CN104360008B - Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system - Google Patents
Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system Download PDFInfo
- Publication number
- CN104360008B CN104360008B CN201410619104.0A CN201410619104A CN104360008B CN 104360008 B CN104360008 B CN 104360008B CN 201410619104 A CN201410619104 A CN 201410619104A CN 104360008 B CN104360008 B CN 104360008B
- Authority
- CN
- China
- Prior art keywords
- iodine
- concentration
- cyclic carbonate
- solution
- sample
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
Abstract
The invention discloses a detection method for the concentration of iodine in a polyethylene glycol-potassium iodide-cyclic carbonate mixed system and aims at providing a method which is applicable to measurement for the concentration of the iodine in a crude cyclic carbonate product in the production process of synthesizing cyclic carbonate by adopting a polyethylene glycol-potassium iodide system as a catalyst. With the adoption of the method, the problems of lower analysis result and extremely-poor repeatability caused by coating of the polyethylene glycol on the iodine are effectively solved, and the accuracy and the repeatability of iodine-concentration analysis are improved. The detection method comprises the specific steps: (1) accurately weighing 5-8g of a sample in a 250mL iodine flask, adding 10mL of corresponding cyclic carbonate, and after oscillating and dissolving the sample to be detected, adding 50mL of distilled water; (2) adding an excessive oxidizing agent, shaking to be uniform and standing for 1 minute; (3) adding excessive oxalic acid and heating; (4) adding an acidic reagent for acidification and carrying out iodine amplifying treatment; (5) carrying out titration; and (6) calculating the concentration of iodine ions in the obtained solution.
Description
Technical field
The present invention relates to the detection method of a kind of iodine concentration, particularly to PEG-I potassium-cyclic carbonate mixing
The detection method of iodine concentration in system.
Background technology
Allyl carbonate and ethylene carbonate are the cyclic carbonates being most widely used, be mainly used in plastics, printing and dyeing,
The field such as Polymer Synthesizing, battery electrolyte, is also synthesis of dimethyl carbonate via transesterification and the raw material of third (second) glycol.Mesh
Before, in the technique of commercial synthesis Allyl carbonate and ethylene carbonate, the main catalyst used is to be with alkali metal salt at home
The complex compound catalyst of active component, the catalyst being wherein commonly used is potassium iodide-Polyethylene Glycol complex.But, urge
Agent potassium iodide-Polyethylene Glycol complex is formed a kind of with potassium iodide-Polyethylene Glycol-ring-type during synthesizing annular carbonate
Carbonic ester is the mixed system of main body, and this system has higher viscosity, and its viscosity is along with entering that synthesizing annular carbonate reacts
Row constantly increases, and iodide ion concentration is gradually dropped to 0.15% by 0.9%, the most aging forfeiture in active center, thereby results in ring-type carbon
The synthesis efficiency of acid esters is low, and product quality deteriorates.Therefore the activity for this System Catalyst of management and control is found a kind of quick
Detection method is imperative.
The method having the Iodine assay that document reports at present has: under strongly acidic conditions,Generate after oxidizedWith
ExcessReaction generates, the step amplifying method making iodine in original solution increase by 500 measures the micro iodine in aqueous solution；GB GB/
T 13025.7 1999 has a kind of direct titrimetric method, two kinds of oxidation-reduction methodes and a kind of photometry, wherein hypochlorite oxidation
Reduction rule is the arbitration law of national regulations.But do not have a kind of in the organic mixture of certain viscosity complicated components iodine dense
The assay method of degree.
Summary of the invention
It is an object of the invention to provide one to be applicable to PEG-I potassium system for catalyst synthesis of cyclic carbonic acid
Iodine concentration method for measuring in cyclic carbonate crude product in the production process of ester, effectively solves to make because of polyethylene glycol coated iodine
Become to analyze Lower result and the problem of repeatability extreme difference, improve accuracy and repeatability that iodine concentration is analyzed.
The detection method of iodine concentration in the present invention a kind of PEG-I potassium-cyclic carbonate mixed system, under employing
State step to be achieved: (1). sampling and the pre-treatment of sample: accurately weigh 5～8g testing samples in 250mL iodine flask, add
After entering 10mL corresponding cyclic carbonate concussion sample dissolution, add 50mL distilled water；(2). in above-mentioned solution, add excess
The oxidizing agent sodium hypochlorite that effective chlorine density concentration is 2.20%～3.00%, and shake up standing 1min；(3). in step (2)
Solution in add the reducing agent oxalic acid that amount concentration is 0.38-0.60mol/L of excess material, and reacting by heating 3～5min；
(4). add acid reagent and be acidified and carry out iodine processing and amplifying: adding 1mL mass concentration in above-mentioned solution is 9.5%～10%
Any one acid reagent in sulphuric acid or phosphoric acid shakes up, and adding 10mL mass concentration is that 5.0% potassium iodide standard solution shakes up,
Stand 3min in dark place after fluid-tight；(5). titration: be that 0.45%～0.55% amidin is as End point indication using mass concentration
Liquid, titrates the iodine amplified by above-mentioned solution, according to end with the sodium thiosulfate standard solution that substance withdrawl syndrome is 0.1mol/L
Point indicator solution judges titration end-point, and writes down the volume V that sodium thiosulfate standard solution is consumed；(6). use formulaCalculate the iodide ion concentration in solution, wherein:
V consumes the volume of the standard reagent b of reproducibility when representing titration end-point, unit is mL；
C represents the substance withdrawl syndrome of the standard reagent b of reproducibility, and unit is mol/L；
M is the quality of testing sample, and unit is g；
21.15 × 10-3 be 1mL sodium thiosulfate standard solution (1.0mol/L) be equivalent to the iodine of 21.15 × 10-3g from
Son.
In technique scheme, selected detection method be applicable to the mean molecule quantity of Polyethylene Glycol be 200～600 former
Material.
Technique scheme, the cyclic carbonate related in step (1) is any in ethylene carbonate, Allyl carbonate
A kind of.And add distilled water concussion extraction process.Allyl carbonate or ethylene carbonate can dissolved dilution Polyethylene Glycol, distilled water
The iodide ion in organic solution can be extracted, efficiently solve and cause analysis result on the low side because of polyethylene glycol coated iodine and repeat
The problem of property extreme difference.
Technique scheme, in step (2), sodium hypochlorite is the oxidant that a kind of oxidation susceptibility is moderate, it can effectively by
In solution, iodide ion is oxidized to iodate.The prediction of content of iodine during wherein the concrete addition of liquor natrii hypochloritis regards testing sample
Value is for reference: especially, and when the iodine number in 8g sample is less than 0.08g, liquor natrii hypochloritis's addition is 4mL, when 8g sample
In iodine number more than 0.08g and less than 0.16g time, liquor natrii hypochloritis's addition is 8mL.
Technique scheme, in step (3), excess oxalic acid can be with the sodium hypochlorite of removing step (2) reaction excess.And add
Thermal response 3～5min is to get rid of the excessive reducing agent oxalic acid adverse effect to follow-up titration.
As the preferred technical solution of the present invention, the substance withdrawl syndrome of oxalic acid is 0.50mol/L.
Technique scheme, the acid reagent added in step (4) be mass concentration be sulphuric acid and the phosphoric acid of 9.5%～10%
In any one, and be excellent with phosphoric acid, it can shield the interference of other metal ions；The quality of potassium iodide standard solution is dense
Degree is 5.0%, and potassium iodide standard solution is used to the propiodal enriched the iodine, and iodate can be oxidized to elemental iodine by it.
Technique scheme, in step (5), elemental iodine can be reduced into iodide ion by sodium thiosulfate in an acidic solution；
Select End point indication liquid be its mass concentration of amidin be 0.45%～0.55%, it can indicate that judge iodine titrated and also
Terminal time former.With sodium thiosulfate standard solution volumetric soiutions to faint yellow during titration, become after adding 1～2mL starch indicator solution
For blueness, till continuing to be titrated to when blueness is just decorporated, write down the volume V consuming sodium thiosulfate standard solution；
In sum, the present invention is to be oxidizing iodide ion with sodium hypochlorite, by quantitatively mending in above-mentioned system
Iodine amplifies, and uses the method for sodium thiosulfate standard solution reductometry to measure PEG-I potassium-cyclic carbonate
Iodine concentration in mixed system.The activity producing management and control catalyst for cyclic carbonate provides the one side of detection fast and effectively
Method, has the effect that and can effectively measure the catalyst in synthesizing annular carbonate production process and cyclic carbonate crude product
In iodine concentration, analysis result accuracy and reproducible, parallel determinations error≤0.02%；Naked vision pair by people
The restriction that solution colour distinguishes, the iodide ion detection limit of the present invention is less than 0.05%, it is possible to meets production well and is actually needed,
Solve the problem causing analysis result extreme difference on the low side and repeated because of polyethylene glycol coated iodine.
Detailed description of the invention
Below in conjunction with detailed description of the invention, the present invention will be further described:
Embodiment one:
(1) sampling and the pre-treatment of sample: from rectification tower reactor or the charging aperture of the Allyl carbonate of iodide ion concentration to be measured
Sampling, seals and is cooled to room temperature, and stirring and evenly mixing also accurately weighs 5.89g in 250mL iodine flask, addition 10mL Allyl carbonate
(purity >=99.5%), concussion is dissolved, and adds 50mL distilled water and shakes 1 minute, static extraction iodide ion.
(2) in above-mentioned solution, add the liquor natrii hypochloritis 4mL that excess of chloride ion concentration is 2.35%, shake up standing
1min。
(3) the amount concentration adding excess material in the solution in step (2) is 0.50mol/L oxalic acid solution 5mL, shakes
Even, it is heated under liquid level having bubble to produce (reacting by heating 3～5min) with electric furnace, gentle agitation.
(4) add acid reagent and be acidified and carry out iodine processing and amplifying: adding 1mL mass concentration in above-mentioned solution is 9.5%
Phosphoric acid,diluted, shake up, add mass concentration be 5.0% potassium iodide standard solution 10mL, shake up, fluid-tight, dark place stand 3min.
(5) titration: with sodium thiosulfate standard solution (C=0.1013mol/L) volumetric soiutions to the most faint yellow, add 1～
2mL mass concentration is to become blue after 0.45%～0.55% starch indicator solution, till continuing to be titrated to when blueness is just decorporated, and note
The volume V=13.90mL of lower consumption sodium thiosulfate standard solution.
(6) formula calculates iodine concentration: by above-mentioned M=5.89g, V=13.90mL, C=0.1013mol/L substitute into formula, be calculated mass concentration=2.115 × 13.90 of the iodine of this sample ×
0.1013/5.89(%)=0.506%.Parallel assay twice, resultant error 0.011%.
Embodiment two:
(1) sampling and the pre-treatment of sample: from rectification tower reactor or the charging aperture of the Allyl carbonate of iodide ion concentration to be measured
Sampling, seals and is cooled to room temperature, and stirring and evenly mixing also accurately weighs 6.15g in 250mL iodine flask, addition 10mL Allyl carbonate
(purity >=99.5%), concussion is dissolved, and adds 50mL distilled water and shakes 1 minute, static extraction iodide ion.
(2) in above-mentioned solution, add the liquor natrii hypochloritis 4mL of excess of chloride ion concentration 2.35%, shake up standing 1min.
(3) the amount concentration adding excess material in the solution in step (2) is 0.50mol/L oxalic acid solution 5mL, shakes
Even, it is heated under liquid level having bubble to produce (reacting by heating 3～5min) with electric furnace, gentle agitation.
(4) add acid reagent and be acidified and carry out iodine processing and amplifying: adding 1mL mass concentration in above-mentioned solution is 10%
Phosphoric acid,diluted, shake up, add iodide ion mass concentration be 5.0% potassium iodide standard solution 10mL, shake up, fluid-tight, dark place stand
3min。
(5) titration: with sodium thiosulfate standard solution (C=0.1013mol/L) volumetric soiutions to the most faint yellow, add 1～
2mL mass concentration is to become blue after 0.45%～0.55% starch indicator solution, till continuing to be titrated to when blueness is just decorporated, and note
The volume V=48.70mL of lower consumption sodium thiosulfate standard solution.
(6) formula calculates iodine concentration: by above-mentioned M=6.15g, V=48.70mL, C=0.1013mol/L substitute into formula, be calculated mass concentration=2.115 × 48.70 of the iodine of this sample ×
0.1013/6.15(%)=1.697%.Prediction concentrations is more than 1%, by this method, liquor natrii hypochloritis's amount that above-mentioned steps (2) uses
Should be 8mL, it is thus desirable to redeterminate by above-mentioned steps.Except for the difference that liquor natrii hypochloritis's addition is 8mL, M=6.17g, V=
54.45mL, is calculated the mass concentration=2.115 × 54.45 × 0.1013/6.17(% of the iodine of this sample)=1.891%, parallel
Measure twice, resultant error 0.006%.
Embodiment three:
(1) sampling and the pre-treatment of sample: from rectification tower reactor or the charging aperture of the Allyl carbonate of iodide ion concentration to be measured
Sampling, seals and is cooled to room temperature, and stirring and evenly mixing also accurately weighs 6.03g in 250mL iodine flask, addition 10mL Allyl carbonate
(purity >=99.5%), concussion is dissolved, and adds 50mL distilled water and shakes 1 minute, static extraction iodide ion.
(2) adding excess of chloride ion concentration in above-mentioned solution is 2.35% liquor natrii hypochloritis 4mL, shakes up standing 1min.
(3) the amount concentration adding excess material in the solution in step (2) is 0.50mol/L oxalic acid solution 5mL, shakes
Even, it is heated under liquid level having bubble to produce (reacting by heating 3～5min) with electric furnace, gentle agitation.
(4) add acid reagent and be acidified and carry out iodine processing and amplifying: adding mass concentration in above-mentioned solution is 9.8%
Phosphoric acid,diluted 1mL, shakes up, and adds 10mL potassium iodide standard solution (iodide ion mass concentration is 5.0%), shakes up, fluid-tight, and dark place is quiet
Put 3min.
(5) titration: with sodium thiosulfate standard solution (C=0.1032mol/L) volumetric soiutions to the most faint yellow, add 1～
2mL mass concentration is to become blue after 0.45%～0.55% starch indicator solution, till continuing to be titrated to when blueness is just decorporated, and note
The volume V=6.85mL of lower consumption sodium thiosulfate standard solution.
(6) formula calculates iodine concentration: by above-mentioned M=6.03g, V=6.85mL, C=0.1032mol/L substitute into formula, be calculated mass concentration=2.115 × 6.85 of the iodine of this sample ×
0.1032/6.03(%)=0.248%.Parallel assay twice, resultant error 0.013%.
Claims (4)
1. the detection method of iodine concentration in PEG-I potassium-cyclic carbonate mixed system, it is characterised in that use
Following steps:
Step is (1). sampling and the pre-treatment of sample: accurately weigh 5～8g samples in 250mL iodine flask, add 10mL corresponding
After cyclic carbonate concussion sample dissolution, add 50mL distilled water；
Step is (2). in above-mentioned solution, add the oxidizing agent sodium hypochlorite that effective chlorine density is 2.20%～3.00% of excess, and
Shake up standing 1min；
Step is (3). the solution in step (2) adds the reducing agent that amount concentration the is 0.38-0.60mol/L grass of excess material
Acid 5-7mL, and reacting by heating 3～5min；
Step is (4). and add acid reagent and be acidified and carry out iodine processing and amplifying: adding 1mL mass concentration in above-mentioned solution is 9.5%
～any one acid reagent in the sulphuric acid of 10% or phosphoric acid shakes up, adding 10mL mass concentration is that 5.0% potassium iodide standard is molten
Liquid shakes up, and stands 3min after fluid-tight in dark place；
Step is (5). titration: using mass concentration be 0.45%～0.55% amidin as End point indication liquid, dense by the amount of material
Degree is that the sodium thiosulfate standard solution of 0.10 ± 0.005mol/L titrates the iodine amplified by above-mentioned solution, according to End point indication liquid
Judge titration end-point, and write down the volume V that sodium thiosulfate standard solution is consumed；
Step (6). use formulaCalculate the iodide ion concentration in solution, wherein:
V consumes the volume of the standard reagent sodium thiosulfate of reproducibility when representing titration end-point, unit is mL；
C represents the substance withdrawl syndrome of the standard reagent sodium thiosulfate of reproducibility, and unit is mol/L；
M is the quality of testing sample, and unit is g；
21.15×10-3It is that 1mL sodium thiosulfate standard solution (1.0mol/L) is equivalent to 21.15 × 10-3The iodide ion of g.
The detection of iodine concentration in a kind of PEG-I potassium-cyclic carbonate mixed system the most according to claim 1
Method, it is characterised in that: the cyclic carbonate in described step (1) is any one in ethylene carbonate, Allyl carbonate.
The detection of iodine concentration in a kind of PEG-I potassium-cyclic carbonate mixed system the most according to claim 1
Method, it is characterised in that: the addition of oxidizing agent sodium hypochlorite is as follows, when the iodine number in 8g sample is less than 0.08g, hypochlorous acid
Sodium solution addition is 4mL, and when the iodine number in 8g sample is less than 0.16g more than 0.08g, liquor natrii hypochloritis's addition is
8mL。
The detection of iodine concentration in a kind of PEG-I potassium-cyclic carbonate mixed system the most according to claim 1
Method, it is characterised in that: the substance withdrawl syndrome of described oxalic acid is 0.50mol/L.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410619104.0A CN104360008B (en) | 2014-11-07 | 2014-11-07 | Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410619104.0A CN104360008B (en) | 2014-11-07 | 2014-11-07 | Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104360008A CN104360008A (en) | 2015-02-18 |
| CN104360008B true CN104360008B (en) | 2017-01-11 |
Family
ID=52527289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410619104.0A Active CN104360008B (en) | 2014-11-07 | 2014-11-07 | Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104360008B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110554034A (en) * | 2019-09-23 | 2019-12-10 | 江西理工大学 | Reagent for detecting content of polyethylene glycol in copper electroplating acid solution and detection method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101003531A (en) * | 2006-07-25 | 2007-07-25 | 南开大学 | Method for preparing cyclic carbonate by using catalysis of periodic usable functional polyglycol |
| CN102507568A (en) * | 2011-10-09 | 2012-06-20 | 东北制药集团股份有限公司 | Method for detecting content of cis-propenyl phophonic acid in phosphate-ammonium salt |
-
2014
- 2014-11-07 CN CN201410619104.0A patent/CN104360008B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101003531A (en) * | 2006-07-25 | 2007-07-25 | 南开大学 | Method for preparing cyclic carbonate by using catalysis of periodic usable functional polyglycol |
| CN102507568A (en) * | 2011-10-09 | 2012-06-20 | 东北制药集团股份有限公司 | Method for detecting content of cis-propenyl phophonic acid in phosphate-ammonium salt |
Non-Patent Citations (1)
| Title |
|---|
| 碘-聚乙烯醇显色法标定硫代硫酸钠溶液;薛笑莉;《化学分析计算》;20031231;第12卷(第4期);第40-41页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104360008A (en) | 2015-02-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106404995B (en) | A kind of method that constant-current titration measures chlorine, full content of vanadium and Vanadium valence in mixed acid electrolyte | |
| CN103760051B (en) | Method for measuring content of silicon and zirconium in silicon-zirconium alloy | |
| CN103499577B (en) | The assay method of hydrogen cyanide and chloride ion content in a kind of sample | |
| CN106290334B (en) | The chemistry in detecting of cobalt and manganese content in cobalt manganese raw material | |
| CN106248862B (en) | A kind of chloride ion conductor method in polycarboxylate water-reducer | |
| CN104458731A (en) | Method for joint measurement of calcium-barium content of silicon-barium alloy by using compleximetry | |
| CN102539426A (en) | Method for determining phosphorus in silicon-manganese alloy | |
| CN108152444A (en) | Method for detecting content of free nitric acid in bismuth nitrate solution | |
| CN102539511A (en) | Method for detecting content of bromine in fire retardant through automatic potentiometric titration | |
| CN109633079A (en) | A method of vanadium and ammonium content in detection metavanadate solution | |
| CN109142620A (en) | Recycle the analysis method of calcium sulfate in calcirm-fluoride | |
| CN106404998B (en) | The detection method of Theil indices in a kind of high concentration of hydrogen tin oxide products | |
| CN111443085A (en) | Method for rapidly detecting content of water-soluble chloride in feed | |
| CN104360008B (en) | Detection method for concentration of iodine in polyethylene glycol-potassium iodide-cyclic carbonate mixed system | |
| CN109061041A (en) | The measuring method of the COD of waste water | |
| CN104330521A (en) | Method for determining content of calcium oxide in raw and auxiliary metallurgical materials | |
| CN110161176A (en) | A kind of COD rapid detection method of production waste water with high salt | |
| CN102590317B (en) | PH composite electrode method for measuring content of nitrite ions in solution | |
| CN103823017A (en) | Method for accurate measurement on nitric acid content of chemical corrosion solution for titanium alloy | |
| CN102608280B (en) | Stabilizer for measuring content of total sugar and reducing sugar by direct titration method and preparation method of stabilizer | |
| CN113237994A (en) | Method for rapidly analyzing and detecting impurity sodium sulfide in barium sulfide solution | |
| CN105548460A (en) | Method for measuring tin oxide content | |
| CN110850025A (en) | Method for determining chloride ion content in industrial iron oxide by automatic potentiometric titration | |
| CN110702847A (en) | Method for quickly measuring sulfate radical content of vanadium battery electrolyte through temperature titration | |
| CN104062337B (en) | A kind of graphite electrode and the method measuring chloride ion content in copper sulphate thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |