Glacial acetic acid (CH₃COOH) yog hu ua "glacial" vim nws solidifies rau hauv dej khov -zoo li crystals ntawm 16.6 degree, tsim cov khoom translucent uas zoo li cov dej khov es tsis tshuav cov kua qaub li qub.
Lub sij hawm "glacial" tuaj ncaj qha los ntawm nws lub cev tus cwj pwm ntawm qhov kub thiab txias: ntshiab acetic acid muaj qhov melting / khov ntawm 16.6℃(62℃F), txhais tau hais tias txawm tias me ntsis txias hauv qab chav sov (20-25 degree) tuaj yeem ua rau crystallization. Nyob rau hauv lub xeev no, CH₃COOH molecules tsim muaj zog hydrogen-bonded cyclic dimers, uas stabilize ib tug siv lead ua lattice zoo li cov dej khov. Piv nrog rau cov dej (melting ntawm 0 degree), acetic acid hloov ntawm qhov kub siab dua vim muaj kev sib koom ua ke muaj zog hauv nws daim ntawv ntshiab.
Lub npe "glacial" kuj yog siv los ua kom paub qhov txawv ntawm cov kua qaub dawb huv los ntawm cov tshuaj diluted xws li vinegar, uas feem ntau muaj 4% -8% CH₃COOH. Tsis zoo li cov kua txiv hmab txiv ntoo, uas tseem ua kua ntawm txhua qhov kub thiab txias, glacial acetic acid yog li 99% -99.8% ntshiab thiab tuaj yeem crystallize yooj yim thaum txias. Qhov sib txawv ntawm qhov sib txawv ntawm qhov concentration (≈99% vs. ≈5%) ncaj qha piav qhia tias vim li cas tsuas yog daim ntawv dawb huv nthuav tawm cov dej khov nab kuab-xws li kev coj tus cwj pwm solidification.
Hauv kev lag luam chemistry, glacial acetic acid muaj nuj nqis rau nws qhov tsis muaj dej (<1% water content), which improves reaction control in processes such as esterification and acetate production. Its solidification point at 16.6°C also affects storage and handling, requiring controlled temperature conditions above ~18–20°C to prevent crystallization in pipelines, drums, and reactors.
Vim li cas thiaj hu ua Glacial Acetic Acid?
Lub npe "glacial" yog li ntawd tsis yog hais txog cov dej khov ntuj, tab sis mus rau theem ntsuas tau - hloov khoom: siab - purity organic acid uas coj zoo li dej khov ntawm qhov kub me me vim muaj zog molecular hydrogen bonding thiab ze - tsis muaj dej.
