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Every introductory thermodynamics text [15] [16] presents the fact that on such a plane the area under any curve is the heat transfer to the substance per mole, positive going from left to right and negative from right to left; moreover, in a cyclic process the net heat transfer to the substance is the area enclosed by the cycle's closed curve.
Cyclic acetals are very much more stable against acid hydrolysis than acyclic acetals. Consequently acyclic acetals are used practically only when a very mild cleavage is required or when two different protected carbonyl groups must be differentiated in their liberation.
A PV diagram plots the change in pressure P with respect to volume V for some process or processes. Typically in thermodynamics, the set of processes forms a cycle, so that upon completion of the cycle there has been no net change in state of the system; i.e. the device returns to the starting pressure and volume.
In organic chemistry, an acetonide is the functional group composed of the cyclic ketal of a diol with acetone. The more systematic name for this structure is an isopropylidene ketal. Acetonide is a common protecting group for 1,2- and 1,3-diols. [1] The protecting group can be removed by hydrolysis of the ketal using dilute aqueous acid.
The ratio of cyclic to acyclic acetals varies with reaction time since acyclic acetals are kinetically favored and cyclic acetals are the thermodynamically favored. [5] This unique formation of cyclic and acyclic acetals leads to varying degradation time because the two acetal groups hydrolyze at different rates. Acetalated dextran's ...
The cyclic changes described above produce serrations in the plastic region of the stress strain diagram of a tensile test that is undergoing the Portevin-Le Chatelier effect. The variation in stress also causes non-homogeneous deformation to occur throughout the sample which can be visible to the naked eye through observation of a rough finish ...
When their combined volume reaches the level of the side-arm, the upper, less-dense layer will begin to flow back to the reactor while the water layer will remain in the trap. The trap will eventually reach capacity when the level of the water in it reaches the level of the side-arm. At this point, the trap must be drained into the receiving flask.
Polyoxymethylene (POM), also known as acetal, [4] polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability.