no, but there is a reference that says you must be able to show 8 hours of rest in the preceding 24 hours....thus, the 16 hour "duty" day is born

see
121.471c1
135.265c1
121.5031
121.505b


there are some exceptions for international (eg long range pacific type flying). But, the big consensus is that a 16 hour day is enough. And, if you look into the human factors issue, a 16 hour day is excessive and should be raising some major warning flags if you are working for that long