Dr. Glaser's "Chemistry is in the News"
To Accompany Bruice, Organic Chemistry, 3/e.
Chapter 6. Electron Delocalization and Resonance.

Editorial Comments

Benzene is a highly toxic material. Benzene can be deadly when you are exposed to 20,000 ppm for as short a period as 5 - 10 minutes. Benzene used to be a frequently employed solvent in chemical research and in industry for many decades. Yet, the use of large quantities of benzene is now prohibited in many instances and benzene is in fact avoided by chemists whenever possible.

So why would anybody want to expose himself or herself to benzene voluntarily? Or perhaps the better question would be: Why would anybody want to expose somebody else to benzene? Nail polish is a frequently used cosmetics item and to remove it you need nail polish remover. The best nail polish is the one that sticks the best and does not come of easily. Thus, to get rid of the best nail polish you need a really good nail polish remover. Not just any solvent will do, it's got to be a really good solvent - such as benzene. "Benzene is toxic? Well then let's just keep that quiet." that seems to be the motto of the industry. But that seems to be only part of the problem. People also seem not to want to hear the message.

While the toxic effects of cosmetics fully manifest themselves primarily in the people who are exposed to the chemicals in large quantities, there is a real risk even for the casual user. Perhaps it is time for better regulation of the cosmetics industry. What do you think about this issue?

Questions

Question 1: What are structures of benzene and tolune? What are the approximate melting and boiling points of benzene and tolune?

Answer 1: Use the ChemFinder.

Question 2: What were the symptoms suffered by manicurist Denise Santamaria which are thought to be due to benzene poisoning?

Answer 2: Digestive problems, frequent sinus infections and excruciating pain in back, chest and arms.

Question 3: The FDA is more interested in what goes "in" you than what goes "on" you. Is this attitude warranted when it comes to benzene?

Answer 3: No, not at all. According to Dr. Hampton, there is some indication that some chemicals are absorbed in great amounts through the skin. For example, "nitrosamines are absorbed through the skin in far greater amounts than when nitrite-preserved foods (such as bacon) are eaten." (It is therefore particularly worrysome that some sun screen lotions are contaminated by nitrosamines.) Benzene also is easily absorbed through the skin.

Question 4: Why do you think benzene is highly toxic to humans? [Hint: Think about the chemical and physical properties of benzene.]

Answer 4: Benzene is an excellent solvent for lipophilic (opposite to hydrophilic) materials. Benzene "dissolves" fats and lipids in your cells.

Chemistry & Society.
Question 5: The article contains the statement "There is vigorous industry and political pressure to keep using them," says Dr. Joni Loughran of the Paul Penders Company of Petaluma, Calif. "It is claimed that the risk is small and change takes time." How do you feel about that? Would you prefer more government involvement and regulation to protect consumer safety?