CIS-TRANS ISOMERIZATION Rewritten from: Oliver Grummitt, THIS JOURNAL, 18, 447 (1941) hy F. B. Dutton Checkd CU: Vance Hnmiltou, East Lansing High School, Michigan
PREPARATION
Three 20 X 150-mm test tuhes; dimethylmaleate; a 57, w11;tiou of hromine in carbon tetrachloride; a 6CO-ml heaker and provision for heating it; a 75-100 w ~ tlight t bulh and suitable ext,ension cord. DEMONSTRATION
-
H-C-CO.OCHs
Bromine
H-C-COOCH1
Light,
I1
Dimethylmalrate
H-C-CO.OCHx CH,O.OC-4.H Dirnethylfumaratr
opaque coverinp. I'lace the three tuhes in a heaker of boiling water so that each receives the same amount of light from the 75-100 watt bulh which is plared one foot away. At the end of 5 minutes, remove the tubes and roo1 with shaking under the cold water tap. The irradiated sample containing the catalyst rapidly solidifies as colorless crystals of dimethylfumarat~e. The wrapped tube containing bromine appears nnchanged. The third tube which contained no ratalyst hot which was irradiated also appears unchan~ed. REMARKS
Into enrh of three test tuhes measure 10 ml portions of dimethylmaleate. Into two of the test tuhes place two drops of a 5% solution of bromine in carbon tetrachloride. Wrap one of these test tuhes with dark
A discussion of t.he chemistry involved, and the recovery of the dimethylfumarate are given in the referenre cited above. A synthesis of dimethylmaleate appears below.
Jolrrnol of Chemical Education
SYNTHESIS OF DIMETHYLMALEATE
( A di-
.
.
Morch 1961
.
Rewritlen from: Oliver Grummilt, THIS JOURNAL, 18, 447 (1941) by F. B. Dutton Checlwd b ~ Vance : Hamilton, East Lansing High Srhool, Mirhigan
and t,hen once more with water. I t is dried over Drierit,e -or anhydrous magnesium suIfate and distilled. Collect 58 g (0.5 rnol) of rnaleic anhydride, 160 g (200 ml, Yield, 50 g, 70% 5.0 n~ols)of methyl alcohol, and 4-5 ml of concentrated .: ' the fract'ion boiling a t 200'-207'. of t'he t'heoretical. sulfuric acid are refluxed on a steam bath for 4-5 . hours. The condenser is then set for distillation and the excess water and alcohol are distilled off. The residue is washed wit,h two 20-ml portions of water, See cis-trans isomerization item above two 20-ml portions of 5% sodium bicarbonate solution, PREPARATION
