This invention relates to novel hetero group containing perfluoroalkyl terminated neopentyl mercapto-alcohols which possess improved thermal stability.  They are useful in the preparation of low surface energy oil and water repellent coatings for textiles, glass, paper, leather, and other materials. 
One other bis-perfluoroalkyl terminated mercaptan has been previously described in U.S. Pat.  Nos.  3,758,447 and 3,886,201 and Japanese Sho 63-223,639.  However, this compound is a perfluoroalkyl ester of mercaptosuccinic acid and is not only expensive to prepare, but also is not thermally and hydrolytically stable.  Therefore, it is an impractical intermediate from which to obtain useful products. 
The instant twin-R.sub.f tailed mercapto-alcohols are readily isolated in high yield and purity.  In addition, because of the neopentyl skeleton is incorporated into all of the novel mercapto-alcohols, they are thermally stable as well. 
Bis-perfluoroalkyl mercapto-alcohols and derivatives thereof are useful because they possess a low free surface energy which provides oil and water repellency to a wide variety of substrates.  Mercaptans containing a single R.sub.f -function are known, but do not provide these properties to the same extent.  The proximity of the two perfluoroalkyl chains to one another greatly increases the attraction between these groups through Van Der Waal's interactive forces, and as a result the oil and water repellency of the twin-tailed mercaptans is much greater than the repellency inherent in single-tailed mercaptans.