Molecular weights of products

Reaction temperature Yield Molecular weight of product... 

Figure 7 shows the limiting maximum molecular weight of products from a reactor of fixed size varies directly with the frequency factor of the initiator at a fixed activation energy, while the limiting conversion varies inversely with the frequency factor. In addition, the length of the chain-transfer controlled zone is increased inversely with the frequency factor. 

Figure 2. Plot of molecular weights of products vs. irradiation time for the photolysis of 10 A, in benzene B, in the presence of methanol in benzene.

The route has the advantage that the anode does not need to be sacrificial, thus avoiding the generation of metal salts. However, the molecular weights of products obtained using this method are as yet very low, and mass spectral data for the oligomeric PMPS indicate a maximum DP of 5. 

Ma = molecular weight of reactant A Mb = molecular weight of product B... 

Imai, Saegusa, Furukawa et al. (48,66) carried out kinetic studies of THF polymerization in bulk and in cyclohexane solution at 0° C. They used a ternary catalyst system consisting of AlEt3-H20(2 l)-epichloro-hydrin (ECH). They obtained high molecular weight polymer and noticed no evidence for either termination or transfer. Their polymerizations were preceded by an induction period as shown in Fig. 13 but after that their data could be fitted to an equation of the same form as equation 42. This time [f0] was defined as the concentration of propagating species ([P ]) determined from the amount and the molecular weight of product polymer. 

The polydispersity increases with reaction time. At temperatures higher than 60 °C, the polydispersity and the molecular weight of products obtained by buradiene polymerization in dioxane16) strongly depend on temperature. The optimum characteristics (best yield, lowest polydispersity) are obtained between 50° and 60 °C. The polymerization of dienes, alkyl acrylates and styrene in the presence of 4,4 -azobis-(4-cyano-n-pentanol) has also been described 22 25). 

Cationic polymerisation (via initiation with sulfuric add or boron trifluoride) or anionic polymerization (in the presence of sodium ethoxide) were used for synthesis of polymers from 1,4-benzoquinone [124]. The number average molecular weight of products varied from 10 to 47 thousand, depending on the catalyst and its concentration. The polymerization product 101 contains hydroquinone and benzoqui-none moieties and has remarkable AO activity in stabilization of SBR at 100 °C. 

Starting from MPDA an overall yield for the process of around 90% is obtained, which means that the carbon efficiency (ratio of carbon in product to reactants) and overall atom efficiency (yield ratio of molecular weight of product to reactant) are 90% and 99%, respectively. The waste and any toxic by-products generated from the process are catalytically treated to give nitrogen, water and low quantities of carbon dioxide (about 200 kg per ton nicotinamide). 

In method SC, polymers often precipitate during the reaction. Molecular weights of products produced by this reaction are lower than those obtained by the other two methods (see Table VI). In some cases, pyridine is added to the solution (28). 

NMR analysis, respectively. Hence, the molecular weights of products formed in this and related published work are in good agreement. This is largely due to that, molecular weight of products are determined by their solubility in the reaction medium. In other words, when chains grow to a length at which they are poorly soluble, they precipitate from solution. 

P-Eliminations from alkyl complexes are the most common class of elimination reaction, and p-hydrogen elimination is the most common class of P-elimination process. P-Elimination reactions increase the coordination number of the complex therefore, they require an open coordination site at the metal center. These reactions do not change the oxidation state of the metal, This p-elimination chemistry occurs as part of many catalytic processes or as side reactions that limit yields or molecular weights of products formed by catalytic processes. 

Theoretical yield = (moles of limiting reagent)(ratio)(molecular weight of product)... 

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