Why does this code sequenz give me an error 102

Why does this code sequenz give me an error 102

anybody an idea why this gives me an error 102, wrong syntax?
declare @i int=20
while @i<=50
begin
try
if convert(char,getdate(),@i) is not null
begin
select convert(char,getdate(),@i)
end
set @i=@i+1
end try
begin catch
set @i=@i+1
end catch;
end