Continuous insertion mechanism

As shown by calculations, the carbenoid mechanism of dichlorogermylene insertion in ordinary C—Cl bond begins by electrophilic attack of the vacant p-orbital of the Ge atom on the electrons of the bond . The vacant p-orbital does not interact with the unpaired electrons of the chlorine atoms. When the distance between the reactants decreases and becomes close to the value of the C—Cl bond length, inactivated transfer of Cl to the germylene center occurs with formation of a radical pair, followed by its recombination. The closer the components of the radical pair, the smaller the probability of radicals movement away from one another. The theoretical interest concerning the details of the germylene insertion mechanism is continuing. Thus, a quantum-chemical examination of... 

The polymerization undergoes a coordination-insertion mechanism. The initiation step involves nucleophilic attack of the active group, such as a hydride, alkyl, amide or alkox-ide group, on the carbonyl carbon atom of a lactide or lactone to form a new lanthanide alkoxide species via acyl-oxygen cleavage. The continued monomer coordination and insertion into the active metal-alkoxo bond formed completes the propagation step as shown in Figure 8.50. 

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. 

A machine with approximately 1000 needles continuously produces a fabric 5-m wide. The assembly process is more complex, slower, and more expensive than tufting. The pile yam and stitch yam are inserted into the knitting needle, and the stuffer yam is interlocked with the others through a separate feed mechanism of the machine. As with tufting, the loops of the pile fabric formed are sHt, creating the desired individual blades. 

Two types of continuous flow solid oxide cell reactors are typically used in electrochemical promotion experiments. The single chamber reactor depicted in Fig. B.l is made of a quartz tube closed at one end. The open end of the tube is mounted on a stainless steel cap, which has provisions for the introduction of reactants and removal of products as well as for the insertion of a thermocouple and connecting wires to the electrodes of the cell. A solid electrolyte disk, with three porous electrodes deposited on it, is appropriately clamped inside the reactor. Au wires are normally used to connect the catalyst-working electrode as well as the two Au auxiliary electrodes with the external circuit. These wires are mechanically pressed onto the corresponding electrodes, using an appropriate ceramic holder. A thermocouple, inserted in a closed-end quartz tube is used to measure the temperature of the solid electrolyte pellet. 

Weigh and finely powder not less than 20 methimazole tablets. Weigh accurately a portion of the powder equivalent to about 120 mg of methimazole and place in 100 ml volumetric flask. Add about 80 ml of water, insert the stopper and shake by mechanical means or occasionally by hand during 30 minutes, dilute with water to volume and mix. Filter and transfer 50.0 ml of the filtrate to a 125 ml conical flask. Add from a burett3.5 ml of 0.1N NaOH, mix, and add with agitation about 7 ml of 0.1N AgN03. Add 1 ml of bromothymol blue T.S. and continue the titration with 0.1N NaOH until a permanent, blue green color is produced. Each ml of 0.1N NaOH is equivalent to 11.42 mg of C,H,N S. 

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