pdt@mhuxv.UUCP (tyma) (02/08/84)
Just a few facts to help confuse the discussion on catalytic converters: >I think catalytic converters produce both sulfuric and >sulfurous oxides. By far, more sulfur oxides are produced by the *combustion* process within the engine. The catalytic converter affects the distribution of the sulfur species--some sulfur (IV) oxides are converted to sulfur (VI) oxides, and some highly reduced sulfur forms (like hydrogen sulfide, the rotten-egg odor) are oxidized. The role of catalysis is to lower the energy barrier to a chemical reaction, allowing it to proceed faster at a lower temperature. The catalyst does this for the carbon monoxide oxidation (good), but it also does it for the sulfur and nitrogen compounds. Interestingly, the (unconverted) hydrogen sulfide gas is far more toxic than the sulfur-oxide gases. >Both of these combine with water in the atmosphere to produce >strong acids (strong enough to change the pH of rain and lake >water... ALL acids change the pH of water; that's what makes them acids. The acid formed by dissolving sulfur dioxide in water, sulfurous acid, is a weak acid; that formed from sulfur trioxide, sulfuric acid, is a strong one. >I don't know the exact way the sulfur in gasoline gets changed >into sulfur oxides... Burning. >Catalytic converters work by bonding oxygen to things (oxidizing). Not really--see above. Catalysis is also possible for the opposite of oxidation (reduction).