The diolefins and alkenyl aromatics are very unstable components which can give gums by polymerization.In giving olefins and alky aromatics the hydrogenation improves the product quality.

二烯烃和烯基芳烃是非常不稳分，聚凝胶。对于给烯烃和烷基芳烃，氢化以改善品质量。