Robert Donatti is head of the chemistry department at Hastings Research Institute and a dyed-in-the-wool misogynist and plagiarist. Although he’s also supposed to be doing chemical research, it seems like Donatti’s primary function is to obstruct Elizabeth's scientific pursuits. He hates that she is talented and resents the fact that a wealthy donor to the institute keeps donating money for the research that only she is capable of. In his mind, there’s a clearly defined hierarchy in life, where women should focus on family affairs and menial tasks and leave the independent research to men. This attitude is paradoxical, however, as Elizabeth’s work is certainly good enough for him to want to steal it. He plagiarizes Elizabeth’s work and tacitly encourages others to do the same. Donatti is terrified of being overshadowed by a more talented mind, particularly one belonging to a woman like Elizabeth Zott. The fact that he finds her attractive—as does everybody else at Hastings—only fuels his hatred of her.
Donatti also envies Calvin's scientific achievements but is constantly worried that Calvin is not producing enough material to make him worth the cost to keep him at Hastings. This dynamic exposes Donatti's lack of intellectual depth. He relies on the success of others, like Calvin, to bolster his own reputation. When other people don’t meet his expectations, he’s furious. Throughout Lessons in Chemistry, Donatti represents a mercifully dwindling trope of male character, one that clings obstinately to outdated ideas about gender roles and women’s capabilities. His constant resistance to Elizabeth's work and his casual willingness to demean his subordinates are a microcosm of the challenges women faced in the workplace in the 1960s.