I have a need for smallest rectifier for 24 V 100 ma . I was thinking to use bav99s .I don't mind for 1.2 V vf . Is there a problem since it is not characterized as rectifier but rather as switching diode .
It is a tiny little surface mounted dual diode. It will be fine if you use two to make a bridge since its voltage and current ratings are higher than you need.
The diode is called a "switching" diode since it can switch on and off very fast. But it can also be used as a low frequency bridge rectifier.
But an ordinary 1N400x rectifier diode does not switch fast and cannot be used in high frequency switching circuits.
Is there a BAV99s which is a quad diode? No, the quad diode is a BAV99S.
The BAV99 from Philips/NXP and other manufacturers is a dual diode in a 3-pins surface-mount package. BAV99s are more than one of them.
The OP asked about using (two?) BAV99s as a full wave bridge rectifier.