Extent of intramolecular reaction

Results for thepolyurethane systems of Figure 6 and Table II are shown in Figure 9, where Mc/M is plotted versus pr,c the extent of intramolecular reaction at gelation(29). Here... 

Figure 9. Molar mass between elastically effective junction points (Mc) relative to that for the perfect network (Mc°) versus extent of intramolecular reaction at gelatin (pr,c) for polyurethane networks (29).

Figure 1, Ratio of molar mass between elastically effective junctions to front factor (M(-/A) relative to molar mass between junctions of the perfect network (M ) versus extent of intramolecular reaction at gelation (pj- (.) Polyurethane networks from hexamethylene diisocyanate (HDI) reacted with polyoxpropylene (POP) triols at 80°C in bulk and in nitrobenzene solution(5-7,12). Systems 1 and 2 HDI/POP triols >i= 33, V2= 61. Systems 3-6 ...

Figure 4. Extent of intramolecular reaction at complete reaction leading to inelastic loops (pj- g) versus p q.

Table II. Comparison of calculated and experimentally derived values of the final extents of intramolecular reaction for RA2 + RBf polymerisations, under conditions of the random reaction of functional groups (p° o)...

The results are shown in Figure 4, where Mc/Mc° is plotted versus Pp The molar mass between junction points of the perfect network(Mc°) is calculable from the molar mass and structure of the reactants (1, ) and was evaluated from the measured modulus using Equation 6 with A=l. pr Q is the extent of intramolecular reaction at gelation, given by the... 

Figure 8. Predicted correlations(24)betvi/een reduction in shear modulus at complete reactionTMc/Mc°) extent of intramolecular reaction at gelation(pi- q) for an RA3 polymerisation.

The limited extent of intramolecular rearrangements undergone by the chiral oxonium ions 35 and 36 at 720 torr and at 40 °C (Table 22) allows their use for probing the regio- and stereochemistry of the displacement reactions of Scheme 19. In this case, the allylic alcohol, precursor of the chiral oxonium ions 35 and 36, acts as the nucleophile NuH. The relevant results are condensed in Scheme 21. 

In the case of cyclopropyl-diazo-acetate 72 energy transfer reduces the extent of intramolecular in favour of the intermolecular reactions 146). 

Fig. 54. U3-lntramolecular hydrogen transfer catalysed by a single base. According to this proposal the extent of intramolecular transfer depends on the rate of the tautomerisation process versus the exchange process (reaction a plus b).

Most polyamides are prepared by a direct amidation reaction between diacids and diamines, and numerous combinations of monomers are possible. This reaction is accompanied by the elimination of water, and the amount of water released can serve as a measure of the extent of the reaction. In addition to this, the intramolecular reaction of the amino acids can also produce a polyamide (Fig. 3.2). 

Mesitylate esters are common intermediates in chemical synthesis and are very unstable. In order to monitor the extent of a reaction, it is often necessary to monitor all reaction species the precursor, mesylate intermediates, and end products. The mesylation reaction of 3-(2-isopropylphenyl)-l-hydroxy-1-R-propane (where R is a bulky chlorinated hydrocarbon) was followed on a diol column (A = 320 nm) using a 15-min 15/85 5/95 (75/25 hexane/toluene)/ethyl acetate gradient [883]. Intramolecular ring closure of the analyte occurred on the silica support at room temperature. Chromatography yielded a large, tailed cyclic ether peak followed by the mesylated material followed by the unieacted diol compound. Elution was complete in 14 min. The silica-facilitated reaction was greatly reduced when the system temperature was taken down to 10°C and was prevented when the system tenqterature was -30°C. 

As an extention of this reaction, the reagent promotes the intramolecular Pummerer-type rearrangement of ffl-carbamoyl... 

---