izindaba

Embonini yamakhemikhali, kunemikhiqizo emibili enamagama afana kakhulu, okuyi-glyoxylic acid kanye ne-glycolic acid. Abantu bavame ukungakwazi ukuhlukanisa. Namuhla, ake sibheke le mikhiqizo emibili ndawonye. I-Glyoxylic acid kanye ne-glycolic acid kuyizinhlanganisela ezimbili eziphilayo ezinomehluko omkhulu ekwakhiweni kanye nezakhiwo. Umehluko wazo ulele kakhulu esakhiweni sama-molecule, izakhiwo zamakhemikhali, izakhiwo zomzimba kanye nokusetshenziswa, kanje:

Isakhiwo sama-molecule kanye nokwakheka kwawo kuhlukile

Lona umehluko obaluleke kakhulu phakathi kwalokhu okubili, okunquma ngqo umehluko kwezinye izakhiwo.

I-Glyoxylic acid

I-CAS 298-12-4, enefomula yamakhemikhali i-C2H2O3 kanye nefomula yesakhiwo i-HOOC-CHO, iqukethe amaqembu amabili asebenzayo - iqembu le-carboxyl (-COOH) kanye neqembu le-aldehyde (-CHO), futhi liyingxenye yesigaba se-aldehyde acid samakhemikhali.

I-Glycolic acid

I-CAS 79-14-1, enefomula yamakhemikhali i-C2H4O3 kanye nefomula yesakhiwo i-HOOC-CH2OH, iqukethe amaqembu amabili asebenzayo - iqembu le-carboxyl (-COOH) kanye neqembu le-hydroxyl (-OH), futhi liyingxenye yekilasi lama-compounds e-α-hydroxy acid.

Amafomula ama-molecule alawa amabili ahluka ngama-athomu amabili e-hydrogen (H2), futhi umehluko emaqenjini asebenzayo (iqembu le-aldehyde vs. iqembu le-hydroxyl) uwumehluko oyinhloko.

Izakhiwo zamakhemikhali ezahlukene

Umehluko emaqenjini asebenzayo uholela ezicini zamakhemikhali ezihluke ngokuphelele phakathi kwalezi ezimbili:

Izici zei-glyoxylic acid(ngenxa yokuba khona kwamaqembu e-aldehyde):

Inezakhiwo eziqinile zokunciphisa: iqembu le-aldehyde liqiniswa kalula futhi lingabhekana nokusabela kwesibuko sesiliva nesisombululo se-ammonia sesiliva, lisabela ngokumiswa kwe-copper hydroxide okusanda kulungiswa ukuze kwakheke i-precipitate ebomvu-isitini (i-cuprous oxide), futhi lingaqiniswa libe yi-oxalic acid ngama-oxidants afana ne-potassium permanganate ne-hydrogen peroxide.

Amaqembu e-Aldehyde angabhekana nokusabela okwengeziwe: isibonelo, angasabela ne-hydrogen ukuze akhe i-glycolic acid (lolu uhlobo lobuhlobo bokuguqulwa phakathi kwalokhu okubili).

Izici ze-glycolic acid (ngenxa yokuba khona kwamaqembu e-hydroxyl):

Amaqembu e-hydroxyl aphila nge-nucleophilic: angabhekana nokusabela kwe-intramolecular noma intermolecular esterification namaqembu e-carboxyl ukuze akhe ama-ester noma ama-polyester ajikelezayo (njenge-polyglycolic acid, into ebolayo ye-polymer).

Amaqembu e-hydroxyl angaxutshwa: noma kunjalo, ubunzima be-oxidation buphakeme kunobamaqembu e-aldehyde ku-glyoxylic acid, futhi kudingeka i-oxidant enamandla (njenge-potassium dichromate) ukuze kuxutshwe amaqembu e-hydroxyl abe amaqembu e-aldehyde noma amaqembu e-carboxyl.

Ubumuncu beqembu le-carboxyl: Zombili ziqukethe amaqembu e-carboxyl futhi zine-asidi. Kodwa-ke, iqembu le-hydroxyl le-glycolic acid linomphumela obuthakathaka wokunikela ngama-electron eqenjini le-carboxyl, futhi ubumuncu balo bubuthakathaka kancane kunobe-glycolic acid (i-glycolic acid pKa≈3.18, i-glycolic acid pKa≈3.83).

Izakhiwo ezihlukile zomzimba

Isimo kanye nokuncibilika:

Incibilika kalula emanzini kanye nasezithambisweni eziphilayo ezi-polar (njenge-ethanol), kodwa ngenxa yomehluko ku-polarity yama-molecule, ukuncibilika kwawo kuhlukile kancane (i-glyoxylic acid ine-polarity enamandla kanye nokuncibilika okuphezulu kancane emanzini).

Indawo yokuncibilika

Iphuzu lokuncibilika kwe-glyoxylic acid licishe libe ngu-98℃, kanti ele-glycolic acid licishe libe ngu-78-79℃. Umehluko uvela emandleni aphakathi kwama-molecule (iqembu le-aldehyde le-glyoxylic acid linamandla aqinile okwakha izibopho ze-hydrogen neqembu le-carboxyl).

Isicelo esihlukile

I-Glyoxylic acid

Isetshenziswa kakhulu embonini yokwenziwa kwezinto eziphilayo, njengokwenziwa kwe-vanillin (ukunambitheka), i-allantoin (isidakamizwa esikhuthaza ukuphulukiswa kwamanxeba), i-p-hydroxyphenylglycine (isidakamizwa esilwa namagciwane), njll. Ingasetshenziswa futhi njengesithasiselo ezixazululweni ze-electroplating noma ezimonyweni (kusetshenziswa izakhiwo zayo zokunciphisa kanye nezokulwa namagciwane). Imikhiqizo yokunakekelwa kwezinwele: Njengesithako sokulungisa izinwele, isiza ukulungisa imicu yezinwele eyonakele futhi ithuthukise ukukhazimula kwezinwele (kudingeka kuhlanganiswe nezinye izithako ukunciphisa ukucasuka).

I-Glycolic acid

Njenge-α-hydroxy acid (AHA), ukusetshenziswa kwayo okuyinhloko kusemkhakheni wemikhiqizo yokunakekelwa kwesikhumba. Isebenza njengesithako sokukhipha amabala (ngokuqeda izinto ezixhumanisayo phakathi kwe-stratum corneum yesikhumba ukukhuthaza ukukhishwa kwesikhumba esifile), ukuthuthukisa izinkinga ezifana nesikhumba esiqinile kanye namabala esikhumba. Ngaphezu kwalokho, isetshenziswa futhi embonini yezindwangu (njenge-bleaching agent), izinto zokuhlanza (zokususa isikali), kanye nokuhlanganiswa kwamapulasitiki abolayo (i-polyglycolic acid).

Umehluko oyinhloko phakathi kwalezi ziqu ezimbili ezivela emaqenjini asebenzayo: i-glyoxylic acid iqukethe iqembu le-aldehyde (elinezici zokunciphisa ezinamandla, ezisetshenziswa ekwakhiweni kwezinto eziphilayo), kanti i-glycolic acid iqukethe iqembu le-hydroxyl (lingaqinisekiswa, lisetshenziswe emikhakheni yokunakekelwa kwesikhumba kanye nezinto zokwakha). Kusukela esakhiweni kuya emvelweni bese kuba ukusetshenziswa, konke kubonisa umehluko omkhulu ngenxa yalo mehluko oyinhloko.