Water boils at 212 degrees F (100C)...but that's what you meant I'm sure

. Anti-freeze does not raise the boiling point - the pressure of the cooling system does (that's why when you take the cap off a hot engine it boils over like a geyser). The coolant temp of the Cat runs from 200 thru 215 as normal, up to 230 before the big red light comes on. If you see that light you are already in trouble and about 7/8 on the gauge.
The purpose of antifreeze is to 1) prevent freezing, 2) prevent corrosion, 3) lubricate the pump seals.
So....no anti-freeze is not good (worst choice);
ALL anti-freeze is ALSO not good (diminished cooling over all water);
30 to 40% is best. If it gets colder than that you have the wrong car for your locale! (you can't start it that cold anyway with the rubber-band timing belt)
I refilled mine with 30% Dex-cool and 70% distilled water with a bottle of Red-Line Water Wetter added. I choose Dex-Cool as a preference, it is good stuff IF there is no leaks or contamination. The 30% mixture was intentional, anti-freeze (the green or the red stuff) is not as effective at heat transfer than pure water (.74 to 1.0). You need the corrosion protection and the lubrication, but unless your car is exposed to -20 for a duration its too much if you use more anti-freeze. And the Cat needs all the help it can get to cool without the fans kicking in. The Red-Line is compatible with the Dex-Cool and improves the heat transfer above the level of pure water, and it also has corrosion protection and lubrication. So far the results are really good.
I have another post (My Cat Lives Again) that details all I did to my cooling system.