Unrecognizable lexical token when using 1/2 in IF statement

In IF statement, my string has a value 1/2, its giving me the following error

2(0).1(0).1(0).0(%g1).OBX(%s1).#3(0).[0]  eq =Prepared in 1/2 Units

IF expression parse failed: Unrecognizable lexical token

Error occurred at: ‘/2 Units

I have tried escaping the 1/2 with the following

1/2 but it does not work.

thanks in advance