~-PROPIOLACTONE REACTIONS WITH SALTSOF CARBOXYLIC ACIDS
March, 1948
1003
[CONTRIBUTION FROM THE B. F.GOODRICH RESEARCH CENTER]
8-Propiolactone, I V 1 p 2
Reactions with Salts of Carboxylic Acids
BY T.L. GRESHAM, J. E. JANSEN
Salts of 8-acetoxypropionic acid I1 and polyester acids (111) are formed in the reaction of & propiolactone (I) with aqueous sodium acetate. The strong tendency for the reaction of I with the primary products is minimized by increasing the mole excess of sodium acetate. CHaCHz
I I 4- CH&OONa + CH:COOCH&H&!OONa 0-bo I
(X
- 1) CHaCH, 1 1 O-C=C)
I1
4- CHoCOOCHnCHtCOONa ----+ CH,COO(CHsCH,COO).Na
I11
8-Acetoxypropionic acid (IV) is completely pyrolyzed to acetic acid and acrylic acid by distillation a t atmospheric pressure. CHaCOOCHzCHzCOOH + IV CHaCOOH
+ CHFCHCOOH
Attempts to prepare esters of I V by direct esterification result in alcoholysis and esterification to hydracrylates and acetates. The poly-ester acids V are colorless oils and they differ from polymers obtained from I by heat orlwith catalystss only in the end acetoxy group. Alcoholysis with methanol, using acid catalysis, results in a mixture of methyl acetate and methyl hydracrylate in amounts as expected from the average molecular weight, assuming one acetoxy group per molecule. CH&!OO(CHICH*COO).H
V CHsCOOCHa
+ CHsOH +
+ zHOCHZCH&!OOCH, + HI0
With several moles of I and one mole of sodium acetate the products are exclusively salts of polyester acids (111). Low temperatures are required to avoid hydrolysis of 1. Since the yield of polymer is higher than that expected from the molecular weight if each polymer molecule contains an acetoxy group, some polyhydracrylic acid is present due to hydrolysis of the polymers or polymerization of I. Products similar to those with sodium acetate are formed with salts of other carboxylic acids. The poly-ester acids from sodium caprate (VI) and disodium phthalate (VII) were viscous oils. CHa(CHJ&OO(CH&H&OO)t.rH
VI CsH,[ (COO(CHA!HzCOO)*.sH]z VI I (1) Gregory, Gresham, Jansen and Shaver, THISJOURNAL, TO, 999 (1948).
(2) Gresham, Jansen and Shaver, ib
