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For centuries, oil from the seeds of the chaulmoogra tree was used against Hansen's disease, also called leprosy, but it was hard to give in a form that worked. A 23-year-old chemist in Hawaii found a chemical fix. This post covers Alice Ball's work, the simple organic reaction at its heart, why her credit took decades, and what students can learn from her.
Who was Alice Ball?
The University of Hawaiʻi describes Ball (1892–1916) as its first African American graduate and the first woman to earn a master's degree in chemistry there, in 1915, at what was then the College of Hawaiʻi. She went on to become the school's first African American woman chemistry instructor.
Before Hawaii, she studied pharmaceutical chemistry at the University of Washington, as the Oxford University Museum of Natural History notes. While there she co-authored a 1914 paper in the *Journal of the American Chemical Society*, "Benzoylations in ether solution", with William Dehn.
What problem was she asked to solve?
The University of Hawaiʻi says that because of her master's research on kava, she was recruited by the US Public Health Service's Kalihi Hospital to apply the same technique to a treatment for Hansen's disease. Dr Harry Hollmann, the doctor at Kalihi Hospital, encouraged her to explore chaulmoogra oil.
What did she do?
She converted the fatty acids of chaulmoogra oil into their ethyl esters, which could be administered by injection. The UH 2026 report on the National Historic Chemical Landmark describes the American Chemical Society's citation as recognising her technique for preparing ethyl esters from the fatty acids of chaulmoogra oil so it could be given to patients by injection.
The method, later called the "Ball Method", became the first successful treatment for Hansen's disease. According to the University of Hawaiʻi, it was used on thousands of patients until sulfone drugs arrived in the mid-1940s. It allowed some patients at Kalaupapa, the isolation settlement on Molokaʻi, to return to their families.
Why was her credit delayed?
Ball died on 31 December 1916, aged 24, before she could publish. The University of Hawaiʻi says that Arthur Dean, then president of the College of Hawaiʻi, continued the work and published it without mentioning her key research, and the injectable became known as the "Dean Method". Dean and his colleague Richard Wrenshall published on fractionating chaulmoogra oil in 1920.
In 1922, Hollmann published "The fatty acids of chaulmoogra oil in the treatment of leprosy and other diseases", and, as the university puts it, attributed the process to her as the "Ball Method". Recognition grew slowly: the Board of Regents' Medal of Distinction in 2007, Alice Augusta Ball Day in Hawaiʻi, and in 2026 the ACS landmark designation.
Worked example: the ester chemistry
Esterification joins a carboxylic acid and an alcohol, releasing water:
R–COOH + C₂H₅OH ⇌ R–COOC₂H₅ + H₂O
A main fatty acid in chaulmoogra oil is chaulmoogric acid, C₁₈H₃₂O₂ (PubChem). Its ethyl ester is ethyl chaulmoograte, C₂₀H₃₆O₂ (PubChem).
Problem. (a) Check that mass is conserved in the reaction. (b) How much ethyl ester can 100 g of the acid give, at 100% yield? Use C = 12.011, H = 1.008, O = 15.999.
(a) Molar masses: acid = 18(12.011) + 32(1.008) + 2(15.999) = 280.45 g/mol; ethanol, C₂H₆O = 46.07 g/mol; ester = 20(12.011) + 36(1.008) + 2(15.999) = 308.51 g/mol; water = 18.02 g/mol.
Left side: 280.45 + 46.07 = 326.52 g. Right side: 308.51 + 18.02 = 326.53 g. Equal within rounding.
(b) Moles of acid = 100 ÷ 280.45 = 0.3566 mol. Ester = 0.3566 × 308.51 ≈ 110.0 g.
The ester has a higher molar mass than the acid because the –H of –COOH is replaced by –C₂H₅, a net gain of C₂H₄.
Common mistakes:
Writing water as coming from the alcohol's –OH alone. In acid-catalysed esterification, the –OH usually comes from the acid and the –H from the alcohol.
Forgetting the reaction is reversible. Removing water or using excess alcohol pushes it forward.
Naming the ester backwards. It is ethyl chaulmoograte: alcohol part first, acid part second.
How is leprosy treated today?
This is history, not medical advice. The World Health Organization says leprosy is caused by the bacterium *Mycobacterium leprae*, is curable with multidrug therapy (dapsone, rifampicin and clofazimine), and that WHO has been providing this treatment free of cost. It lists India among the countries still reporting more than 10,000 new cases a year. Anyone with symptoms should see a doctor.
What can a student learn from Alice Ball?
A transferable method is powerful. Techniques from her kava research carried over to a new problem.
Small chemistry, big effect. Turning an acid into an ester is a Class 12 reaction; applied to the right problem, it changed patients' lives.
Record and share your work. Her story shows what happens when results are not written down under your own name.
The exam side of this reaction is in our post on carboxylic acids and their derivatives. If a reaction mechanism does not make sense yet, the Fermi Concept Library has a lesson for each concept in chemistry and biology, so you can fill that gap first.
Practise now: find the molar mass of ethyl hydnocarpate, the ethyl ester of hydnocarpic acid, C₁₆H₂₈O₂ (answer: C₁₈H₃₂O₂, 280.45 g/mol).
