Condensation during heating

The use of reflux condensers during the acetylation is not absolutely essential, since very little evaporation of the acetylating mixture from an open conical flask would occur during heating on the water-bath. The use of... 

Furfural was first isolated in the eady nineteenth century. Dobereiner is credited with the discovery. He obtained a small amount of a yellow "oil" (too Htde to characterize) as a by-product in the preparation of formic acid (8). Other chemists found that the same "oil" having a charactedstic aroma could be obtained by boiling finely divided vegetable materials such as oats, com, sawdust, bran, etc, with aqueous sulfuric acid or other acids (9,10). The oil was present in the Hquid resulting from condensation of the vapors produced during heating. The empirical formula was determined by Stenhouse... 

In the calcium refining process, the chromium reacts with calcium vapor at about 1000°C ia a titanium-lined bomb, which is first evacuated and then heated to the proper temperature. A pressure of about 2.7 Pa (20 p.m Hg) is maintained during heating until the calcium vapor reaches the cold end of the bomb and condenses. This allows the calcium vapor to pass up through the chromium metal where it reacts with the oxygen. Metal obtained by this process contains 0.027 wt % oxygen, 0.0018 wt % nitrogen, 0.008 wt % carbon, 0.012 wt % sulfur, and 0.015 wt % iron. 

All the steam is assumed to condense during the heating period, therefore the steam efficiency, E, equals 1. The standard state for enthalpy calculations is considered to be that of the pure liquid components at 0°C and 1 atm. 

Thiophenol.—Benzene sulphochloride (8 g.) is allowed to run in small portions from a dropping funnel into a round-bottomed flask containing 20 g. of finely granulated tin and 50 c.c. of concentrated hydrochloric acid. During the addition of the sulphochloride and until most of the tin has dissolved, the flask, which is fitted with a double neck attachment carrying a reflux condenser, is heated on the boiling water bath. The mercaptan produced is distilled with steam and extracted from the distillate with ether. The ethereal solution is dried over sodium sulphate, the ether is removed by distillation, and the thiophenol which forms the residue is likewise distilled. It passes over as an almost colourless liquid at 173°. 

---