issue while using datatable.select()

i need select some data from datatable as follows

dt.Select("RequestID=" + id).CopyToDataTable();//this is the actual selection statement it works fine
but when i try to pass RequestID as parameter its throwing an error.saying column name doesnt exist
here is the code which i tried

string distinct="RequestID";

tempTable = dt.Select("'"+distinct+"'='" + id).CopyToDataTable();

any pointers will be helpfull thanks in advance