This news item was created by students Trent Welsh, Jared Johnson and Jarrod Staggs as part of their Chemistry 212 Collaborative Group Activities in WS00 under the guidance of Prof. Rainer Glaser.

Glaser's "Chemistry is in the News"
To Accompany Wade Organic Chemistry 4/e.
Chapter 21. Carboxylic Acid Derivatives.


For each of the following questions, please refer to the following article:

CYANIDE SPILL POURS ACROSS BORDER INTO YUGOSLAVIA
by Lisa Gurevitch (The Associated Press and CNN.com World News, 2000)


Editorial Comments

The widespread use of chemicals in industry brings an inherent risk of danger to life on Earth, and on January 30, 2000, cyanide demonstrated just this sort of threat. A dam leak at the Baia Mare gold mine company unleashed cyanide poison into the waterways of Europe, and an ecological disaster that some are comparing to Chernobyl ensued.




The spill originated in Romania, and within days the impact hit Hungary and Yugoslavia, polluting major rivers including the Danube and Tisa. Human drinking water remained safe because contaminant levels were not affected in local supply wells. However, the contamination proved deadly for river wildlife, and posed serious damage to the regional fishing industry. The misfortune came at a most inopportune time for this European region, which was already ecologically sore from the pollution aftermath of last year's NATO bombing.

A major issue raised by this disaster is how the European Union should now respond to it. Gold mining using cyanide leaching has caused disasters in other parts of the world, and the dangers of its practice are becoming obvious. It is generally agreed that protective measures should be taken, but the extent to which the government should be involved is a difficult question. We can let business be and accept that accidents happen. Check out the mining company's response to this spill on CNN World News. Or, believing that these companies do not always act for the public good, we can slap as many regulations as possible onto companies which deal with dangerous chemicals.

The business end of cyanide is the cyano group. This group consists simply of a carbon atom triple-bonded to a nitrogen atom. It is classified as a carboxylic acid derivative even though there is no carbonyl group present. This is because amides are easily made from cyano groups by the addition of water. Similarly, an amide can be easily converted to a cyanide by dehydration using a reagent such as POCl3.

Cyanide is a powerful poison especially when present as the anion in various chemical salts; sodium cyanide and potassium cyanide are the two most commonly found in the environment as industrial products. Upon contact with water, however, cyanide compounds form hydrocyanic acid, an even more toxic substance. Death can occur after ingestion of only small amounts of cyanide. All forms of cyanide adversely affect the brain, lungs, and heart. Cyanide gas is even the preferred method of capital punishment in gas chambers. Check out the Environmental Health Center on-line for exposure details.

Pertinent Text References
Chapter 21. Carboxylic Acid Derivatives.
See in particular the discussion of nitriles in Wade 4/e, p. 951.
Chapter 18. Section 18-15 on "Formation of Cyanohydrins."

Questions

Question 1: Why are cyano groups considered to be carboxylic acid derivatives?

Question 2: Hydrocyanic acid is extremely toxic. To get a feel for how it reacts, describe how hydrocyanic acid would react if it encountered an aldehyde or a ketone.

Question 3: How could cyanide-laced water be converted to acidic water?

Question 4: Considering the ecological effects of the spill, what are now the main economic concerns for towns and cities along the Tisa River?

Question 5: What, if any, governmental actions should the European Union take to curb the dangers of cyanide leach mining?


Suggested Answers

Question 1: Because cyano groups and amides are easily interchangeable by hydration/dehydration reactions.

Question 2: Hydrocyanic acid reacts with aldehydes and ketones to form cyanohydrines.

Question 3: Hydrate cyanide to form an amide, then hydrate again with acid catalysis to form the carboxylic acid.

Question 4: Fishermen have lost most of their fish for at least a year or two, and tourists are now afraid of the river. This creates a twofold hit on the economies of towns along the river.

Question 5: This is an open-ended question.