Oxalic acid

Reserve carboxylic diacid nrog tag nrho cov mis C2H2O4 hu ua los ntawm systematic nomenclature ethanedioic acid. Qhov no compound kuj yog paub los ntawm lwm yam ntau ntau lub npe - oxalic acid. Nws twb xub ua los ntawm cov German chemist F. Wohler ntawm cyanogen (oxalic acid dinitrile) nyob rau hauv 1824. Tsis muaj kob muaju ntawm lub acid yaj nyob rau hauv dej rau tsis muaj kob daws teeb meem. hniav puas luj yog 90,04 g / mol. Nyob rau hauv tsos tsa monoclinic tsis muaj kob muaju. Nyob rau hauv 20 ° C nyob rau hauv 100 g ntawm dej twb yaj 8 g ntawm oxalic acid. Soluble nyob rau hauv acetone, ethanol thiab ethyl ether. Ceev 1.36 g / cm³. Melts ntawm 189,5 ° C, sublimes ntawm 125 ° C, decomposes ntawm 100-130 ° C.

Tag nrho cov tshuaj zog yam ntxwv ntawm lub carboxylic acids, oxalic acid muaj. Formula nws: HOOC-COOH. Txawm tias muaj tseeb hais tias yog hais txog carboxylic acids yog suav tias yog ib tug muaj zog organic acid (3000 lub sij hawm muaj zog tshaj acetic acid): C2O4H2 → C2O4H- + H + (pKa = 1.27) thiab ntxiv: C2O4H- → C2O42 - + H + (PK = 4.27). Esters thiab ntsev ntawm no acid yog hu ua oxalate. C2O42- oxalate ion yog ib tug txo neeg sawv cev. Nyob rau hauv cov tshuaj tiv thaiv ntawm oxalic acid nrog ib tug tov ntawm poov tshuaj permanganate (KMnO4) thiab rau tom kawg yog zoo tu qab tso tshuaj yuav tsis muaj kob. Nws yog yus muaj los ntawm cov tshuaj tiv thaiv reversible thiab maj mam ntws tshuaj tiv thaiv uas alcohols (esterification) raws li ib tug tshwm sim ntawm uas tus esters yog tsim: HOOC-COOH + 2HOR ↔ 2H2O + ROOC-COOR.

Nyob rau hauv kev lag luam, oxalic acid, tau los ntawm oxidation ntawm cov tshuaj tebchaw. Piv txwv li, nyob rau hauv lub xub ntiag ntawm ib tug vanadium catalyst (V2O5) sib tov ntawm nitric acid (HNO3) thiab sulfuric (H2SO4) acids oxidize alcohols, glycols thiab carbohydrates. Tsis tas li ntawd tsis tsim txoj kev ethylene thiab acetylene oxidation nrog nitric acid (HNO3) nyob rau hauv lub xub ntiag ntawm palladium ntsev ntawm Pls (NO3) 2 los yog PdCl2. Oxalic acid yog tau los ntawm propylene, kua uas yog oxidized los ntawm nitrogen dioxide (NO2). Nws muaj ib tug zoo prospect txheej txheem npaj cov tshuaj tiv thaiv ntawm lub acid nrog sodium hydroxide (NaOH) nrog cov pa roj carbon monoxide (CO) los ntawm lub intermediate theem ntawm tsim ntawm sodium formate: NaOH + CO → HCOONa. Ces tus tsim sodium oxalate thiab hydrogen yog tso tawm: HCOONa + NaOH → NaOOC-COONa + H2 ↑. Ntawm sodium oxalate nyob rau hauv ib tug acidic puag ncig tau oxalic acid: NaOOC-COONa + 2H + → HOOC-COOH + 2Na +.

Main daim ntaub ntawv ntawm oxalic acid - ib tug tu los yog ntxuav hniav dawb. Oxalic acid yuav zoo tshem tawm xeb, thiaj li muaj ntau tu txhais tau tias comprise ib tug tshuaj compound. Hais txog ib tug peb lub hlis twg ntawm oxalic acid ua yog siv raws li ib tug mordant rau dyeing daim tawv thiab textile industries. Nws kuj yuav siv tau raws li ib tug reagent (GOST 22180-76) nyob rau hauv analytical Science News for KIDS. Etandioevaya acid dihydrate (HOOC-COOH • H2O) TU 2431-002-77057039-2006 nrog ib tug loj feem ntawm qhov yooj yim tshuaj ≥ 99,3% yog siv nyob rau hauv lub dab ntau lawm ntawm cov organic synthesis rau lub purification ntawm xeb thiab scale hlau rau tshuaj dawb tso ib tug sectioning microscopy. Beekeepers siv oxalic acid tov nrog ib tug loj feem ntawm 3.2% nyob rau hauv qab zib phoov rau combating ib tug cab xu. Tomqab kawm tas marble lug nws saum npoo kho yuav muab thiab muab lawv glints.

Oxalic acid thiab oxalates tam sim no nyob rau hauv ntau cov nroj tsuag, nrog rau cov dub tshuaj yej, yog pom nyob rau hauv cov tsiaj. Lub ntsiab kev puas tsuaj rau cov tib neeg yog txuam nrog lub raum tsis ua hauj lwm, uas tshwm sim vim tus sis ntawm oxalic acid uas muaj calcium, ua nyob rau hauv lub nag lossis daus cov khoom calcium oxalate (SaS2O4) - lub ntsiab tivthaiv nyob rau hauv lub raum pob zeb. Acid provokes mob tej pob txha vim nag lossis daus ntawm xws tebchaw nyob rau hauv lawv. Oxalic acid peev xwm yuav tsim nyob rau hauv lub cev los ntawm cov metabolism hauv ethylene los ntawm cov ib puag ncig (e.g., anti-icing txhais tau rau cov zauv rau lub runways ntawm tshav dav hlau thiab dav hlau, raws li zoo raws li lwm tus txiv neej-ua qhov chaw). Tej zaum muaj teeb meem nrog oxalate nyob rau hauv tib neeg lub cev yuav tsum tau muab faib ua ob. Thawj - ib qho tseem ceeb macrocell calcium uake oxalic acid thiab nws tsis muaj peev xwm yog tsim nyob rau hauv lub hlwb ntawm ntaub so ntswg thiab kabmob. Qhov thib ob - tus tsim ntawm raum pob zeb. Qhov loj tshaj npaum li cas ntawm oxalic acid muaj nyob rau hauv spinach nplooj thiab stems ntawm rhubarb, sorrel, beets, zaub txhwb qaib, scallions.