not exactly, but thymol is an active ingredient in Listerine

imageLast evening at the Cathedral of St. John the Baptist in Savannah, Georgia, Barrie Schwortz (pictured here as he appeared in 1978 with Secondo Pia’s camera from 1898) gave an outstanding talk  on the Shroud of Turin and the work of STURP.  See the TEDx Talk (link in the upper right hand corner) to get a much shorter example of one of Barrie’s presentations. Barrie went on for two hours. My wife and I were totally captivated every minute of those two hours. Barrie knows his stuff. Yes! But he is funny, as well, and we laughed the whole evening. (Thank you Barrie, for mentioning the blog and the discussions we are having about some of the subjects you discussed.)

Towards the end of his talk, Barrie was explaining why should be cautious about a new round of carbon dating at this time. There are some concerns that first need to be addressed. One was the possible effect of thymol on the shroud. Thymol was used to sterilize the shroud’s wood lined reliquary after cutting samples from the cloth. Ray Rogers, in his book, “A Chemist’s Perspective On The Shroud of Turin,” writes:

The custodians had allowed a small sample to be cut from the Shroud for textile analysis in 1973. Without consulting any of the scientists who had studied the cloth in 1978, the custodians allowed a much larger sample to be cut for radiocarbon dating in 1988. The date was reported as AD 1260-1390. At the time the cloth was sampled, the reliquary was treated with thymol, a phenolic compound used to sterilize materials. Thymol reacts with cellulose (linen), and the cloth’s composition has undoubtedly changed.

Rogers, many pages later, goes on to say:

. . . They sterilized the reliquary before the Shroud was replaced in it. They give the times during which bags of thymol were in the reliquary, but there is no way to estimate how much vapor reacted or was adsorbed on the walls of the container Thymol has a high vapor pressure. and it adsorbs strongly to any type of surface. The reliquary was lined with wood. Wood has a cellular structure and composition that favors absorption of materials like phenols. You can think of it as blotting paper for thymol.

Surface areas are routinely measured in science by adsorbing vapors on the materials and measuring amounts (usually called the BET method). A significant amount of thymol could have adsorbed on the wood, and wood has a large cellular surface area. More thymol would have reacted with the cellulose and more reactive hemicelluloses, lignin, and plant gums of the wood. No analyses were done. The amount of thymol left in the reliquary is unknown, but it is critical.

Some thymol would have desorbed and transferred onto the Shroud rather quickly. The desorption would reduce the free thymol concentration, reversing the equilibrium of thymol-wood reactions This would provide more thymol for reactions with the Shroud. Given enough time, reactants keep reacting until they reach their lowest energy state or equilibrium. I can not estimate the composition of the Shroud as it was taken from the reliquary. Apparently the persons involved with the 1988 sampling fiasco did not try.

Thymol is a “phenolic” compound, closely related to carbolic acid (phenol). The use of thymol shows a complete irresponsible ignorance of chemistry. Many superbly qualified chemists live in Europe and the United States, and some of them have had years of experience with the Shroud. They care about the Shroud. Many specialists on carbohydrates would have been happy to consult free of charge. Why were none asked about the long-term effects of thymol on cellulose (linen)? On iron compounds?

Thymol is also called “thyme camphor.” It is obtained by steam distillation of different species of plants of the genus Thymus or Ajowan. All of its carbon is modern carbon. Each modern thymol molecule that is grafted onto the linen will reduce the apparent age of the cloth by some amount. A significant amount of reaction will totally destroy the option for making accurate radiocarbon age determinations on the cloth. . . .

I have heard some say the Thymol effect might be only a few years. I’ve heard others say that we have no idea what the effect might be. Might be is the point.