Abstract: Polyurethane forming compositions having a water insoluble, non-hydrocarbon diluent provide polyurethanes with improved properties. Polyurethane forming reaction mixtures having a water insoluble diluent provide compositions that permit the formation of polyurethanes in the presence of excess water. Polyurethane forming reaction mixtures having a water insoluble diluent provide compositions that permit the formation of water-blown, low-density polyurethanes in the presence of excess water. Polyurethane forming reaction mixtures having a water insoluble diluent provide compositions that permit the formation of water-blown, low-density polyurethanes. Polyurethane forming compositions having a water insoluble, non-hydrocarbon diluent provide polyurethane foams with improved dimensional stability properties. Polyurethane forming compositions having a water insoluble, non-hydrocarbon diluent provide polyurethane elastomers in the presence of water.