Dibutyl Squarate

Dibutyl squarate is an organic chemical compound, derivative of squaric acid. It is a diesther and a cyclic ketone. This substance is also known under the synonymic terms squaric acid dibutyl ester (SADBE), 3,4-dibutoxycyclobut-3-ene-1,2-dione or 3,4-Dibutoxy-3-cyclobutene-1,2-dione.


The physical state of dibutyl squarate is liquid clear to yellow color insoluble in water. Its boiling point is 1390C at 0.5 mm Hg. The substance is stable under normal conditions and incompatible with strong oxidizing agents.

Preparation and Application

Dibutyl squarate is immunological adjuvant. That means it can augment, activate, potentiate, stimulate, or modulate the immune response at the humoral or cellular level. In medicine, squaric acid dibutyl ester is widely applied as the cure for common warts. Such kind of treatment is popular due to its easiness and non-toxicity.

Besides, SADBA is considered as one of the best methods for hair loss treatment. It is often prescribed to combat alopecia totalis/universalis and alopecia areata. In this case, topical immunotherapy is used.

In chemistry, squaric acid dibutyl ester as well as the other derivatives of squaric acid takes part in synthesis of squarylium dyes, pharmaceutical intermediates, and photoconducting squaraines.

Storage and Safety

As the substance activates the immune system of human body, it may also cause the allergic reactions similar to those the poison oak causes. In some rare cases may occur blistering or lightening of the skin.

While working with dibutyl squarate you should remember several rules:

  • The compound may cause skin irritation, therefore it is strongly recommended to wear protective gloves while working with the substance and thoroughly wash your hands and face after.
  • Squaric acid dibutyl ester causes serious eyes irritation. Do not forget to put on an eye protection before handling.
  • After ingress in eyes, remove contact lenses if any and rinse with water for a few minutes. If the irritation persists, get medical help.
  • Avoid inhalation of vapors, mist or spray, as it may cause the irritation of the respiratory tract.

Dibutyl squarate should be stored well-closed light-resistant containers.