Chemical reagent

Definitionofchemicalreagents

Chemicalreagentshavebeenwidelyusedinindustry,agriculture,medicalandhealth,lifesciences,inspectionandquarantine,environmentalprotection,energydevelopment,nationaldefenseandmilitaryindustry,Scientificresearchandallwalksoflifeinthenationaleconomy,butwhatisa"chemicalreagent",whatcontentitcontains,anditisstillaverydifficultthingtogiveitanaccuratedefinition.Earlychemicalreagentsonlyreferto"purechemicalsusedtodeterminethecompositionorcompositionofsubstancesinchemicalanalysisandchemicaltests."Itwaslaterexpandedto"chemicalsusedtoachievechemicalreactions",andthechemicalsreferredtoby"chemicalreagents"havelonggonebeyondthiscategory.Somepeoplethinkthat"chemicalsusedinscientificexperiments"canbecalled"chemicalreagents."Amorecomprehensivedefinitionofchemicalreagentscanbe:compoundsorelementsofvariouspuritylevelsusedinchemicaltests,chemicalanalysis,chemicalresearchandothertests.

Currentnationalstandards

GB/T14305-1993chemicalreagentcyclohexane

GB15346-1994chemicalreagentpackagingandmarking

GB/T15347-1994chemicalreagentascorbicacid

GB/T15895-1995chemicalreagent1,2-dichloroethane

GB/T15896-1995chemicalreagentformicacid

GB/T15897-1995chemicalreagentcalciumcarbonate

GB/T15898-1995chemicalreagentcobaltnitratehexahydrate(cobaltnitrate)

GB/T15899-1995Chemicalreagentmanganesesulfatemonohydrate(manganesesulfate)

GB/T15901-1995Chemicalreagentcopperchloridedihydrate(copperchloride)

GB/T629-1997chemicalreagentsodiumhydroxide

GB/T1264-1997chemicalreagentsodiumfluoride

GB/T640-1997chemicalreagentsodiumbicarbonate

GB/T671-1998chemicalreagentmagnesiumsulfate

GB/T689-1998chemicalreagentpyridine

GB/T1401-1998chemicalreagentdisodiumedetate

GB/T1268-1998chemicalreagentsodiumthiocyanate

GB/T642-1999chemicalreagentpotassiumdichromate

GB/T649-1999chemicalreagentPotassiumbromide

GB/T684-1999chemicalreagenttoluene

GB/T1276-1999chemicalreagentammoniumfluoride

GB/T2305-2000Chemicalreagentphosphoruspentoxide

GB/T6684-2002chemicalreagent30%hydrogenperoxide

GB/T678-2002chemicalreagentethanol(absoluteethanol)

GB/T12591-2002chemicalreagentether

GB/T682-2002chemicalreagentchloroform

GB/T679-2002chemicalreagentethanol(95%)

PreparationofGB/T601-2002chemicalreagentstandardtitrationsolution

PreparationofpreparationsandproductsusedinGB/T603-2002chemicalreagenttestmethod

GB/T602-2002PreparationofStandardSolutionforImpurityDeterminationofChemicalReagents

GB/T652-2003ChemicalReagentBariumChloride

GB/T1265-2003chemicalreagentsodiumbromide

GB/T606-2003chemicalreagentwaterdeterminationgeneralmethodKarlFischermethod

GB/T674-2003chemicalreagentPowderedcopperoxide

GB/T656-2003chemicalreagentammoniumdichromate

GB/T16493-1996chemicalreagenttrisodiumcitratedihydrate(trisodiumcitrate)

GB/T16494-1996chemicalreagentxylene

GB/T16496-1996chemicalreagentpotassiumsulfate

GB/T16983-1997chemicalreagenttwoMethylchloride

GB/T17521-1998ChemicalreagentN,N-dimethylformamide

GB/T615-2006Generalmethodforthedeterminationofboilingrangeofchemicalreagent

GB/T9721-2006GeneralRulesofChemicalReagentMolecularAbsorptionSpectrophotometry(UVandVisibleLightPart)

GB/T1263-2006ChemicalReagentDisodiumHydrogenPhosphateDodecahydrate(DisodiumHydrogenPhosphate))

GB/T1266-2006chemicalreagentsodiumchloride

GB/T617-2006generalmethodforthedeterminationofmeltingpointrangeofchemicalreagent

GB/T9722-2006GeneralPrinciplesofGasChromatographyforChemicalReagents

GB/T605-2006GeneralMethodforChromaticityDeterminationofChemicalReagents

GB/T614-2006GeneralMethodforDeterminationofRefractiveIndexofChemicalReagents

GB/T622-2006ChemicalReagentHydrochloricAcid

GB/T626-2006ChemicalReagentNitricAcid

GB/T616-2006GeneralMethodforBoilingPointDeterminationofChemicalReagents

GB/T9739-2006Chemicalreagentirondeterminationgeneralmethod

GB/T683-2006Chemicalreagentmethanol

GB/T611-2006ChemicalreagentdensityGeneralmethodofdetermination

GB/T618-2006Generalmethodfordeterminationofcrystallizationpointofchemicalreagents

GB/T673-2006Chemicalreagentofarsenictrioxide

GB/T609-2006Generalmethodfordeterminationoftotalnitrogeninchemicalreagents

GB/T637-2006Chemicalreagentsodiumthiosulfatepentahydrate(sodiumthiosulfate)

GB/T672-2006Chemicalreagentmagnesiumchloridehexahydrate(magnesiumchloride)

GB/T658-2006Chemicalreagentammoniumchloride

GB/T621-1993ChemicalReagentHydrobromicAcid

GB/T9725-2007GeneralRulesforPotentiometricTitrationofChemicalReagents

GB/T9726-2007GeneralRulesforDeterminationofPotassiumPermanganateSubstancesReducedbyChemicalReagents

GB/T9732-2007Generalmethodforthedeterminationofammoniumwithchemicalreagents

GB/T9730-2007Generalmethodforthedeterminationofoxalatewithchemicalreagents

GB/T9724-2007GeneralrulesforthedeterminationofpHvalueofchemicalreagents

GB/T9729-2007Generalmethodforthedeterminationofchlorideinchemicalreagents

GB/T631-2007Ammoniawaterforchemicalreagents

GB/T613-2007Generalmethodfordeterminationofspecificopticalpower(specificopticalrotation)ofchemicalreagents

GB/T638-2007Chemicalreagentstannouschloridedihydrate(Ⅱ)(stannouschloride)

GB/T6685-2007chemicalreagenthydroxylaminechloride(hydroxylaminehydrochloride)

GB/T625-2007chemicalreagentsulfuricacid

GB/T676-2007ChemicalReagentAceticAcid(GlacialAceticAcid)

GB/T9731-2007ChemicalReagentGeneralMethodforDeterminationofSulfurCompounds

GB/T1272-2007ChemicalReagentPotassiumIodide

GB/T9727-2007Generalmethodforthedeterminationofphosphateinchemicalreagents

GB/T10726-2007Generalmethodforthedeterminationofmetalimpuritiesbychemicalreagentsolventextraction-atomicabsorptionspectrometry

GB/T9723-2007GeneralRulesofFlameAtomicAbsorptionSpectrometryforChemicalReagents

GB/T670-2007ChemicalReagentSilverNitrate

GB/T12589-2007ChemicalReagentEthylAcetate

GB/T665-2007ChemicalReagentAnhydrousCopperSulfate(Ⅱ)(CopperSulfate)

GB/T9728-2007GeneralMethodforDeterminationofSulfateinChemicalReagents

GB/T633-1994chemicalreagentsodiumnitrite

GB/T650-1993chemicalreagentpotassiumbromate

GB/T1279-2008chemicalreagentironsulfatedodecahydrate(Ⅲ)Ammonium

GB/T2304-2008chemicalreagentarsenic-freezincparticles

GB/T9734-2008chemicalreagentaluminumdeterminationgeneralmethod

GB/T9855-2008chemicalreagentcitricacidmonohydrate(citricacid)

GB/T696-2008chemicalreagenturea(urea)

GB/T660-1992chemicalreagentammoniumthiocyanate

GB/T1291-2008chemicalreagentpotassiumhydrogenphthalate

GB/T10705-2008Chemicalreagent5-sulfosalicylicaciddihydrate(5-sulfosalicylicacid)

GB/T9854-2008Chemicalreagentoxalicaciddihydrate(oxalicacid)

GB/T610-2008chemicalreagentgeneralmethodfordeterminationofarsenic

GB/T1273-2008chemicalreagentpotassiumhexacyanoferrate(Ⅱ)trihydrate(potassiumferrocyanide)

GB/T9742-2008Generalmethodfordeterminationofsilicateinchemicalreagents

GB/T9741-2008Generalmethodfordeterminationofignitionresiduesinchemicalreagents

GB/T9737-2008GeneralRulesfortheDeterminationofEasilyCarbonizedSubstancesinChemicalReagents

GB/T9740-2008GeneralMethodforDeterminationofEvaporationResiduesinChemicalReagents

GB/T632-2008ChemicalReagentSodiumTetraborateDecahydrate(tetraborateSodium)

GB/T2306-2008chemicalreagentpotassiumhydroxide

GB/T639-2008chemicalreagentanhydroussodiumcarbonate

GB/T15894-2008Chemicalreagentpetroleumether

GB/T1292-2008Chemicalreagentammoniumacetate

GB/T686-2008Chemicalreagentacetone

GB/T690-2008chemicalreagentbenzene

GB/T1294-2008chemicalreagentL(+)-tartaricacid

GB/T9733-2008chemicalreagentcarbonylcompounddeterminationgeneralmethod

GB/T9735-2008Generalmethodforthedeterminationofheavymetalsinchemicalreagents

GB/T9736-2008Generalmethodforthedeterminationofacidityandalkalinityofchemicalreagents

GB/T9738-2008Generalmethodfordeterminationofwater-insolublematterinchemicalreagents

GB/T15355-2008Chemicalreagentnickelchloridehexahydrate(nickelchloride)

GB/T643-2008ChemicalreagenthighmanganesePotassiumacid

GB/T3914-2008Chemicalreagentanodicstrippingvoltammetrygeneralrules

GB/T12590-2008Chemicalreagentn-butanol

GB/T9853-2008Chemicalreagentanhydroussodiumsulfate

GB/T667-1995Chemicalreagentzincnitratehexahydrate(zincnitrate)

GB/T669-1994ChemistryReagentstrontiumnitrate

GB/T685-1993chemicalreagentformaldehydesolution

GB/T691-1994chemicalreagentaniline

GB/T693-1996chemistryReagentsodiumacetatetrihydrate(sodiumacetate)

GB/T694-1995chemicalreagentanhydroussodiumacetate

GB/T11547-2008plasticliquidchemicalreagentresistancedetermination

GB/T23942-2009ChemicalReagentGeneralPrinciplesofInductivelyCoupledPlasmaAtomicEmissionSpectrometry

GB/T657-2011ChemicalReagentAmmoniumMolybdateTetrahydrate(AmmoniumMolybdate)

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GB/T659-2011chemicalreagentammoniumnitrate

GB/T1281-2011chemicalreagentbromine

GB/T623-2011chemicalreagentperchloricacid

GB/T644-2011chemicalreagentpotassiumhexacyanoferrate(Ⅲ)potassiumferricyanide(potassiumferricyanide)

GB/T661-2011chemicalreagentironsulfatehexahydrate(Ⅱ)Ammonium(ammoniumferroussulfate)

GB/T646-2011chemicalreagentpotassiumchloride

GB/T664-2011chemicalreagentferroussulfateheptahydrate(ferroussulfate)

GB/T620-2011chemicalreagenthydrofluoricacid

GB/T688-2011chemicalreagentcarbontetrachloride

GB/T647-2011Chemicalreagentpotassiumnitrate

GB/T636-2011Chemicalreagentsodiumnitrate

GB/T677-2011Chemicalreagentaceticanhydride

GB/T666-2011Chemicalreagentzincsulfateheptahydrate(zincsulfate)

GB/T1271-2011Chemicalreagentpotassiumfluoridedihydrate(potassiumfluoride)

GB/T641-2011Chemicalreagentpotassiumperoxodisulfate(potassiumpersulfate)

GB/T655-2011chemicalreagentammoniumpersulfate

GB/T15354-2011chemicalreagenttributylphosphate

GB/T645-2011chemicalreagentpotassiumchlorate

GB/T653-2011chemicalreagentbariumnitrate

GB/T628-2011chemicalreagentboricacid

GB/T687-2011chemicalreagentglycerol

GB/T675-2011chemicalreagentiodine

GB/T651-2011chemicalreagentpotassiumiodate

GB/T1274-2011Chemicalreagentpotassiumdihydrogenphosphate

GB/T648-2011Chemicalreagentpotassiumthiocyanate

GB/T1288-2011Chemicalreagentpotassiumsodiumtartratetetrahydrate(potassiumsodiumtartrate)

GB/T1267-2011chemicalreagentsodiumdihydrogenphosphatedihydrate(sodiumdihydrogenphosphate)

GB/T654-2011chemicalreagentbariumcarbonate

GB/T1270-1996chemicalreagentcobaltchloridehexahydrate(cobaltchloride)

GB/T1278-1994chemicalreagentammoniumbifluoride

GB/T1282-1996Chemicalreagentphosphoricacid

GB/T1285-1994Chemicalreagentcadmiumchloride

GB/T1289-1994Chemicalreagentsodiumoxalate

GB/T1396-1993chemicalreagentammoniumsulfate

GB/T1397-1995chemicalreagentpotassiumcarbonate

GB/T1400-1993chemicalreagenthexamethylenetetramine

GB/T13353-1992Determinationoftheresistanceofadhesivestochemicalreagents.MetalsandmetalsTitle:

Content-basedtitle

Standardsubstance,standardsolution,standardimpuritysolution,standardreferencesubstance,standardsample,linestandardreagent,indicatorreagent,referencesubstance,benchmarkReagents,chemicalstandards,chemicalstandards,instrumentstandards,analyticalreagents,first-classreagents,second-classreagents,ultra-purereagents,high-purityreagents,equivalentreagents,pharmaceuticalstandards,pesticidestandards,spectralpurity,chromatographicpurity,electronicpurity,steelstandardsSample,pigironstandardsample,coalstandardsample,orestandardsample,etc...

Appellationbasedonusage

Chemicalreagents,generalreagents,analyticalreagents,diagnosticreagents,teachingreagents,Experimentalreagents,separationtools,buffersolutions,indicatorreagents,biologicalstains,photosensitivematerials,syntheticreagents,intermediates,chemicalrawmaterials,waterqualityanalysis,residualpesticidetesting,molecularbiologyreagents...

Source-basedtitles

Importedreagents,naturalextracts,extracts,drypowders,extracts...

Custom-basedtitles

Chemicals,Finechemicals,pharmaceuticals,coldpartialreagents,specialreagents,first-classreagents,second-classreagents,third-classreagents,smallvarietyreagents...

Appellationsbasedonproperties

Inorganicreagents,organicreagents,isotopesandlabeledcompounds,biochemicalreagents,aminoacidsandtheirderivatives,proteinsandpeptides,nucleotidesandtheirderivatives,monosaccharidesandpolysaccharides,enzymesandcoenzymes,antibiotics,vitamins,dyesandpigments,TrainingNutrients,chromatographicmedia,electrophoresismedia,biologicalbuffers...

Classificationbasis

Thecategoriesofchemicalreagentsarebasicallyclassifiedaccordingtotheirpurposeorsubjectmatter.Manynewcategorieshavebeenadded.Germany'sE.Merckcompanyisdividedinto20categoriesand88sub-categories.AmericanBaker(J.T.Baker)companyhas75majorcategoriesand124sub-categories.Withthedevelopmentofscienceandtechnology,thevarietyofchemicalreagentsisbecomingmoreandmorediverse,andthetrendofcategorydivisionisgettingmoreandmoredetailed,andithasreachedtheserializationandmatchingofvarieties.

QualityIndex

Thequalitylevelsofchemicalreagentsarecomplexandtherearemanyvarieties,whichareparticularlyconfusing.Thegeneralconventionalvarieties(class1reagents)areessentialvarieties,andthereare225species,whicharebasicallycomplementaryproducedinmycountry'schemicalreagentbasesinBeijing,Tianjin,Shanghai,Xi'an,Chengdu,Guangzhou,andShenyang.TypeIIreagentsareusedinalmostallfields,andtheyarealsonecessaryvarietiesformanufacturers.Thereareabout1800-2000varieties.Suchreagentsareinlargedemandandwidelyused.Thereareabout3000-6000varietiesofthethreetypesofreagents,andmostoftheirapplicationfieldsarerelatedtothenationaleconomyandpeople'slivelihood,suchaschemical,metallurgy,electricpower,food,medicineandhealthandotherindustriesthatarespecificallyusedinindustryreagents.

Inmycountry,thereare225kindsofchemicalreagentsrepresentedbythreegrades:premiumgrade,analyticalgrade,andchemicalgrade,accordingtothenationalstandardsofthePeople’sRepublicofChinaandthestandardsissuedbytheformerMinistryofChemicalIndustry.These225kindsofchemicalreagents,intheformofstandards,stipulatethebasisofthecontentofchemicalreagentsinourcountry.Thecontentdeterminationofotherchemicalsisbasedonthis,andthecontentisdeterminedbymeasurement.Therefore,thequalityofthesechemicalreagentsisveryimportant.Atthesametime,these225chemicalreagentshavebecomebasicvarietiesduetotheirextremelywideuse.These225specieshavebeenmarkedinthecatalogofchemicalreagents.Inaddition,therearespecialreagents,theproductionvolumeisverysmall,almoston-demandproduction,thequantityisgenerallydesignatedbytheuser.

Commonqualitylevels

Excellentgradepure(GR,greenlabel):highcontentofmaincomponents,highpurity,suitableforpreciseanalysisandresearchwork,andsomecanbeusedasbenchmarkssubstance.

Analyticalpurity(AR,redlabel):highcontentofmaincomponents,highpurity,lowinterferenceimpurities,suitableforindustrialanalysisandchemicalexperiments.EquivalenttoforeignACSlevel(AmericanChemicalSocietystandard)

Chemicalpurity(CP,bluelabel):highcontentofmaincomponents,highpurity,presenceofinterferingimpurities,suitableforchemicalexperimentsandsyntheticpreparation.

Experimentalpure(LR,yellowlabel):highcontentofmaincomponents,poorpurity,nochoiceofimpuritycontent,onlysuitableforgeneralchemicalexperimentsandsyntheticpreparation.

Indicatorsandstains(IDorSR,purplelabel):requiresuniquesensitivity.

Designatedlevel(ZD):Chemicalreagentscustomizedforspecificusersinaccordancewiththequalitycontrolindicatorsrequiredbyusers.

Electronicpure(MOS):suitablefortheproductionofelectronicproducts,withextremelylowelectricalimpuritycontent.

Equivalentreagents(3N,4N,5N):themaincomponentcontentisrespectively99.9%,99.99%,99.999%ormore.

Spectralpurity:thepurityofthemaincomponentsis99.99%

Leveldescription:

Superiorgradepure—GR

MicroorganismUse—FMB

AnalysisPure-AR

Industrial-TECH

ChemicalPure—CP

Internship—PRACT

Experimentallevel—LR

Forsynthesis—FS

Biochemicalgrade—BC

Indicator—IND

HighperformanceLiquidchromatography—HPLC

Gaschromatography—GC

Biologicalstaining—BS

Liquidchromatography—LC

Baselinelevel—PT

ChromatographyUse—FCP

AtomicAbsorption—AAS

Thinlayerchromatography—TLC

Infraredabsorption—IR

SpectrumPure—SP

NuclearMagneticResonance—NMR

SpectroscopyPure—UV

Fluorescenceanalysis—FIA

Synthesis—SYN

Inorganicanalyticalreagentsarecommonlyusedinorganicchemicalsforchemicalanalysis.Itspurityishigherthanthatofindustrialproducts,withlessimpurities.

Organicreagentsforinorganicanalysisarespecialorganiccompoundssuchasprecipitationagents,extractants,chelatingagentsandindicatorsforthedetermination,separationandenrichmentofelementsintheanalysisofinorganicsubstances,Ratherthangeneralsolvents,organicacidsandorganicbases.Theseorganicreagentsmusthavegoodsensitivityandselectivity.Withthedevelopmentofanalyticalchemistryandchemicalindustry,suchreagentswithbettersensitivityandselectivitywillbedeveloped,suchasthosethathavecomplexingabilityforsomemetals(suchasalkalimetals,alkalineearthmetals)andammoniumionssince1967.ThisisthecasewithCrownethercompounds.

Primarystandardsarecompoundswithhighpurity,lessimpurities,goodstabilityandconstantchemicalcomposition.Inthereferencereagents,thereareclassificationssuchasvolumetricanalysis,pHmeasurement,andcalorificvaluemeasurement.Eachcategoryisdividedintothefirstbenchmarkandtheworkingbenchmark.AllthefirstbenchmarksmustbeverifiedbytheNationalAcademyofMetrology,andtheproductionunitusesthefirstbenchmarkasthemeasurementstandardforworkbenchmarkproducts.Thebenchmarkreagentsforcommercialoperationsmainlyrefertothevolumetricanalysisworkbenchmarksinthevolumetricanalysiscategory[contentrangeis99.95%to100.05%(weighttitration)].Generallyusedtocalibratethetitrant.

Standardsubstanceisachemicalsubstanceusedforcomparisoninchemicalanalysisandinstrumentanalysis,orachemicalusedtocalibrateaninstrument.Itschemicalcomposition,content,physicalandchemicalpropertiesandimpuritiesmustbeknown,andmeettheregulationsorberecognized.

ReagentMicro-analyticalreagent(Micro-analyticalreagent)issuitableforthedeterminationofthesubstance,theallowableamountisonlyaconstantonepercent(weightisabout1~15mg,volumeisabout0.01~2ml)Reagentsformicroanalysis.

Organicanalyticalstandardsarechemicalreagentsusedforcomparisonwhendeterminingthecompositionandstructureoforganiccompounds.Itscompositionmustbeaccuratelyknown.Itcanalsobeusedformicroanalysis.

Pesticideanalyticalstandards(Pesticideanalyticalstandards)aresuitableforuseingaschromatographytoanalyzepesticidesordeterminepesticideresiduesascomparisonitems.Itscontentisrequiredtobeprecise.Therearesolutionspreparedfromatraceamountofasinglepesticide,andtherearealsomixedsolutionspreparedfrommultiplepesticides.

Refractiveindexliquid(Refractiveindexliquid)isahigh-puritystableliquidwithaknownrefractiveindex,usedtodeterminetherefractiveindexofcrystallinesubstancesandminerals.Therefractiveindexismarkedontheoutsideofeachpackage.

Normalsolutionisanaqueoussolutioncontainingonegramequivalentofsoluteinoneliterofsolution,thatis,asolutionwithaconcentrationof1N.IndicatorIndicator(Indicator)isasubstancethatcanchangeitscolorundertheinfluenceofthepresenceofcertainsubstances.Itismainlyusedtoindicatetheendpointoftitrationinvolumetricanalysis.Generallycanbedividedintoacid-baseindicator,redoxindicator,adsorptionindicatorandsoon.Inadditiontoanalysis,theindicatorcanalsobeusedtotestthepresenceofcertainharmfulandtoxicsubstancesingasesorsolutions.

Testpaperisasmalldrypieceofpapersoakedinanindicatororreagentsolution.Itisusedtotestthepresenceofacertaincompound,elementorioninthesolution.Itisalsousedformedicaldiagnosis.Instrumentalanalyticalreagents

Instrumentalanalyticalreagentsarereagentsusedintheprocessofsampleanalysisusingspecialinstrumentsdesignedaccordingtotheprinciplesofphysics,chemistryorphysicalchemistry.Atomicabsorptionspectroscopystandards

Atomicabsorptionspectroscopystandardsareusedasstandardreagentswhenanalyzingsamplesbyatomicabsorptionspectroscopy.

Forchromatographyreagentsforchromatographyrefertoreagentsandmaterialsusedingaschromatography,liquidchromatography,gas-liquidchromatography,thin-layerchromatography,columnchromatographyandotheranalyticalmethods.Therearestationaryliquids,Supports,solvents,etc.

Forelectronmicroscopy(Forelectronmicroscopy)reagentsarefixatives,embeddingagents,stainsandotherreagentsusedinthefieldsofbiology,medicine,etc.,whenelectronmicroscopesareusedforresearchwork.

SolventforNMRspectroscopy(SolventforNMRspectroscopy)ismainlyadeuteratedsolvent(alsocalledheavyhydrogenreagentordeuteratedreagent),whichisthehydrogenintheorganicsolventstructureisdeuterated(heavyHydrogen)replacedbythesolvent.Innuclearmagneticresonanceanalysis,thedeuteratedsolventmaynotshowpeaks,anditwillnotinterferewiththehydrogenspectrumanalysisofthesample.

Forpolarography(Forpolarography)reagentsrefertothereagentsneededforquantitativeandqualitativeanalysisbypolarography.

SpectralpuritySpectrographyreagentsusuallyrefertoreagentswithhigherpuritythathavebeenanalyzedbyemissionspectroscopy.

Spectrophotometricpurereagentreferstothesolutionusedwhenspectrophotometricanalysisisused.Ithasacertainwavelengthtransmittanceandisusedforqualitativeandquantitativeanalysis.

BiochemicalreagentsBiochemicalreagentsrefertobiologicalmaterialsororganiccompoundsrelatedtolifescienceresearch,aswellasreagentsforclinicaldiagnosisandmedicalresearch.Duetothewiderangeandrapiddevelopmentoflifesciences,thiskindofreagentshasawidevarietyandcomplexproperties.

Otherlevels

Inaddition,itisstilldividedintothefollowingmorethan20levels.

AASatomicabsorptionspectroscopy,BCbiochemicalreagents,BPBritishPharmacopoeia,BRbiologicalreagents,BSbiologicalstains,CRchemicalreagents,EPultra-pure,FCPchromatography,FMPmicroscopy,FSsynthesis,GCgaschromatography,GRsuperiorgradepurereagent,HPLChighpressureliquidchromatography,IDindicator,IRinfraredabsorptionspectrum,MARtraceanalysisreagent,NMRnuclearmagneticresonancespectroscopy,OASorganicanalysisstandard,PAanalysis,Practpractice,PTstandardReagents,Purissspecialpure,Purumpure,SPspectralpure,Techindustrialuse,TLCthinlayerchromatography,UPultra-pure,USPUnitedStatesPharmacopoeia,UVultravioletspectrophotometrypure,JXteachingreagent...MIpharmaceuticalgrade,Iindustrialgrade,FFoodgrade,Mcosmeticgrade,Ssolid,Lliquid,Efineproduct,Ccrudeproduct...

Obviously,thegeneralqualitystandardsofthesechemicalreagentsaredividedintotheabove-mentionedqualitylevels,whichisfarfrombeingsatisfied.Researchandproductionneeds.

Validityperiodofchemicalreagents

Chemicalreagentsareaffectedbyexternalfactorssuchastemperature,lightirradiation,airandwaterduringstorage,transportationandsales,andarepronetodeliquescent,Physicalandchemicalchangessuchasmycin,discoloration,polymerization,oxidation,volatilization,sublimationanddecompositionmakeitinvalidandunusable.Therefore,itisnecessarytoadoptreasonablepackaging,appropriatestorageconditionsandtransportationmethodstoensurethatthechemicalreagentsdonotdeteriorateduringstorage,transportationandsales.Somespecialrequirementsforstorageandtransportationshouldbehandledinaccordancewithspecialrequirements.Somechemicalreagentshaveacertainshelflife,sobecarefulwhenusingthem.

Thevalidityperiodofchemicalreagentsvariesgreatlywiththechemicalpropertiesofchemicals.Undernormalcircumstances,chemicallystablesubstanceshavealongershelflifeandsimplerstorageconditions.

StabilityJudgmentPrinciples

Forpreliminaryjudgmentofthestabilityofasubstance,thefollowingprinciplescanbefollowed:

Inorganiccompounds,aslongastheyareproperlystored,thepackagingisintact,Canbeusedforalongtime.However,thosesubstancesthatareeasilyoxidizedanddeliquescentcanonlybestoredforashortperiodoftime(1to5years)underdark,cool,anddryconditions,dependingonwhetherthepackagingandstorageconditionscomplywiththeregulations.

Organiclow-molecular-weightcompoundsaregenerallymorevolatile,andthepackaginghasbetterairtightnessandcanbestoredforalongtime.Butitiseasytobeoxidized,decomposedbyheat,easytopolymerize,photosensitivesubstances,etc.

Organicpolymers,especiallylifematerialssuchasoils,polysaccharides,proteins,enzymes,peptides,etc.,areextremelysusceptibletotheeffectsofmicroorganisms,temperature,andlight,andlosetheiractivityordeteriorate.Therefore,theymustberefrigerated(Frozen)preserved,andthetimeisshorter.

Inprinciple,referencematerials,referencematerialsandhigh-puritymaterialsshouldbestoredinstrictaccordancewiththepreservationregulationstoensurethatthepackagingisintact,avoidbeingaffectedbythechemicalenvironment,andthestoragetimeshouldnotbetoolong.Ingeneral,thereferencesubstancemustbeusedwithinthevalidityperiod.

Thestabilityofmostchemicalsisstillrelativelygood,andthespecificconditionsshouldbedeterminedbyactualuserequirements.Iftheanalysisdataisgenerallyunderstood,ortheanalysisresultsdonothavespecificandaccuraterequirements,suchasgeneralteachingexperiments,generalrequirementscanbemadeforthequalitylevelofchemicalreagents.However,thefactorytestdataisusedtoguideproduction,andthequalityindicatorsofchemicalreagentsmustnotbeambiguous.Asforthechemicalreagentsusedingeneralsyntheticpreparation,inmostcases,theuseofindustrial-gradechemicalreagentsissufficient.However,thesyntheticpreparationofresearch-typeandcertainspecialchemicals,insomecases,hasverystrictrequirementsonthequalityofrawmaterialsandrequiresstrictcontrol.

Inactualuse,peoplearealwaysaccustomedtojudgingtheeffectivenessofchemicalreagentsbythedateofproduction.Infact,itisridiculous.Forexample,inaninstitutionofhigherlearning,wehaveseenwarehousemanagerscleanoutallchemicalreagentsthathavebeenoutofthefactoryformorethan2years,andpreparethemfordestruction.Thereasonisthattheyhaveexpired.Nottomentionthehugewasteoffunds,thedestructionplanofthevariouschemicalhazardousmaterialsaloneisenoughtobeprohibitive.What'smore,commercialcompaniesarenotallowedtobuy,topreventbusinessesfrom"deceivingpeople",thesituationislamentable,andthesituationissad!Later,itissaidthattheselargequantitiesofchemicalreagentswere"deeplydugandburied".

Inshort,theeffectivenessofchemicalreagentsmustfirstbejudgedbasedonthephysicalandchemicalpropertiesofthechemicalreagentsthemselves,andthenthestorageconditionsofthechemicalreagentsshouldbeobservedvisually,andthenwhethertheycanbeusedaccordingtospecificneedsTheconclusion.

Classificationofchemicalreagents

Currentsituationinmycountry

Thereasonableclassificationofchemicalreagentsisfarfrommeetingtheneedsofscientificresearchandproductionduetothedraftingofnationalstandards,anditisseriousIthinderstheproductionofchemicalreagentsinmycountry.Relyingontheexisting227nationalstandardsandindustrystandardsalone,itisdifficulttogivesuchalargenumberofchemicalreagentstoaqualitystandard;itisimpossibleforustogiveallchemicalsanationalqualitystandard,eventomentionWhenitcomestoreagents,thefirstthingpeoplethinkofiswhetheritisanalyticallypureorchemicallypure.Evenwhenpeoplebuy,nomatterwhatthepurposeis,theydon’tbuynon-analyticalreagents.Thisisalsothereasonwhymanyvarietiesthatdonothavenationalstandards,butinexplicablyandbaselesslyendowproductswitharedARlabel.Itisalsobecauseinactualuse,inmanycases,thetrue"analyticalpurity"isnotrequired,andillegalmanufacturersdeliberatelylabeltheindustrialproductswith"analyticalpurity"toconfusethepuritylevel.Althoughqualityaccidentswillnotoccurinmostcases,butHowever,itseriouslyinterfereswiththeproductionanduseofreal"standardmaterialsandanalyticalgrades".

Furthermore,sincethenumberofconventionalchemicalsishuge,butthereareonly225varietiesclassifiedassuperiorgrade,analyticalgradeorchemicalgrade,then,whatelseisnecessary!

Thedifferencebetweenmycountryandtheworld

Internationally,thereisanincreasingtrendtolabelthegradeandpurityofchemicalreagentsaccordingtothemaincontentandphysicalconstantsofchemicals.Itisgenerallybelievedthatwhenthemaincontent,boilingpoint,meltingpoint,density,refractiveindex,andevenultraviolet,infrared,andnuclearmagneticspectraareallknown,thepurityandscopeofapplicationofasubstancecanbecompletelydetermined.Thisisthemaindifferencebetweenthelabelcontentofchemicalreagentsinmycountryandthatofforeignchemicalreagentlabels.

Actually,theso-calledchemicalreagentsarethemedicamentsusedinchemicalexperiments;thatis,thechemicalmedicamentsneededinchemicalexperiments.Theclassificationofchemicalpurityandgradecanbedeterminedaccordingtothequalitystandardsandscopeofapplicationofchemicalagents.

Classification

Accordingtothis,thefirstlevelofchemicalreagentsisdividedintofourcategories:standardreagents,biochemicalreagents,electronicreagents,andexperimentalreagents.

Theclassificationprincipleoflevel1standardnotonlyclarifiesthequalitystandard,butalsotakesintoaccountthescopeofapplicationofthechemicalreagent.

Thelevel2standardisafurtherdivisionbasedonthelevel1classification.Itisafurtherclarificationandlimitationofthelevel1standard.

tothreecriteriaarecomparedwiththeoriginaloldstandard,ormoreaccuratedeterminationofthespecifiedpurposes.

intheLevel1or2isdetermined,aqualityindicatorofthechemicalagent,andthepurposeofthisapplicationthequalityindicatorscanbeappliedalsodetermined.

SoIproposewillbepublishedasananalyticalexaminationofthecriteriaandstandards"standardreagent"qualitystandardsgiveclearnationalstandards.Theremaining"biochemicalreagents,electronicreagents,laboratoryreagents"qualityindicatorscanfollowcorporatestandards,orupdatetheincreasinglytechnologicalrequirementsofdiscretionbythemarket,sothatwechemicalsindustrywillbeabletogetoutoftheoriginal"deadset"ofoldtraditions,developmentboomingup!

standardreagentsBZ:inaccordancewithinternationalnormsandtechnicalrequirementsinordertoidentifyasastandardsubstanceanalysisarbitration.

BiochemicalsSH:preparationbiochemistryandbiochemicalsynthesis.

electrophilesDZ:generallyreferstothechemicalsandmaterialsusedinelectronicinformationindustry,includingintegratedcircuitsanddiscretedeviceschemicals,theprintedcircuitboardsupportingchemicals,chemicalsandsurfacemountdisplaychemicalsandotherdevices.

ReagentsSY:accordingtothe"maincontent"determined"syntheticreagent."Reagentsusedinthesyntheticchemistrylaboratorypreparation,separationandpurification,tomeetthegeneralrequirementsofsynthesisreagents.

tagschemicals

QualityIndexchemicalsdeterminestheapplicablerangeofchemicalreagents,soIrecommend,shouldannouncetheapprovalofa"chemicalreagentlabel"nationalstandard,thestandardagivenchemicalreagentsandstandardizedqualityindicatorsdescribethesystemwillregulatetheproductionofchemicalreagents,rationaluseofgreatsignificance.

"Chemicalreagentstag"bearinginformation:

registeredtrademark:clearlylabeledregisteredtrademarksofthemanufacturers.

QualityStandard:QualityStandardsimultaneouslydisplaycolorandpinyincodesintwoways.Colordisplayareaasalowerlabelmanufacturerinformationregion;pinyincodes(suchasBZ,SH,DZ,SY)indicatedinaprominentposition.

Chinesenameandtype:ProductnameChineseChemicalSocietyin1982published"inorganicchemicalnomenclaturesystems,""organicchemicalsnomenclaturesystem"asthemainbasis,takingintoaccountthelong-termuseofthecommonname,Productname.Andcanbedescribedasaccuratelyaspossiblegivenpatternsordosageofthechemicalagent,forexample:anaqueousalcoholsolution,powder,blocks,sticks,paste,suchasa200meshsizeoreventhelike.

EnglishName:NametoIUPAC1982Nianpublished"inorganicchemicalnomenclaturesystems,""organicchemicalsnomenclaturesystem"asthemainbasis,takingintoaccountthecommonname,tradename,long-termuse.

CASAccessionNumber:consistsof9digitsinsquarebrackets,hyphendividedintothreeparts,e.g.,[58-08-2]CASRegistryNumberiscaffeine.

=molecularformula:MolecularSimplecorrectlywritten,i.e.,theamountofmolecularformulashown,inaccordancewiththe1968publicationoftheinternationalatomicaccuratelycalculatethemolecularweight.TheNaOH=40.10.

content:percentagecontentbymassofthechemicalagentinaccordancewiththemethodspecifiedmolecularnationalstandardsorcorporatestandard,determined.The99.9%.

Packingamount:theamountofsolidmatterofthepackageisgivenmassofchemicalagent,suchas1g,5g,10g,25g,100g,250g,500g,1000glike.Theliquidorgaseouschemicalsgivenamountofpackagingvolume,suchas1ml,5ml,10ml,25ml,100ml,250ml,500ml,1000mlandthelike.

Appearance:concise,accuratetermtodescribethephysicalstateofthecolorofthechemicalagent,odor,andotherphysicalstate.

physicalconstants:sequentiallyintheordergivenphysicalconstantsmeasuredvalue"meltingpoint,boilingpoint,density,viscosity,opticalrotation,refractioncoefficient,solubility"andthelike.

whereinSpectrum:anda"UV,IR,NMRspectroscopy"othercharacteristicabsorptionpeaks.

interferingimpurities:primarilygivenmasspercentageofimpurities,inparticularthemaininterferenceaccuratemeasuredvalueofthemasspercentageofimpurities.

DGRNo:hazardousgoodsmustbemarkedDGRnumber.Productionbatch:givenproductionlotinordertofacilitatetraceability.

whereinforeigndevelopmentofchemicalreagents

tocompletedevelopment,alternatedirectionsreagentandancillaryservices

ancillarybenefits,likeimproveduserservice.Onforeignmarkets,almostindustrial,routineexperimentationandtestingprojectsinagriculture,health,environmentalprotection,scientificresearch,teaching,therearesetsofteststrip,completesolution,pre-filledcolumn,paintedsheets,variousreferencestandardandspecialeasytousetoolsandsmallequipment.Chemicalcompositionforeignmarketshasspecificreagents,suchasbasicmodulepeptide:p-aminoacids,FMOs(fluorenylmethoxycarbonylgroupZhuoyl)-aminoacidsandotheraminoacidsreagents;OrganicSynthesisbasicmodules:chloride,alcohol,phenols,aldehydes,amines,carboxylicacids,ketones,andthelike;andreagentscustomizedaccordingtouserrequirements.MostReagentCompany,fortheconvenienceofusers,butalsosupportingsalesoflaboratoryinstrumentsoftenusedinsmall-scale,securesupplies,variousmapsdata(chemicalstructure,infrared,ultraviolet,emissionspectroscopy,chromatography,etc.),compoundsafetydata,variousdataanalysisandothertestingmethods,ofwhichaconsiderableportionispublishedonCD-Rom.

Manyagentsnotonlyselltangibleproducts,butalsotechnicalconsultingbusiness,providingawiderangeoftechnicalservices,suchas:analysisandtesting,intermediatescale-up,processdesignproducts,developenvironmentalprotectionprograms.

attachedgreatimportancetoscientificresearchanddevelopment

Thereagentscompanyhasitsownresearchanddevelopmentdepartment,mostcompaniesalsodevelopwithuniversities,researchinstitutes,individualscientistsorotherwell-knowncompanies,andevenmergersthecompanyhassometechnicalexpertise,inordertoenhancethecompany'sdevelopmentandcompetitiveness.Theyhesitatetoinvestheavilyinresearchanddevelopment,scienceandtechnologyinordertosuddenlyflyfierce,intothefiercecompetitioninthemarketdominantposition.ToMerckKGaA,forexample,their1994-Foreachyearbetween1998andfundsscientificresearchanddevelopmentinvestmentaccountedfortheproportionofsaleswere9.56%,9.O%,8.18%,9.76%and10.05%,overthesameperiod,Merck(Darm.)asfollows:43.52%,43.94%,45.29%,47.0%and46.95%.

production,managementandtechnologyadvances

Mostofthecompany'sfactory,haveachievedISO9001,ISO9002,GMPorFDAqualitymanagementcertification.On-siteproductionprocess,industrialhygieneandenvironmentalprotectionwidespreadattention.Inrecentyears,withthecategoryofvarietiessupplymarketcontinuestoexpand,manyofthemorecomplextechnologyhasbeenwidelyadopted.Applicationofcomputer-aidedproduction,technology,businessmanagement,hasbeenverycommon.MostReagentCompany,arebuiltonitsownInternetsite,inadditiontoreportedcompanyhistory,institutionalstructure,businessscope,catalogandothervarieties,mainlyonlineshopping,andconstantly(aboutaweek)postedoperatingstatusofthecompany,technicalachievements,internationalcooperation,planningguidelinesandotherinformation.TheirannualfixedassetinvestmentinhugenumbertoMerckKGaA,forexample,from1994-1998theproportionofinvestmentinfixedassetssalesaccountedfor7.2%,8.4%,7.4%,6.7%,7.7%(eg:1998to624millionmarks,equivalenttoRMB2.8billionyuan).

alliancecooperation,jointoperationisatrend

varietycategoriesofchemicalagentsisextremelycomplicated,extensiveserviceside,involvingalmostalltheeconomicandtechnologicalfields,anycompany,wantstosweepreagentsallbusinessisimpossible,andreagentsalesischaracterizedbybiggerandmoreandmorevarietiesofbusiness,increasesalesopportunities,thegreaterthelikelihoodofthatisprofit.So,20yearsago,thereisatrendofsmallcompaniesmoveclosertolargecompanies,smallcompaniesorlargecorporatemergersofmutualco-operation.Headabletosupplytheworld'slargestspeciesistheSigma-A1drichcompany,theyadvantageinthevarietyisalmostirreplaceable,thisisindeedtheresultofajointoperation.

Thenewtrendinthecountrythroughtheestablishmentofe-commerceplatformtoachieveintegration,alliances,jointventureseffects,likeAvatar,chemistry,Chineseagentsspecializeine-commercetradingplatformsuchreagentshasoccurred,thiswouldbeagoodintegrationofthedomesticagentresources.Becauseitconformstothedevelopmentofonlinesalesmodel,webelievethiswillbeamajortrendinthefuturereagentsbusiness.

safeuseofchemicalreagents

1.Chemicalsflammable

GeneralChemicalsflashpointbelow25℃flammablechemicalagentsincluded,theyaremostlyhighlyvolatileliquids,incaseoffiretoburn.Thelowertheflashpoint,themoreflammable.Commonflashpointpetroleumopened,ethylcondensateethane,diethylether,gasoline,twocarbonizedcarbon,withalkylenepropionate,benzene,ethylacetate,methylacetateinthefollowingyeast-4℃.

mustnotbeusedeasilywhenusingbrightfirealkenylChemicals.Heatcannotbedirectlyheatedbyaheater,generallydonothavewaterbath,suchchemicalagentsshouldbestoredinthecoolair,intherefrigerator,therefrigeratormustbeexplosionproof,therehadbeenstoredinaconventionalrefrigeratoretherandfire,accidentburnedtheentirelaboratory,wheretheuseofsuchalargenumberofchemicalreagents,looktomaintaingoodventilation,theuseofelectricalappliancesmustbeexplosion-proofelectricalequipment,thesitemustnothaveopenflames.

highlyflammablereagentsduringcombustioncanleadtoanexplosion,chemicalreagents,suchassomesolid:nitrocellulose,picricacid,trinitrotoluene,trinitrobenzene,oroverlappingazidecompound,saltHuoandsoon,frieditselfisburning,whenexposedtoheatorflame,whichburnseasilyordecomposition,explosion,itmustnotbeheateddirectlyintheuseofthesechemicals,shouldalsopayattentionsurroundingtheuseofthesechemicalsdonothaveanopenflame.

Anothertypeofsolidchemicalreagents,waterviolentreactioncanoccur,andemitalotofheat,cancauseanexplosion.Suchchemicalagentsaremetalpotassium,sodium,lithium,calcium,aluminumhydride,calciumcarbideandthelike,intheuseofthesechemicalagentsmustavoidtheirdirectcontactwithwater.

andsomesolidoncontactwithachemicalagentastrongoxidationcanoccur.Thephosphorus;somecontactwithanoxidizingagentorheatintheair,bytheimpactorfrictioncancauseabruptcombustionorexplosion.Thephosphorussulfide,redphosphorusmagnesium,zinc,aluminum,Rong,brainandthelikefall,whenusingthesechemicalagents,wemustpayattentionnottoohighambienttemperature(typicallynotmorethan30℃,preferably20℃orless)Avoidcontactwithstrongoxidizingagents.

Inthelaboratorypersonnelusingflammablechemicals,oughttowearthenecessaryprotectiveequipment,itisbesttowearprotectiveglasses.

2.ToxicChemicals

Generalchemicalsaretoxictohumans,mustbeavoidedwhenusingthelargenumberofinhalation,theagentperformancesAfteruse,towashtheirhands,wash,bath,replacingclothesforinhalationoringestionofsomesmallamountofdeaththatcanpoisonthechemicalagent,theamountofbiologicaltestdeath(LD50)isreferredtoastoxicchemicalagentsat50mg/kgorless,suchas:potassiumcyanide,sodiumcyanideandothercyanide,arsenictrioxideandcertainarsenide,mercurydichloride,mercuryandcertainsalts,sulfate,dimethylandthelike.Whenusingclearperformancechemicals,wemustunderstanditsLD50.Firstaidtreatmentatsomeofthecommonlyusedtoxicchemicalsmustunderstandthesetoxicchemicals,toxicchemicalsmusthaveaspecialpersontokeepstrictcontrolusage.

3.Corrosivechemicalagents

anychemicalagentacrosstheskin,mucousmembranes,eyes,respiratoryorgansmustbecleaned,inparticular,haveastrongcorrosivetotheskin,mucousmembranes,eyes,respiratorychemicalagents(whetherliquidorsolid),suchas:avarietyofacidsandbases,phosphorustrichloride,phosphorusoxychloride,bromine,phenol,Tianshuihydrazineandthelike.Butalsotoavoidhittingtheskin,mucousmembranes,eyes,respiratory,usebeforeusemustunderstandaidaccesstothesetreatmentmethodscorrosivechemicalagents.Usedilutealkalisuchasacidwashing,etc.spilledontheskin.

4.StrongoxidizingChemicals

strongoxidizingchemicalagentsareperoxidecontainingoxyacidorstrongoxidizingpoweranditssalts.Suchas:acidperoxide,Annnitrate,potassiumnitrate,perchloricacidandsaltsthereof,acidandsaltsthereofcomplexweight,permanganicacidanditssalts,peroxyacid,peraceticacid,sweetwine,phosphoruspentoxideandthelike.Strongoxidizingchemicalagentsunderappropriateconditionscanemitoxygenexplosion,andformexplosivemixtureswithorganicmagnesium,aluminum,zinc,sulfurandothercombustibles,somewatermayexplode,theuseofsuchastrongoxidizingchemicalinreagent,ambienttemperatureisnothigherthan30℃,goodventilationshouldnotbeorganicorreducingsubstanceswiththeuseofcommon(heating).

5.WhenRadiochemical

Theuseofsuchchemicalagents,theuseofradioactivematerialsaccordingtoacertainmethod,totakeprotectivemeasures.

distillationandrectificationchemicals

inthechemicalanalysis,instrumentalanalysis,thepreparationofinorganic,organicsynthesisandotherscientificexperimentareoftenencounteredwithinsufficientpuritychemicalsorbuytherequiredpuritychemicals,whichrequirespurificationofourownexistingchemicalsinthelaboratoryinordertoobtaintherequiredpuritychemicals.Apolloagentwillbesmallseriesfollowingbriefdistillationandrectificationmethods.

distillationandrectification

distillationandrectificationisawidelyusedmethodofpurification,mixingthecomponentsinaccordancewiththeliquidmixturebetweenliquidandvaportheinequalityofpurified,purificationisthefirstchoiceofvolatileandsemi-volatilechemicals.

adistillationprinciple

isseparatedbydistillationfromtheimpuritiescontainedinthechemicalagentvolatileandsemi-volatileimpuritiesandvolatileorsemi-volatileevaporatingbodyTheywillnotbevolatileandlessvolatileimpuritiesleftbehind.Changethesaturationvaporpressureofasubstanceatdifferenttemperaturesisthebasisoftheseparationbydistillation.Generallyspeaking,ifthevaporpressureoftheliquidmixtureoftwocomponentshavingalargedifferenceinthevaporphasecanbemorevolatileandsemi-volatilecomponentsenrichment.Twophases-liquidandvaporphases-canberecoveredseparately,volatileandsemi-volatilecomponentsintheenrichedvaporwithoutvolatilecomponentsareenrichedintheliquidphase.

Inadditiontothehydrocarbonmixtureandafewotherexamples,Raoult'slawandDalton'slawcanbeusedinsystemsoverthemixture,andthemixturesolutionisoftennotdesirabletofollowthevaporphase-phasebehavior.Applicationofthesetwolawscanbeavolatilethanthetwocomponentsofthebinarysystem(aAB):aAB=(YA/YB)/(XA/XB)=P0A/P0Bwherein,YAandYBaretheequilibriumcomponentsaandBinthegasphasemolefraction,XAandXBarethecomponentsaandBintheliquidphaseatequilibriummolefraction,andP0BareP0AvaporpressureofcomponentsaandBatequilibrium,obeysthelawsofRaouilt.WiththeincreaseaAB,alsoincreasesthedegreeofenrichment.

Second,asimpledistillation

simpledistillationapparatus,showninFigure-1.Whenaliquidsampleisheatedandconvertedintosteam,whichiscondensedpartbacktotheoriginaldistillationflask,whiletherestiscondensedandtransferredtoacollectionvessel,theformeriscalledrefluxliquid,whichiscalledeffluent.Sincethedistillationiscarriedoutcontinuously,escapeandstoredintheliquidcompositionisgraduallychanging.Asamethodofpurifyinganimpuritychemicalagents,separationonlysimpledistillationboilingpointhasalargedifference,suchastheboilingpointofthemainbodyofthedifferenceisgreaterthan50℃impurities.Toremoveimpuritieshavingaboilingpointoflessthan50deg.]Cwiththemaindifferenceis,willhavetouserectificationmethoddescribedbelow.

simpleatmosphericdistillationunitmainlyconsistsdistillationflask,thermometer,condenser,atrapandaheatingdevicewithasidetubeandothercomponents.Wheninstalled,themercurythermometershouldbeinsertedintotheballpositionlowerthanthesidetube,thesidetubeandacondenserconnectedtothedistillationflaskhorizontal,themouthandthecollectorconnectedtoacondenser(FIG.1).Whenusingadistillationapparatus,distilledaccordingtoboilingpointsoftheselectedtestchemicalheatingmeans:Thedistillationoftheliquidataboilingpointofless80℃,heatedwithhotwaterbath;liquidataboilingpointofabove100deg.]C,asbestosfireorbystraight-lineoilbath;liquidatatemperatureofabove200℃,heatingmetalbath.

distillationataboilingpointofabove150℃liquid,aircondensermaybeused.Inordertosmoothlycarryoutdistillation,andbeforeheating,thezeolitemustbeaddedaftertheliquidintheflaskchargedtotheflask.Becauseoftheverysmoothinnersurfaceoftheflask,andthebumpingpronetooverheating,sothatthedistillationcannotbecarriedoutsmoothly.Whenaddinganewzeolite,etc.mustAftercooledtoroomtemperaturebeforetheliquidwasaddedtotheflasktoavoidtheriskofboilingoccursabruptly.Zeoliteusedonlyonce,whentheliquidiscooled,addedtotheoriginalzeoliteloseseffect,sowhenthedistillationwascontinuedtobeaddedtothenewzeolite.Inatmosphericdistillation,havingaporous,easilycrushed,andthematerialwasdistilleddoesnotcausechemicalreactions,canbeusedasthezeolite.Zeolitesarecommonlycutinto1-2mmpiecesorunglazedclaytiles.

distillationapparatusisinstalled,theheatingcanbegin.Whenthesubstancebeginstoboilthedistillationflask,thetemperaturerisingsharply.Whenthetemperaturerisestotheboilingpointsubstanceweredistilleddown1℃,theintensityofheatingoftheheaterisadjustedtoalevelofadroppersecondeffluent.Inthiscase,theheatingtemperatureofthebathshouldbemaintainedathigherthantheboilingpointofthematerialinthedistillationflask20℃.Higherboilingmaterialdistillation,steamBeforei.e.lessthantheoutersidetubeandrefluxcoolingair,itcannotbedistilledoff.Atthistime,theflamecanbeuniformlyheatedusingamicrotubeofthelowersurfaceside,buttoavoidexcessiveheating,sothatthethermometerdoesnotindicatethecorrectboilingpoint,butalsoontheheatingportionoftheretortwithoutproperinsulation.Inthedistillationoperation,itshouldbenotedthefollowing:

(1)controltheheatingtemperature.Ifaheatingbath,thetemperatureoftheheatingbathshouldbeseveraldegreeshigherthantheboilingpointofthedistillationoftheliquid,otherwiseitisdifficulttobedistilledoutofthedistillate.Themoretheheatingbathtemperaturehigherthantheboilingpointoftheliquidofthedistillation,thedistillationfaster.However,thetemperatureoftheheatingbathcannotbetoohigh,otherwiseitwillleadtoanupperportionoftheretortandacondenservaporpressureaboveatmosphericpressure,anaccidentmayoccur,inparticular,moreparticularattentionduringdistillationlowboilers.Acamel,heatingbathtemperaturenothigherthantheboilingpointof30deg.]Cdistilledmaterial.

(2)distillingthehigh-boilingsubstances,condenseeasilybecause,oftendoesnotreachthevaporsideofthetube,i.e.thedistillationflaskhasbeencondenseddropsbackintothedistillationflask.Therefore,weshoulduseshort-neckedretortortakeinsulationmeasurestoensurethesmoothprogressofdistillation.

(3)priortothedistillation,thedistillationmustunderstandthechemicalagentandtheboilingpointandsaturatedvaporpressureimpurities,todeterminewhen(i.e.,atwhattemperature)tocollectpurechemicalagent.

(4)shallbeinthedistillationflaskroundbottomflask.

aboilingpointof40-150deg.]CmaybeemployedChemicalssimpledistillationundernormalpressure.Chemicalsforboilingatabove150℃oraboilingpointbelow150deg.]C,although,butthermallylabile,thermallydecomposingthechemicalagent,maybeemployedsteamdistillationandvacuumdistillation,simplybeintroducedseparately.

1.Simplevacuumdistillationapparatus,theentiresystemconsistsofKirschnerportion(aClaisen)distillationflask,condenser,accumulator,suction(vacuum)system,interfacesandothercomponents.Wheninstallingavacuumdistillationunit,itshouldbenotedthatthedeviceissealed,goodqualitycorkmustbeselectedslightlylargerthanthediameterofthestopperflask.Corkmaterialshouldbeselecteddependingonthenatureoftheliquidsamplevapor.Ifthesteamdoesnotcauseerosionoftherubberstopper,rubberstopperusingeasilyremainsealed.Whenyouuseagoodqualitymatteappliances,butalsoeasytoremainsealed.Afterthedeviceisinstalled,beforestartingthedistillation,thesealmustbecheckedtoreducedpressuredistillationapparatus.Sealingdeviceinspectionmethodisconfirmedbymeasurementofchangeinpressureofthesystem,andifthepressurevaluedoesnotchange,indicatingthedevicedoesnotleakbeforedistillationunderreducedpressure.Whendistillationunderreducedpressure,thecapillarytubemaybeinsertedinthedistillationflasktopreventbumpingphenomenon.Theupperendofthecapillarytubeissealed,thelowerendisopen.Checkthatthesealedairtightafterdistillation,thepurifiedchemicalreagenttobeaddedtotheflask,theflaskwasaddedinanamounthalfthevolume,andthesystemevacuatedtoareducedpressurestate,andheatingisstarted.Theflaskwasimmersedinaheatingbathdepth,tobesurethatthebottleisbelowtheliquidsurfacelevelofsubstancedistilledheatingbath.Especiallyinahigh-boilingmaterialdistillation,theflaskwasimmerseddeepershouldtry.Whendistillationunderreducedpressure,oftenduetothepresenceoflowboilingsolventtoproduceafoam,requirealowdegreeofvacuumintheselow-boilingsolventwasdistilledoffbydistillationatthebeginning,andthengraduallyincreasethedegreeofvacuum.Lowvaporpressuredependsonthedegreeofvacuumoftheapparatusoftheliquidsample.Beforecoolingeffectmustbewelldistillates,otherwiseitisdifficulttoincreasethevacuumsystem.

Relationshipbetweenpressureandboilingpoint,canbeapproximatedoutbythefollowingformulaisderived:logP=A+(B/T)

whereinPisthevaporpressure,Tistheabsolutetemperature,A,Bisaconstant.Inpractice,theboilingpointcanbefoundinrelatedstressFIG.Whenthedistillationiscompletedistillationboilingpointcomponentsdesired,orwhenthedistillationprocessneedstobeinterrupted,heatingshouldbestopped,theheatingbathwasremoved,andaftercooling,slowlyreleasingthevacuumsystem,theapparatustoallowairtoenterthenormalpressureoffthevacuumpump.

steamdistillationistheseparationandpurificationmethodscommonlyusedinorganicmattersample,especiallyinthepresenceofalargenumberofresinousimpuritiesinthesampleupon.Thesamplewastreatedcompositionshouldmeetthefollowingconditions:thatisinsolubleoralmostinsolubleinwater,withboilingwaterduringprolongedcoexistencenochemicalchange,musthaveavaporpressureunderconditionsofgreaterthanabout100℃of10mmHg.

steamdistillation,isanothertechniqueforproducingheat-sensitivesamplesandforpurification.Itcanalsobeusedforgoodheattransferliquidsample,willdirectlycauselocaloverheatingheating.Steamdistillationmaybecompletedbycontinuouslysteamflowsthroughthevesselinthesamplemixture.Sometimestheuserdirectlyintotheflaskwithwaterforthesamepurpose.Steamcarryinggasphasevolatilecomponentandsuchalargeconcentratedvolatilematerialrelatedtotheirvaporpressureinthevapormixtureinthevapormixture.

Thistechniqueisverymild,duringthedistillationwillnotbedistilledmaterialisheatedtohigherthanthetemperatureofthesteam.Attheendoftheprocess,thesteamiscondensedandseparatedmaterial.Typically,theyareimmiscibleandmayformtwophasesareseparated.Sometimesanalyticalchemistmusthaveanadditionalsamplepreparationtechnique,suchasfluid-tocompletelyseparateaqueousandorganiclayersmultipleliquidextraction.

2.Simplemeansofsteamdistillation,Asteamgeneratoris,asthelevelgaugeglassBcanbeseenthattheheightofthewatersurfaceoccurs.Shengwaterisgenerallyappropriatecontainervolumeof75%,iftoofull,boilingwaterrushedtotheflask.SafetyglasstubeCisalmostinsertedinthebottomofthegeneratorA.Whenthepressureinsidethecontaineristoolarge,thewatercanrisealongtheglasstube,inordertoadjusttheinnerpressure.Ifthesystemisclogged,thewaterwillbeejectedfromtheupperopeningofthetube,itshouldbecheckedatthistimethesteamconduitundertheroundbottomflaskwhethertheportisblocked.Usingtheaboverectifyingpartgenerallynecked500mlroundbottomflask.Inordertopreventtheliquidinthebottleduetosplashjumpintothecondensertubes,sothatthepositionoftheflaskwastiltedby45degreesinthedirectionofthegenerator.Bottleofliquidsampleshouldnotexceed1/3ofitsvolume.EndofthesteamintroducingpipetobebentE,itisontheverticallyoutintothebottomofthebottleandclosethecentralbottom.SteamoutletpipeF(approximately30°angled)innerdiameterEispreferablylargerthanthenumberoftubes,insertoneendofthecorkwithtwoholes,exposingapproximately5mm,andtheotherendconnectedtothecondenser.DistillateliquidpipeintothereceptaclethroughtheaccessH.Availablewaterbathcoolingtheperipheralreceptacle.

inthesteamgeneratorandtheneckedroundbottomflaskshouldbeinstalledbetweenaT-shapedpipe,connectedatthelowerendofaT-piecespringclipG,inordertotimelyremovecondensedwaterdropletsclogging.When

steamdistillation,firstthesamplesolutionwasplacedinD.HeatingthesteamgeneratortonearboilinguntilaftertheGintensifythesteamevenlyintotheroundbottomflask.InordernottocondensethesteamandexcessiveaccumulationofD,itcanbesetatanetasbestosD,ifnecessary,tomakesmallflame.Heatingratemustbecontrolledsothatallthesteamcanbecondensedinthecondenser.Ifthevolatilesubstancewithwaterhavingahighermeltingpointvaporcondensedinthesolidwaseasilyprecipitated,itshouldadjusttheflowrateofthesmallcondensateaftercondensingitremainsliquid.Ifthesolidhasprecipitated,andthenearclogging,temporarilystopstheflowofcoolingwater,coolingwaterisevennecessarytotemporarilyletgo,sothatthemeltedmaterialflowsintothereceptaclewiththewater.Itmustbenoted,whenthecondensertobere-introducedintothejacketcoolingwater,needtobecarefullyandslowlyflowsinto,topreventquenchingduetorupturecondenser.Casehasbeenblockedcondenser,distillationwasstoppedimmediately,andtrytoclear.Suchasusingaglassrodtopokeoutorcloggingofmaterialtothehotwaterinacondensersoastomeltthetankjacket.

duringdistillationifitbreaksordistillationwascomplete,thespringclipmustfirstopenthethroughGatmosphere,thenheatingwasstopped,ortheliquidsuckedD,A,willbeinverted.Duringthedistillation,thewaterlevelrisesrapidlyiffoundsafeintubeC,thencloggingoccursinthesystem,thenitshouldimmediatelyopenthespringclipG,andthentheheatwasremoved.Beexcludedbeforecontinuingpluggingsteamdistillation.

III.Rectification

fractionaldistillationiscarriedoutbyfractionaldistillationcolumninthedistillationprocess,thechemicalagentisrectifiedinthedistillationflaskafterboiling,thesteamfromthegardenbottomflaskevaporatesintoafractionatingcolumn,condensedinthefractionatingcolumnintoaliquidportion.Theliquidduetohighcontentoflow-boilingcomponents,andthereforealsolowerthantheboilingpointoftheliquidtemperatureinthedistillationflask.Whenthedistillationflasktoanotherportionofthevaporrisesinthefractionationcolumn,andthentheliquidhascondensedbyheatexchange,re-boilingit,whiletheascendingvaporispartiallycondensedinitself,andtherefore,ithasproducedanewtheliquid-vaporequilibrium,theresultsofthelow-boilingcomponentinthevaporhaveincreased.Whenthenewvaporriseswithinthedistillationcolumn,andiscondensedintoaliquid,andthenbyheatexchangewithanotherportionoftheascendingvaporboils.Duetoconstantlyascendingvaporcondensationandevaporationfractionatingthecolumn,andeachtimebothevaporationandcondensationofthesteaminthelow-boilingcomponentcontinuestoincrease.Accordingly,duringascentofsteaminthefractionatingcolumn,similarlyrepeatedaftersimpledistillationofthelowboilingcomponentthevaporgraduallyincrease.Thus,inthefractionationprocessiscriticaldephlegmatorapparatus,ifappropriateselectedfractionatingcolumncancomeoutatthetopofthefractionatingcolumnvaporcondensedandtheresultingliquidmaybeapurecomponentoralow-boilinglow-boilingaccountedeffluentmaincomponent.

fractionationcapacityandefficiencyofthefractionationcolumn,respectively,as"theoreticalplatesvalue"and"heightequivalenttheoreticalplate(theHETP)"represented.Avalueequivalenttoatheoreticalplatesimpledistillation.Thedistillationcolumnhavingafractionatingcapabilityofthesame,whichisnotnecessarilyequallength.Forexample:A,Btwodephlegmator,theirvalues​​are20theoreticalplates,Aistheheightof60cmandaheightof20cmacetate.Obviously,boththeoreticalplateheightequivalentisdifferent.Becausetheheightequivalentoftheoreticalplate:

HETP=heightofthedistillationcolumn/theoreticalplatenumber

Therefore,theoreticalplatesAfractionatingcolumnheightequivalentof3cm,andacetatetheoreticalplatesfractionatingcolumnheightequivalentof1cm.Itcanbeseenthroughthisexample,theequivalentoftheoreticalplatesofthedistillationcolumnheightislower,thehigheritsefficiencyinfractionationunitlength.

Duringdistillationoperation,themainfractionatingcolumnselectedaccordingtotheleveldifferencebetweentheboilingpointandtheboilingpointofthechemicalagentintherectificationbodywithimpurities.Ifthedifferenceinboilingpointinthetwocomponentsabove100℃,afractionatingcolumnmaynotbeused;iftheboilingpointdifferenceisabout25℃,optionallyconventionalfractionatingcolumn;iftheboilingpointdifferenceisabout10℃,requireselaboratefractionatingcolumn,suchasmicro-Grofractionatingcolumnandthelike.Distillationprocessusingtheheatsourcemustbestabletoensureaheatingtemperaturestable.Onlystrictcontrolandconstantheatinginordertomaintainthedesiredrefluxratio.Ifheatedtooquickly,willproducefloodingphenomenon,thefractionationefficiencyispoor.Iftheheatingistooslow,youcanonlyplaytheroleofafractionatingcolumnrefluxcondenser,simplydistilledoutanything.Further,atthetimeofdistillation,refluxanddistillaterequiresanappropriateratio,i.e.refluxratioshouldbeappropriate,itsvalueisequaltothevalueoftheoreticalplatesfractionatingcolumnsubstantiallyso,tomakethenormaldistillationprocess.

IV.Thepracticalapplicationofdistillationandrectification

distillationandrectificationmainlyusedforliquidorheatingliquidcanbeachemicalagent,inparticularfororganicchemicalspurification.Priortodistillationorrectification,sometimestheadditionofcertainchemicalreagents,chemicalreactionwithachemicalreagenttobepurifiedofimpuritiesoccurs,generatingahigherboilingpoint(orless)substance,ismoreeasilyremovedinadistillationorrectification.

duringdistillationorrectification,isoftenthefirstdistillatefractionisremovedandthefinalremainingfraction,twoofthemoreremoved,thehigherthepurityofthechemicalagent,buttheloweryields.