Amine equivalent, defined

Amine equivalent is defined as the weight of sample which will combine with 1 g equivalent weight of dibutylamine. 

It is assumed that Zi does not change in the course of the reaction, whereas Z2 increases. The conversions of amine and epoxy equivalents, defined as pA and pB, are related pA = fpB- Then... 

The 4,4 -MDA is sold commercially with a diamine assay of 98 —99%. The major impurity is the 2,4 -MDA isomer, which can be present in amounts up to 3%. PMDA products are normally defined by hydrogen equivalent weight and viscosity. Typical products exhibit a 50 hydrogen equivalent weight and a viscosity of 80 140 mPa-s(=cP) at 70°C. PMDA products normally contain, in addition to the isomers and oligomers of MDA, small amounts of aniline, water, chlorides, and various alkylated amines. AH MDA products should be stored in sealed containers in a cool dry area. 

Many physical and process constraints limit the cycle time, where cycle time was defined as the time to the maximum exotherm temperature. The obvious solution was to wind and heat the mold as fast and as hot as possible and to use the polymer formulation that cures most rapidly. Process constraints resulted in a maximum wind time of 3.8 minutes where wind time was defined as the time to wind the part plus the delay before the press. Process experiments revealed that inferior parts were produced if the part gelled before being pressed. Early gelation plus the 3.8 minute wind time constrained the maximum mold temperature. The last constraint was based upon reaction wave polymerization theory where part stress during the cure is minimized if the reaction waves are symmetric or in this case intersect in the center of the part (8). The epoxide to amine formulation was based upon satisfying physical properties constraints. This formulation was an molar equivalent amine to epoxide (A/E) ratio of 1.05. 

It was shown that complexes 19 of the zwitterionic precursors of ortho-quinone methides and a bis(sulfonium ylide) derived from 2,5-di hydroxyl 1,4 benzoquinone46 were even more stable than those with amine N-oxides. The bis(sulfonium ylide) complexes were formed in a strict 2 1 ratio (o-QM/ylide) and were unaltered at —78 °C for 10 h and stable at room temperature under inert conditions for as long as 15—30 min (Fig. 6.18).47 The o-QM precursor was produced from a-tocopherol (1), its truncated model compound (la), or a respective ortho-methylphenol in general by Ag20 oxidation in a solution containing 0.50-0.55 equivalents of bis(sulfonium ylide) at —78 °C. Although the species interacting with the ylide was actually the zwitterionic oxidation intermediate 3a and not the o-QM itself, the term stabilized o-QM was introduced for the complexes, since these reacted similar to the o-QMs themselves but in a well defined way without dimerization reactions. 

The simplest isolable species that fits this description is piperazine (27) with an enthalpy of formation44 of 29.4 kJ mol-1. Can we reliably estimate this value in terms of the conceptually simpler acyclic amines, acyclic polyamines, alicyclic amines or other heterocycles One may estimate it simply as the sum of the enthalpy of formation of cyclohexane (2, n = 6) and twice the exchange energy, S5. The predicted value is 21 kJmol-1, suggestive of at least 7 kJmol-1 of strain. Do not forget that 27 should enjoy stabilization as befits its being a vie-diamine. This destabilization is twice that of piperidine (3, n = 6) as relatedly defined by its measured enthalpy of formation and that estimated by summing the enthalpy of formation of cyclohexane and 1 -85. Equivalently, disproportionation reaction 30 is found to be thermoneutral. 

For historical reasons, examples of case 2d, containing multiple amine or amide groups in their branches, will be discussed first. These types of dendrimers give rise to metal complexes of variable stoichiometry and unknown structures since they contain several more or less equivalent ligand units and not well-defined coordination sites. 

In an effort to exert more control over the spatial arrangement of the various sensitizer and acceptor groups, Meyer s group have turned to solid-state peptide (Merrifield) synthesis. The amino acid selected was proline, which has a secondary amine and a cyclic structure, forcing polyprolines to adopt a rigid, helical conformation. This means that the distance between substituents on the chain is much more well defined than in polystyrene. As described for the polystyrene-based systems, it is possible to set up a Donor-Ru-Acceptor assembly on a polyproline backbone that is capable of storing redox equivalents (Fig. 7.4). The distance dependence of back electron transfer between Ru-bpy and the oxidized donor (PTZ +) was measured and shown to occur via through-space interactions [23]. 

Poly(propylene imine) (PPI or POPAM) dendrimers are the first dendritic stmctures found in literature. They were first reported by Buhleier etal, who presented a divergent synthesis of branched and dendritic-like molecules. These simple structures were accomplished using controlled organic chemistry. In this case, a Michael reaction between a primary amine and two equivalents of acrylonitrile resulted in a dinitrile. Further reduction through Co(II)-catalyzed hydrogenolysis led to a terminal diamine (Figure 16). An iterative protocol allowed the con-stmction of what today is defined as a second-generation... 

The isocyanate equivalent is defined as the weight of sample which will combine with 1 g equivalent weight of phenyl isocyanate. The sample is generally a polyol, amine or other compound that possesses groups capable of reacting with an isocyanate. 

The neutral salicylaldimine nickel complexes described hy Grubbs and coworkers (195,196) show unprecedented fimctional group tolerance and are capable of incorporating substituted norbornenes, carbon monoxide, and a-co fimctional olefins into polyolefins with well-defined compositional distributions (eq. 7) (196). Furthermore, ethylene can be homopoljnnerized with these catalysts in the presence of various functional additives including acetone, water, ethyl alcohol, and triethyl amine. In the presence of 1500 equivalents of H2O, polyethylene was produced at a rate of 5.4 x 10 g PE/mol Ni/h. 

As was shown earlier, sulfonylureas are derived from a sulfonamide, a phosgene equivalent in some form, and a heterocyclic amine. Of these amines, the simple disubstituted pyrimidines and symmetrical triazines generally afford the most active herbicides. The following discussion will highlight tiie synthesis of a variety of different heterocyclic amines that have been incorporate into sulfonylureas to define the limits of herbicidal activity, and to (tiscover active herbicides with high crop selectivity. 

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