Differentiation of ethanol and methanol

Principle

Borax (sodium tetraborate, Na2B4O7·10 H2O) hydrolyzes easily. The boric acid which is so formed reacts easily with methanol to form boric trimethyl ester, which is volatile and burns with a green flame. Boric triethylester is only produced in this way when
the reaction is proton catalyzed or if pure boric acid is used.

Advanced courses: This experiment can be regarded as a simple esterification reaction and can be discussed when esterifications or nucleophilic substitutions are discussed in general. The boric triester can be compared to the triesters of glycerol.

Learning objectives

• Methanol can be distinguished from ethanol by the formation of the methyl ester.
• This ester burns with a green flame, while ethanol burns with a pale-blue flame.

Benefits

• Easy teaching and efficient learning by using interactive experimentation PHYWE-Software
• Experiment is part of a complete solution set with experiments for the topic Organic Chemistry matched with international curriculum: all topics are covered