Super-combination 574 -cooling

Ethyl phenylethylmalonate. In a dry 500 ml. round-bottomed flask, fitted with a reflux condenser and guard tube, prepare a solution of sodium ethoxide from 7 0 g. of clean sodium and 150 ml. of super dry ethyl alcohol in the usual manner add 1 5 ml. of pure ethyl acetate (dried over anhydrous calcium sulphate) to the solution at 60° and maintain this temperature for 30 minutes. Meanwhile equip a 1 litre threenecked flask with a dropping funnel, a mercury-sealed mechanical stirrer and a double surface reflux condenser the apparatus must be perfectly dry and guard tubes should be inserted in the funnel and condenser respectively. Place a mixture of 74 g. of ethyl phenylmalonate and 60 g. of ethyl iodide in the flask. Heat the apparatus in a bath at 80° and add the sodium ethoxide solution, with stirring, at such a rate that a drop of the reaction mixture when mixed with a drop of phenolphthalein indieator is never more than faintly pink. The addition occupies 2-2 -5 hoius continue the stirring for a fiuther 1 hour at 80°. Allow the flask to cool, equip it for distillation under reduced pressure (water pump) and distil off the alcohol. Add 100 ml. of water to the residue in the flask and extract the ester with three 100 ml. portions of benzene. Dry the combined extracts with anhydrous magnesium sulphate, distil off the benzene at atmospheric pressure and the residue under diminished pressure. C ollect the ethyl phenylethylmalonate at 159-160°/8 mm. The yield is 72 g. 

T.T.S curves as those in Fig. 3.21 can be developed for material cooled very rapidly following solution treatment but the C curve range is a OO-550°C and the nose is at very short times. Freedom from sensitisation in welding can be obtained by ensuring extremely low carbon (and nitrogen) but such levels are not commercially feasible. Stabilisation by niobium and titarium is feasible, but higher ratios are needed than with austenitic steels. With most of the super ferritic group a combination of a practical low carbon level and titanium addition is used. 

The essential thermodynamic quantity for the liquid trihalides is the heat capacity, which in combination with the data for the solid phase gives the enthalpy/entropy of fusion. With these two quantities the Gibbs energy of the liquid phase can be calculated and extrapolated to the super-cooled state, if needed. 

Super cooling growth is a combination of equilibrium and step-cooling techniques. The temperature of the solution is decreased of AT below the Ta, brought into contact with the substrate and then the solution is cooled down at a rate a (K min-1). 

The super cooling growth is a combination of the equilibrium and stepcooling modes. Therefore, the solution (9.12) is given by a linear combination of (9.9) and (9.11) in a first approximation. 

To a solution of the crude imidate 36a obtained as above in p-xylene (50 mL) was added potassium carbonate (100 mg), and the reaction mixture was heated at reflux for 13 h. After cooling to room temperature, the mixture was filtered through a pad of Super-Cel, and the precipitate was washed with toluene. The combined filtrate was evaporated in vacuo, and the residue was purified by silica gel chromatography eluting with ether/hexane from 1 10 to 1 5 to give the title compound 37a (1.02 g, 91%). 

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