Stereochemistry of Butenedioic Acid

Stereochemistry of Butenedioic Acid

Objective: To study the interconversion of two geometric isomers,

maleic acid (cis isomer) to fumaric acid (trans isomers), the

differences in physical properties between this pair of cis-trans

isomers and determine the stereochemistry of addition of bromine to

butenedioic acid.

Chemicals and Apparatus:

2 grams of maleic acid, 10 cm3 of concentrated hydrochloric acid, 10

cm3 of bromine water[1], one 50 cm3 beaker, one 100 cm3 beaker, one

250 cm3 beaker, one 10 cm3 measuring cylinder, one piece of spatula,

one piece of water glass, one glass rod, a few pieces of filter paper,

a set of Buchner funnel, a filter flask with side tube, three glass

capillary tubes, a set of melting point apparatus, one long hollow

glass tubing, one electronic balance, one heater and the oven

Background:

Stereochemistry is always encountered throughout organic chemistry.

And stereochemistry isomerism can be divided into two classes,

geometrical isomerism and optical isomerism. Although these categories

are not mutually exclusive, it is not uncommon to find compounds that

exhibit only one or the other of the two types. Most geometrical

isomers result from cyclic systems or restricted rotation about double

bonds. The preparation of fumaric acid by isomerization of maleic acid

and addition of molecular bromine to fumaric acid was illustrated in

the experiment.

Geometric isomers can be interconverted if the double bond is

temporarily converted to a single bond, about which rotation is