Rationality depends heavily on the categorical imperative. The categorical imperative is universally binding to all rational creatures to guide the good will and cause us to be moral. Without morals and the categorical imperative we cannot be rational.
The supreme determination
of a good will depends on whether the person commited the act based on their inclination or out of moral duty. If someone does something expecting a certain outcome or due to a concequence it is not a good will, but if someone does something based on the respect for a moral law, it is a good will.
Immanuel Kant is not a consequentialist. His philosophy focuses on the exact opposite of what consequentialism is built upon. Consequentialism focuses on the results of someone's actions being the basis for their conduct, whereas Kant focuses on moral duty being the basis for someone's conduct.