Hauv kev lag luam tshuaj lom neeg, muaj ob yam khoom uas muaj lub npe zoo sib xws, uas yog glyoxylic acid thiab glycolic acid. Feem ntau cov neeg tsis paub meej tias lawv sib txawv li cas. Niaj hnub no, cia peb saib ob yam khoom no ua ke. Glyoxylic acid thiab glycolic acid yog ob hom organic compounds uas muaj qhov sib txawv ntawm cov qauv thiab cov khoom. Lawv qhov sib txawv feem ntau yog nyob rau hauv cov qauv molecular, cov khoom siv tshuaj, cov khoom siv lub cev thiab cov ntawv thov, raws li nram no:
Cov qauv molecular thiab cov khoom sib xyaw ua ke sib txawv
Qhov no yog qhov sib txawv tseem ceeb tshaj plaws ntawm ob qho no, uas txiav txim siab ncaj qha rau qhov sib txawv ntawm lwm yam khoom.
CAS 298-12-4, nrog rau cov tshuaj lom neeg C2H2O3 thiab cov qauv HOOC-CHO, muaj ob pawg ua haujlwm - pawg carboxyl (-COOH) thiab pawg aldehyde (-CHO), thiab yog cov aldehyde acid chav kawm ntawm cov tshuaj.
CAS 79-14-1, nrog rau cov tshuaj lom neeg C2H4O3 thiab cov qauv HOOC-CH2OH, muaj ob pawg ua haujlwm - pawg carboxyl (-COOH) thiab pawg hydroxyl (-OH), thiab koom nrog α-hydroxy acid chav kawm ntawm cov tshuaj.
Cov qauv molecular ntawm ob qho sib txawv los ntawm ob lub hydrogen atoms (H2), thiab qhov sib txawv ntawm cov pab pawg ua haujlwm (aldehyde pab pawg vs. hydroxyl pab pawg) yog qhov sib txawv tseem ceeb.
Cov khoom siv tshuaj sib txawv
Qhov sib txawv ntawm cov pab pawg ua haujlwm ua rau muaj cov khoom sib txawv kiag li ntawm ob qho no:
Cov yam ntxwv ntawmglyoxylic acid(vim muaj cov pab pawg aldehyde):
Nws muaj cov khoom txo qis muaj zog: pawg aldehyde yooj yim oxidized thiab tuaj yeem dhau los ua cov tshuaj tiv thaiv iav nyiaj nrog cov tshuaj ammonia nyiaj, tshuaj tiv thaiv nrog cov tooj liab hydroxide tshiab los tsim cov av nplaum liab (cuprous oxide), thiab tseem tuaj yeem oxidized rau oxalic acid los ntawm cov oxidants xws li potassium permanganate thiab hydrogen peroxide.
Cov pab pawg aldehyde tuaj yeem dhau los ntawm kev sib ntxiv: piv txwv li, lawv tuaj yeem cuam tshuam nrog hydrogen los tsim glycolic acid (qhov no yog ib hom kev hloov pauv ntawm ob qho).
Cov yam ntxwv ntawm glycolic acid (vim muaj cov pab pawg hydroxyl):
Cov pab pawg Hydroxyl yog nucleophilic: lawv tuaj yeem dhau los ntawm kev sib xyaw ua ke lossis intermolecular esterification reactions nrog carboxyl pab pawg los tsim cov cyclic esters lossis polyesters (xws li polyglycolic acid, cov khoom siv polymer uas lwj tau).
Cov pab pawg hydroxyl tuaj yeem raug oxidized: txawm li cas los xij, qhov nyuaj oxidation siab dua li ntawm cov pab pawg aldehyde hauv glyoxylic acid, thiab cov tshuaj oxidant muaj zog dua (xws li potassium dichromate) yog qhov xav tau los oxidize cov pab pawg hydroxyl rau cov pab pawg aldehyde lossis cov pab pawg carboxyl.
Qhov acidity ntawm pawg carboxyl: Ob leeg muaj cov pawg carboxyl thiab yog acidic. Txawm li cas los xij, pawg hydroxyl ntawm glycolic acid muaj qhov tsis muaj zog electron-donating effect rau pawg carboxyl, thiab nws cov acidity yog me ntsis qaug zog dua li ntawm glycolic acid (glycolic acid pKa≈3.18, glycolic acid pKa≈3.83).
Cov khoom sib txawv ntawm lub cev
Lub xeev thiab solubility:
Yooj yim yaj hauv dej thiab cov kuab tshuaj polar organic (xws li ethanol), tab sis vim muaj qhov sib txawv ntawm molecular polarity, lawv cov solubility txawv me ntsis (glyoxylic acid muaj polarity muaj zog dua thiab solubility siab dua me ntsis hauv dej).
Qhov kub yaj
Lub ntsiab lus yaj ntawm glyoxylic acid yog kwv yees li 98 ℃, thaum glycolic acid yog li 78-79 ℃. Qhov sib txawv yog los ntawm cov zog intermolecular (pawg aldehyde ntawm glyoxylic acid muaj peev xwm ua tau hydrogen bonds nrog pawg carboxyl).
Daim ntawv thov sib txawv
Nws feem ntau yog siv rau hauv kev lag luam organic synthesis, xws li kev tsim cov vanillin (tshuaj tsw qab), allantoin (ib qho tshuaj nruab nrab rau kev txhawb nqa kev kho qhov txhab), p-hydroxyphenylglycine (ib qho tshuaj tua kab mob nruab nrab), thiab lwm yam. Nws kuj tseem siv tau ua ib qho khoom ntxiv rau hauv cov tshuaj electroplating lossis hauv cov tshuaj pleev ib ce (siv nws cov khoom txo thiab antioxidant). Cov khoom saib xyuas plaub hau: Ua ib qho khoom xyaw conditioning, nws pab kho cov plaub hau puas thiab txhim kho cov plaub hau ci ntsa iab (yuav tsum tau ua ke nrog lwm cov khoom xyaw kom txo qhov khaus).
Ua ib qho α-hydroxy acid (AHA), nws daim ntawv thov tseem ceeb yog nyob rau hauv thaj chaw ntawm cov khoom saib xyuas tawv nqaij. Nws ua haujlwm ua cov khoom xyaw exfoliating (los ntawm kev yaj cov khoom sib txuas ntawm stratum corneum ntawm daim tawv nqaij los txhawb kev tshem tawm ntawm cov tawv nqaij tuag), txhim kho cov teeb meem xws li daim tawv nqaij ntxhib thiab cov cim pob txuv. Tsis tas li ntawd, nws kuj siv rau hauv kev lag luam textile (ua tus neeg sawv cev dawb), cov neeg sawv cev ntxuav (rau kev tshem tawm cov nplai), thiab hauv kev tsim cov yas lwj (polyglycolic acid).
Qhov sib txawv tseem ceeb ntawm ob hom no yog los ntawm cov pab pawg ua haujlwm: glyoxylic acid muaj ib pawg aldehyde (nrog cov khoom txo qis muaj zog, siv rau hauv kev tsim cov organic), thiab glycolic acid muaj ib pawg hydroxyl (tuaj yeem esterified, siv rau hauv kev saib xyuas tawv nqaij thiab cov ntaub ntawv). Los ntawm cov qauv mus rau qhov xwm txheej thiab tom qab ntawd mus rau kev siv, lawv txhua tus qhia txog qhov sib txawv tseem ceeb vim yog qhov sib txawv tseem ceeb no.
Lub sijhawm tshaj tawm: Lub Yim Hli-11-2025