Hauv kev lag luam tshuaj, muaj ob yam khoom uas muaj npe zoo sib xws, uas yog glyoxylic acid thiab glycolic acid. Tib neeg feem ntau tsis tuaj yeem qhia lawv sib nrug. Niaj hnub no, cia peb saib ob yam khoom no ua ke. Glyoxylic acid thiab glycolic acid yog ob lub tebchaw organic nrog qhov sib txawv tseem ceeb hauv cov qauv thiab cov khoom. Lawv qhov txawv tsuas yog nyob rau hauv cov qauv molecular, tshuaj muaj zog, lub cev thiab kev siv, raws li hauv qab no:
Cov qauv molecular thiab muaj pes tsawg leeg sib txawv
Qhov no yog qhov tseem ceeb tshaj qhov sib txawv ntawm ob, uas ncaj qha txiav txim siab qhov sib txawv ntawm lwm yam khoom.
CAS 298-12-4, nrog cov tshuaj formula C2H2O3 thiab cov qauv qauv HOOC-CHO, muaj ob pawg ua haujlwm - pawg carboxyl (-COOH) thiab pawg aldehyde (-CHO), thiab belongs rau aldehyde acid chav kawm ntawm cov tebchaw.
CAS 79-14-1, nrog cov tshuaj formula C2H4O3 thiab cov qauv qauv HOOC-CH2OH, muaj ob pawg ua haujlwm - pawg carboxyl (-COOH) thiab pawg hydroxyl (-OH), thiab belongs rau α-hydroxy acid chav kawm ntawm cov tebchaw.
Cov qauv molecular ntawm ob qhov sib txawv los ntawm ob lub hydrogen atoms (H2), thiab qhov sib txawv ntawm pawg ua haujlwm (aldehyde pawg vs. hydroxyl pawg) yog qhov sib txawv ntawm cov tub ntxhais kawm.
Cov khoom siv tshuaj sib txawv
Qhov sib txawv ntawm cov pab pawg ua haujlwm ua rau muaj cov tshuaj lom neeg sib txawv ntawm ob:
Yam ntxwv ntawmglyoxylic acid(vim muaj cov pab pawg aldehyde):
Nws muaj zog txo cov khoom: cov aldehyde pawg tau yooj yim oxidized thiab tuaj yeem ua rau cov iav nyiaj siv tshuaj tiv thaiv nrog cov tshuaj ammonia, hnov mob nrog cov txheej txheem tshiab ntawm tooj liab hydroxide ncua kev kawm los tsim cov cib-liab precipitate (cuprous oxide), thiab tuaj yeem oxidized rau oxalic acid los ntawm oxidants xws li poov tshuaj permanganate thiab hydrogen peroxide.
Cov pab pawg Aldehyde tuaj yeem ua rau muaj kev cuam tshuam ntxiv: piv txwv li, lawv tuaj yeem hnov mob nrog hydrogen los tsim glycolic acid (qhov no yog hom kev hloov pauv kev sib raug zoo ntawm ob).
Cov yam ntxwv ntawm glycolic acid (vim muaj cov pab pawg hydroxyl):
Hydroxyl pawg yog nucleophilic: lawv tuaj yeem nkag mus rau intramolecular lossis intermolecular esterification cov tshuaj tiv thaiv nrog carboxyl pawg los tsim cyclic esters lossis polyesters (xws li polyglycolic acid, cov khoom siv polymer degradable).
Hydroxyl pawg tuaj yeem oxidized: Txawm li cas los xij, qhov nyuaj oxidation yog siab dua li pawg aldehyde hauv glyoxylic acid, thiab cov oxidant muaj zog (xws li potassium dichromate) yuav tsum tau oxidize hydroxyl pawg rau aldehyde pawg lossis carboxyl pawg.
Cov acidity ntawm carboxyl pawg: Ob leeg muaj carboxyl pawg thiab yog acidic. Txawm li cas los xij, pawg hydroxyl ntawm glycolic acid muaj qhov tsis muaj zog electron-pab cuam tshuam rau pawg carboxyl, thiab nws cov acidity me ntsis qis 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 soluble hauv dej thiab polar organic solvents (xws li ethanol), tab sis vim qhov sib txawv ntawm molecular polarity, lawv cov solubilities txawv me ntsis (glyoxylic acid muaj zog polarity thiab me ntsis dua solubility hauv dej).
Melting point
Lub melting point ntawm glyoxylic acid yog kwv yees li 98 ℃, thaum glycolic acid yog li 78-79 ℃. Qhov sib txawv stems los ntawm intermolecular rog (cov aldehyde pawg ntawm glyoxylic acid muaj zog muaj peev xwm tsim hydrogen bonds nrog cov carboxyl pawg).
Daim ntawv thov sib txawv
Nws yog tsuas yog siv nyob rau hauv cov organic synthesis kev lag luam, xws li cov synthesis ntawm vanillin (flavoring), allantoin (ib tug kws intermediate rau kev txhawb lub qhov txhab zoo), p-hydroxyphenylglycine (ib tug tshuaj tua kab mob nruab nrab), thiab lwm yam. Nws kuj yuav siv tau raws li ib tug additive nyob rau hauv electroplating kev daws teeb meem los yog nyob rau hauv cov tshuaj pleev ib ce (kev noj qab haus huv zog). Cov khoom tu plaub hau: Raws li cov khoom siv kho mob, nws pab kho cov plaub hau puas thiab txhim kho cov plaub hau luster (yuav tsum tau ua ke nrog lwm cov khoom xyaw kom txo tau qhov khaus).
Raws li ib qho α-hydroxy acid (AHA), nws daim ntawv thov tseem ceeb yog nyob rau hauv kev lag luam ntawm cov khoom tu tawv nqaij. Nws ua hauj lwm pab raws li ib tug exfoliating ingredient (los ntawm dissolving cov khoom sib txuas ntawm lub stratum corneum ntawm daim tawv nqaij los txhawb lub shedding ntawm cov tawv nqaij tuag), txhim kho cov teeb meem xws li tawv tawv thiab pob txuv. Tsis tas li ntawd, nws kuj tseem siv rau hauv kev lag luam textile (raws li tus neeg sawv cev bleaching), tshuaj ntxuav (rau tshem tawm cov nplai), thiab hauv kev sib txuas ntawm cov yas degradable (polyglycolic acid).
Qhov sib txawv tseem ceeb ntawm ob lub stems los ntawm cov pab pawg ua haujlwm: glyoxylic acid muaj cov pab pawg aldehyde (nrog rau cov khoom txo qis, siv hauv cov organic synthesis), thiab glycolic acid muaj cov pab pawg hydroxyl (tuaj yeem ua esterified, siv hauv kev tu tawv nqaij thiab cov khoom siv). Los ntawm cov qauv mus rau xwm thiab tom qab ntawd mus rau daim ntawv thov, lawv txhua tus pom qhov sib txawv tseem ceeb vim qhov sib txawv ntawm qhov tseem ceeb.
Post lub sij hawm: Aug-11-2025