Reconnection

Then detach and reverse the condenser, and reconnect it to the flask through a knee-tube for direct distillation, as shown in Fig. 60, p. 101, or Fig. 23(0), p. 45. Distil the mixture, by direct heating over a gauze, until about 8 ml. of distillate have been collected. Acetic acid is volatile in steam and an aqueous solution of the acid, containing, however, some acetaldehyde, is thus obtained. With a very small portion of this solution, perform the tests for acetic acid given on p. 347. 

Electronic Connectors. The complexity and size of many electronic systems necessitate constmction from relatively small building blocks which ate then assembled with connectors. An electronic connector is a separable electrical connector used in telecommunications apparatus, computers, and in signal transmission and current transmission <5 A. Separable connectors ate favored over permanent or hard-wired connections because the former facilitate the manufacture of electronic systems also, connectors permit assemblies to be easily demounted and reconnected when inspection, replacement, or addition of new parts is called for. 

Squirrel-cage induc tion motors are inherently single-speed machines, but multispeed operation can be obtained by reconnecting the stator windings of motors designed for this purpose. 

Nitrosyl chloride (Matheson Gas Products) with a purity specified as > 97% was used. Occasionally, the needle valve of the nitrosyl chloride tank clogs. After closing the tank, the valve is disconnected and flushed with acetone until the acetone remains colorless. The needle valve is reconnected after being dried with compressed air. 

Disconnection and reconnection of piping to verify that it does not stress system. 

Close each end of hose until reconnected unless made safe by draining and purging. 

There was another similarity to the first incident. In this case the equipment also had been prepared for repair and then had to wait for a couple of days until the maintenance team was able to work on it. During this period, the air lines were reconnected, the lockout removed, and the isolation valve opened. 

A similar incident occurred on a solids drier. Before maintenance started, the end cover was removed, and the inlet line was disconnected. When maintenance was complete, the end cover was replaced, and at the same time the inlet pipe was reconnected. The final job was to cut off the guide pins on the cover with a cutting disc. The atmosphere outside (but not inside) the drier was tested, and no flammable gas was detected. While cutting was in progress, an explosion occurred in the drier. Some solvent had leaked into the inlet pipe and then drained into the drier [19]. 

The inlet line should not have been reconnected before the guide pins were cut off. 

An unusual case of inadvertent reconnection occurred when a contract electrician pulled a cable, and it came out of the junction box. He thought he had pulled it loose, so he replaced it, but it had been deliberately disconnected [41]. 

The tube bundle was being withdrawn from a horizontal shell and tube heat exchanger. It was pulled out a few inches and then became stuck. The mechanics decided that the cause was sludge, and to soften it they reconnected the steam supply to the shell. The tube bundle was blown out with some force, causing serious injuries [9]. 

Specialist disconnection , Specialist reconnection . . Specialist commissioning , Specialist transport . . 

An exception is Schedule 5, Public Gas Supply Code, which deals with meter installation, use of anti-fluctuators and valves, reconnection of gas supplies, escapes of gas, etc. 

A clutch acts like an on-demand spacer coupling. In the disengaged position there is space between the two shafts. When the clutch is engaged, the mechanism hlls the void to reconnect the shaft. 

Care should be taken to avoid short circuits for instance, an insulated specimen, being common with the ground point of some potentiostats, can become electrically reconnected to the autoclave if the latter is not separated from ground by using an isolation transformer. 

Strategy XII Reconnections Synthesis of 1,2- and 1,4-Difunctionalised Compounds by C=C Cleavage... 

Suggest a synthesis of keto-ester (16), by a reconnection strategy. 

First thoughts might be of a Friede1-Crafts disconnect ion using anhydride (2) which could be made from cyclohexene. An alternative is to reconnect (1) immediately to (3) and make this by standard Grignard methods. Both routes use the same disconnections. 

Chloroketone (11) is a 1,6-difunctlonallsed compound and could be made from keto acid (12) which reconnects to (13). 

Optically active diacid (16) was needed as a synthetic intermediate. Reconnection gives (17) with no obvious disconnections. The FGA strategy provides a solution as a carbonyl group next to the ring (18) allows a Diels-Alder disconnection. 

Disconnection of the acetals leads nowhere but a,P disconnection (21a) gives symmetrical (22). This is a 1,6-dicarbonyl compound and can be reconnected to (23). Removal of the acetals now reveals a Diels-Alder adduct (24). 

The reconnection strategy for (35) via olefin (36) was ignored in the book (p T 228) and is not very helpful because dehydration of the obvious intermediate (37) gives a mixture of olefins. 

Consider the superficially similar diketone (38), is wrong with the reconnection strategy here ... 

Dicarbonyl disconnection of symmetrical (38) again reveals a suitable 1,6-dicarbonyl starting material (39) but reconnection gives an impossibly strained alkene (40). 

Giventhe impossibility of reconnection, what next best disconnection for (39) can you find What is the difficulty with it ... 

The diketo-ester (1) has 1,4 1,5 and 1,6-dicarbonyl relationships. Both the 1,4 and 1,5 relationships can be disconnected at the branchpoint in the middle of the molecule, to give sensible intermediates such as (3) and (4), but difficult synthons (2) and (5). The 1,6 reconnection requires symmetrical Diels-Alder adduct (6). 

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