicator solution, uses mercuric nitrate
Standard titration solution is titrated to that solution is blue by orange discoloration, concentration, consumption according to the mercuric nitrate standard titration solution and
The consumption of the aniline-acetonitrile outturn sample can calculate the mass fraction of cyanide in the sample aniline-acetonitrile product.
Mercuric nitrate is with the reaction principle of cyanide：
2CN-+Hg(NO3)2→Hg(CN)2+2NO3 -
In pH=6, cyanide (CN-) and mercuric nitrate (Hg (NO3)2) reaction generation mercury cyanide (Hg (CN)2), with thio
Michaelis ketone (4,4 '-bis- (dimethylamino) thiobenzophenones) makees indicator, the titration of mercuric nitrate standard titration solution.
As further optimization, in above-mentioned aniline-acetonitrile product in the assay method of cyanide content, sample dissolution
Ethanol, addition is 5~15mL of every gram of sample plus ethanol.
As further optimizing, in above-mentioned aniline-acetonitrile product in the assay method of cyanide content, sample second
Added water after alcohol dissolving, addition is that every gram of sample adds water 70~100mL.
Specifically, in above-mentioned aniline-acetonitrile product cyanide content assay method, it is characterised in that using following step
Suddenly:
A certain amount of aniline-acetonitrile outturn sample is accurately weighed, adds 5~15mL of ethanol that sample is molten according to every gram of sample
Solution；Then added water 70~100mL according to every gram of sample, the shake of side edged, then add appropriate sodium acetate buffer solution, stir
Afterwards, thiomicoler's ketone indicator solution is added, solution is titrated to by orange discoloration blueness with mercuric nitrate standard titration solution, while doing
Blank test, the mass fraction w of cyanide (in terms of CN), is calculated as follows in the sample：
In formula,
C --- the exact value of mercuric nitrate standard titration solution concentration, unit is mole every liter (mol/L)；
V --- titration sample consumes the volumetric quantities of mercuric nitrate standard titration solution, and unit is milliliter (mL)；
V0--- the volumetric quantities of the mercuric nitrate standard titration solution that blank is consumed, unit is milliliter (mL)；
The mass figures of m --- test portion, unit is gram (g)；
26.02 --- by the numerical value of the molal weight of (in terms of CN), unit is gram every mole (g/mol) to cyanide.
The present invention uses in pH=6 (aniline-acetonitrile pH is 5~6), with thiomicoler's ketone as indicator, uses mercuric nitrate
Cyanide content in standard titration solution titration determination aniline-acetonitrile product.
In experiments it is found that, sample is exposed in atmosphere, and its cyanide content can have been reduced, and this is that hydrogen cyanide is gradually waved
Caused by hair effusion.To avoid the hydrogen cyanide in continuous mode in sample from volatilizing, note sealing remaining sample in operation, while
The sample for weighing is dissolved with ethanol immediately, dissolving is finished and added water immediately.Be also found in experiment, thio Michaelis is added in sample solution
If being titrated not in time after ketone indicator solution, titrated after placing 20 minutes, solution colour is not changed in, and rejoins indicator phenomenon
Normally.So, indicator should be added before titration is faced.
Beneficial effect：
The present invention provides a kind of assay method of cyanide content in aniline-acetonitrile product, in pH=6, cyanide
(CN-) and mercuric nitrate (Hg (NO3)2) reaction generation mercury cyanide (Hg (CN)2), with thiomicoler's ketone (4,4 '-bis- (dimethylaminos)
Thiobenzophenone) make indicator, the titration of mercuric nitrate standard titration solution；Survey the pH phases of time-controlled pH value and sample solution
Closely, and reaction speed is fast, analysis time is short, and the hydroxyacetonitrile in continuous mode in sample is not easily decomposed, and thiomicoler's ketone is made to refer to
Show agent, solution colour becomes blue by orange during titration end-point, and discoloration is sharp.The present invention has the degree of accuracy higher, average recovery rate
88.55%, RSD (%)=6.79, and it is easy to operate, quick, reappearance preferably, can be used as cyanide in aniline-acetonitrile product
The quality control method of content.
Specific embodiment
The present invention is specifically described below by specific embodiment, it is pointed out here that following examples are served only for this hair
It is bright to be further described, it is impossible to be interpreted as limiting the scope of the invention, the person skilled in the art of this area can be with root
Some nonessential modifications and adaptations are made to the present invention according to foregoing invention content.The all raw materials of the present invention and reagent are commercially available
Commodity.
Embodiment 1
The assay method of cyanide content in a kind of aniline-acetonitrile product, it is specifically followed the steps below：
(1) reagent preparation and solution
Salpeter solution：1+1.
500mL nitric acid is measured, 1000mL is diluted with water to.
Salpeter solution：1mol/L.
63mL nitric acid is measured, 1000mL is diluted with water to.
Sodium acetate buffer solution：PH=6 (presses GB/T 603-2002 preparations).
Mercuric nitrate standard titration solution：c〔1/2Hg(NO3)2)=0.02mol/L (with reference to GB/T4348.2-2014, uses c
〔1/2Hg(NO3)2Demarcated after the diluted silver nitrate of)=0.1mol/L).
Bromophenol blue indicator solution：1g/L.
Diphenyl carbazone indicator solution:5g/L ethanol solutions.
Thiomicoler's ketone indicator solution：0.1% acetone soln.
Thiomicoler's ketone 0.1g is weighed, with acetone solution and 100mL is diluted to, kept in dark place.Microburet 1mL.
(2) cyanide content in aniline-acetonitrile product is determined
Weigh 1g samples, claim accurate to 0.0002g, be placed in 250mL dries conical flask, adds 10mL ethanol to make it immediately
It is completely dissolved, is slowly added into 100mL water, the shake of side edged.10mL sodium acetate buffer solutions (pH=6) is added, is shaken up.Add 4
~5 drop thiomicoler's ketone indicator solutions, with mercuric nitrate standard titration solution (c (1/2Hg (NO3)2)=0.02mol/L) be titrated to it is molten
Liquid is blue by orange discoloration, while entering line blank test.
The mass fraction w of cyanide (in terms of CN) in aniline-acetonitrile product is calculated finally according to following formula,
In formula,
C --- the exact value of mercuric nitrate standard titration solution concentration, unit is mole every liter (mol/L)；
V --- titration sample consumes the volumetric quantities of mercuric nitrate standard titration solution, and unit is milliliter (mL)；
V0--- the volumetric quantities of the mercuric nitrate standard titration solution that blank is consumed, unit is milliliter (mL)；
The mass figures of m --- test portion, unit is gram (g)；
26.02 --- by the numerical value of the molal weight of (in terms of CN), unit is gram every mole (g/mol) to cyanide.
The preparation method of sample solution is also examined in experiment, and has carried out Method validation.
It is prepared by sample solution
Solubility of the aniline-acetonitrile in water is small, and solubility is big in ethanol.The experiment ethanol of 5mL, 10mL, 15mL
Dissolving 1g samples, wherein, can be completely dissolved for 1g samples in about 30s by 10mL ethanol, and 5mL ethanol is in 2~3min dissolving 1g examinations
Sample.Consider, it is determined that with 10mL ethanol dissolved samples.
After sample is dissolved by ethanol, slowly add water, the shake of side edged.Increase with rate of water added, aniline-acetonitrile is gradually analysed
Go out, make solution turned cloudy.Continue to add water to more than 70mL, solid-liquid is initially separated, cyanide enters water phase, water is more big easier point
From.In view of the observation for being easy to titration end-point after separation of solid and liquid, allow also for easy to operate, the addition for determining water is
100mL。
If added water rapidly after the dissolving of sample ethanol, relatively stable suspension is formed, solid-liquid is not readily separated, influence drop
Determine the observation and judgement of terminal.So determining：After sample is dissolved with 10mL ethanol, 100mL water, the shake of side edged are slowly added into.
The actual sample of embodiment 2 is determined
It is 201612057 aniline-acetonitrile sample 1.0162g to weigh numbering, as described in Example 1, (1/ with concentration as c
2Hg(NO3)2The mercuric nitrate standard titration solution of)=0.02001mol/L is titrated to terminal, quota of expenditure volumetric soiutions
0.301mL, blank is 0.000mL.
The mass fraction w of cyanide (in terms of CN), is calculated as follows in sample：
The actual sample of embodiment 3 is determined
It is 201612058 aniline-acetonitrile sample 1.1274g to weigh numbering, is dissolved with 15mL ethanol, by the side of embodiment 1
Method, the (1/2Hg (NO with concentration as c3)2The mercuric nitrate standard titration solution of)=0.02001mol/L is titrated to terminal, quota of expenditure
Volumetric soiutions 0.320mL, blank is 0.000mL.
The mass fraction w of cyanide (in terms of CN), is calculated as follows in sample：
The actual sample of embodiment 4 is determined
It is 201612059 aniline-acetonitrile sample 1.1050g to weigh numbering, and after being dissolved with 10mL ethanol, add water 70mL, its
It as described in Example 1, the (1/2Hg (NO with concentration as c3)2The mercuric nitrate standard titration solution titration of)=0.02001mol/L
To terminal, quota of expenditure volumetric soiutions 0.318mL, blank is 0.000mL.
The mass fraction w of sample cyanide (in terms of CN), is calculated as follows：
Embodiment 5 (replica test)
It is test specimen with the aniline-acetonitrile sample that numbering is 201612015, is well mixed, weigh 1g, claims standard extremely
0.0002g, as described in Example 1, the (1/2Hg (NO with concentration as c3)2)=0.02001mol/L mercuric nitrate standard titration solutions
Determine cyanide content.Repetition weighs same batch of sample determination and (claims sample to finish the sealing of remaining sample every time, it is to avoid surveying 5 times
Hydrogen cyanide volatilization during fixed).Cyanide content in sample is calculated, 1 is the results are shown in Table.
The replica test result of table 1
Average content 0.0141%：RSD (%)=4.28.
Embodiment 6 (accuracy validation --- recovery testu)
(1) solution is prepared
Saturated solution of potassium iodide.
Ammoniacal liquor (2+3)：Ammoniacal liquor 100mL is measured, is diluted with 150mL.
Mercuric nitrate standard titration solution c (1/2Hg (NO3)2)=0.02mol/L is (with reference to GB/T4348.2-2014, with c (1/
2Hg(NO3)2Demarcated after the diluted silver nitrate of)=0.1mol/L).
Silver nitrate standard titration solution c (AgNO3)=0.02mol/L (is prepared) according to GB/T 601-2002.
Cyanide (CN) standard liquid：C (CN)=0.1mg/mL.
Prepare：The solid sodium cyanide about 0.19g that content is 99.0% is weighed, 100mL is dissolved in water and is diluted to, mixed.
Take 25mL and be diluted with water to 250mL, shake up.
Demarcate：Above-mentioned solution 100mL is accurately drawn in conical flask, plus 10mL ammonia spirits (2+3), plus 10 and drip KI
Saturated solution, micro- muddy, the quota of expenditure volumetric soiutions that are titrated to solution with the silver nitrate standard titration solution of 0.01995mol/L
9.20mL。
Calculate:Cyanide concentration of standard solution (mg/mL), is calculated as follows：
In formula,
V --- the silver nitrate standard titration solution volumetric quantities of titration consumption, unit is milliliter (mL)；
C --- the exact value of silver nitrate standard titration solution concentration, unit is mole every liter (mol/L)；
26.02 --- the numerical value of the molal weight of cyanide (in terms of (CN)), unit is gram every mole (g/mol)；
100 --- the volumetric quantities of the cyanide solution of absorption, unit is milliliter (mL).
Sodium acetate buffer solution：PH=6.
Thiomicoler's ketone indicator solution：0.1% acetone soln.
(2) recovery experiment step
With number be 201612015 aniline-acetonitrile sample be test specimen (containing cyanide in terms of CN：0.0141%),
Accuracy validation is carried out with sample-adding absorption method.
Weigh sample 0.5g, claim accurate to 0.0002g, be placed in 250mL dries conical flask, then it is accurate add c (CN)=
The cyanide standard liquid 0.40mL of 0.09552mg/mL, determines and calculates cyaniding amount of substance, in repetition as described in Example 1
Experiment is stated, but cyanide standard liquid addition is respectively 0.80mL, 1.20mL (note：Sample is claimed to finish every time remaining sample is close
Envelope, it is to avoid the hydrogen cyanide volatilization in continuous mode), the rate of recovery is calculated, measurement result is shown in Table 2.
Table 2 is loaded recovery test result
Average recovery rate 88.55%, RSD (%)=6.79.
Test result indicate that, in pH=6, being titrated with mercuric nitrate standard titration solution, thiomicoler's ketone indicates titration eventually
Point, determines cyanide content in aniline-acetonitrile product, with the degree of accuracy higher and easy to operate, quick, reappearance compared with
It is good.Can be used as the quality control method of cyanide content in aniline-acetonitrile product.
Claims (4)
1. in a kind of aniline-acetonitrile product cyanide content assay method, it is characterised in that:First by aniline-acetonitrile product
Sample is dissolved in ethanol, is added water, plus sodium acetate buffer solution, is shaken up, and adds thiomicoler's ketone indicator solution, uses mercuric nitrate mark
Quasi- volumetric soiutions are titrated to solution by orange discoloration blueness, concentration, consumption and institute according to the mercuric nitrate standard titration solution
The mass fraction of cyanide in the sample aniline-acetonitrile product is calculated by the consumption for stating aniline-acetonitrile outturn sample.
2. method as claimed in claim 1, it is characterised in that：Every gram of sample adds 5~15mL of ethanol.
3. method as claimed in claim 1 or 2, it is characterised in that：Every gram of sample adds 70~100mL of water.
4. method as claimed in claim 3, it is characterised in that use following steps:
A certain amount of aniline-acetonitrile sample is accurately weighed, adds 5~15mL of ethanol to dissolve sample according to every gram of sample；Then press
Added water 70~100mL according to every gram of sample, the shake of side edged；Again plus sodium acetate buffer solution, after stirring, thio rice is added
Family name's ketone indicator solution, is titrated to solution by orange discoloration blueness, while doing blank test with mercuric nitrate standard titration solution；The sample
The mass fraction w of cyanide (in terms of CN), is calculated as follows in product：
In formula,
C --- the exact value of mercuric nitrate standard titration solution concentration, unit is mole every liter (mol/L)；
V --- titration sample consumes the volumetric quantities of mercuric nitrate standard titration solution, and unit is milliliter (mL)；
V0--- the volumetric quantities of the mercuric nitrate standard titration solution that blank is consumed, unit is milliliter (mL)；
The mass figures of m --- test portion, unit is gram (g)；
26.02 --- by the numerical value of the molal weight of (in terms of CN), unit is gram every mole (g/mol) to cyanide.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044507A (en) * | 2019-12-10 | 2020-04-21 | 浙江新一检测科技有限公司 | Method for measuring cyanide and hydrogen cyanide in workplace |
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2016
- 2016-12-26 CN CN201611217483.6A patent/CN106770245A/en active Pending
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| Title |
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| 化学分析/杭州大学化学系分析化学教研室编: "其他络合滴定测定法", 《分析化学手册第二分册》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111044507A (en) * | 2019-12-10 | 2020-04-21 | 浙江新一检测科技有限公司 | Method for measuring cyanide and hydrogen cyanide in workplace |
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