Chapter 3, Problem 3CT

In 1976, a team of chemists in the United Kingdom was developing new insecticides by modifying sugars with chlorine (Cl₂), phosgene (Cl₂CO), and other toxic gases. One young member of the team misunderstood his verbal instructions to “test” a new molecule. He thought he had been told to “taste” it. Luckily for him, the molecule was not toxic, but it was very sweet. It became the food additive sucralose.

Sucralose has three chlorine atoms substituted for three hydroxyl groups of sucrose (table sugar):

The altered sugar binds so strongly to the sweet-taste receptors on the tongue that the human brain perceives it as 600 times sweeter than sucrose. Sucralose was originally marketed as an artificial sweetener called Splenda^®, but it is now available under several other brand names.

Researchers investigated whether the body recognizes sucralose as a carbohydrate by feeding sucralose labeled with ¹⁴C to volunteers. Analysis of the radioactive molecules in the volunteers’ urine and feces showed that 92.8 percent of the sucralose passed through the body without being altered.

Some people are worried that the chlorine atoms impart toxicity to sucralose. How would you respond to that concern?