The Hydration Rate of Trimethyl Ethylene in Different Acids. The Nitration of Para-Cresol and of Para-Cresyl Carbonate in the Presence of Sulfuric Acid. The Preparation of Crystalline Lactic Acid

The hydration of trimethyl-ethylene is effected by different acids. At constant ionic strength the rate is first order with respect to both pentene concentration and the nitric acid concentration. The rate at a given acid concentration is increased on the addition of potassium nitrate. Other acids were used alone as follows: hydrochloric, perchloric, hydrobromic, dithionic, p-toluene-sulfuric, picric, sulfuric, oxalic and acetic. Strong acids give not much different rates. The dibasic acids like sulfuric and oxalic have mostly their first hydrogen ion effect on the rate of hydration. Dithionic acid shows its second hydrogen ion effect. Nitration of p-cresol and p-cresyl carbonate have been carried out in the presence of sulfuric acid. It was found in the case of p-cresol that the ortho directive power of the hydroxyl group decreased as sulfuric acid increased, and that more and more of the entering nitro group took up a position meta to the hydroxyl. In the case of p-cresyl carbonate, increase in the amount of sulfuric acid likewise increased the meta-ortho ratio. This change in directive power is ascribed to the salt-forming property of the oxygen atom of p-cresol and p-cresyl carbonate. Several methods have been worked out for obtaining optically active lactic acid (both isomers) from a commercial aqueous syrup. One of the methods consists of fractional distillation followed by fractional crystallization from a mixture of equal volumes of ethyl and isopropyl ethers. This process effects a good separation of the active isomer ℓ(+) from the dℓ- form. The active acids were also prepared by way of their zinc ammonium salts obtained by resolution of the commercial syrup. It was also found that when zinc ammonium d(-) lactate was mixed with a large quantity of the double salts of the dℓ acid, the active acid could be separated out by warming up to 55°. Some of the properties of the crystalline acids were described.