A solid phase organic synthesis method has been developed for the preparation of substituted methylene malonamic acids and malonic ester mono acids 5. Two substituents are introduced into the core molecule 5 by preparation of unsymmetrical malonic acid derivatives 2, followed by Knoevenagel condensation with aromatic or aliphatic aldehydes, giving resin-bound 4. Evaluation of the scope of these reactions led to the preparation of a 96-member library from a set of eight amines/alcohols (seven amines and one alcohol) and 11 aldehydes leading to 88 substituted methylene malonamic/malonate mono acids 5 and eight unsymmetrical malonamic/malonate mono acids 3. Structural validation and quantitation for every member of the library was obtained by evaluation of 1H NMR and HPLC, respectively. The 1H NMR data were obtained using automated delivery of DMSO solutions of every library member from a 96-deep well microtiter plate to a flow probe-equipped NMR spectrometer. HPLC data were used for determination of the extent of conversion of malonamic/malonate esters 2 to the products 5 by an external standard method. Summary information from the 1H NMR and HPLC data is viewed as plate diagrams for analysis of the final library.

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Solid-state 13C and 15N NMR spectroscopy was used to study the structure and thermochemistry of nylon-6,6. Experiments were performed on samples of nylon-6,6 heated in the presence of labeled adipic acid and hexamethylenediamine (HMD) monomers as well as labeled bis(hexamethylenetriamine) (BHMT), a molecule previously implicated as a potential nylon cross-linker. The uptake and subsequent reaction of labeled materials were characterized by a variety of solid-state NMR techniques. Reaction of the central (α) nitrogen of BHMT to form an amide occurs very rapidly. With time, transamidation causes this position to become indistinguishable from the bulk amide nitrogen in nylon. Rotational-echo double resonance (REDOR), a solid-state NMR experiment that permits the quantitative measurement of 13C−15N labeled chemical bonds, was used to detect the formation and breaking of carbon−nitrogen bonds due to polymerization and transamidation. The reaction of adipic acid and hexamethylenediamine (HMD) and the transamidation reaction between the resulting oligomers and bulk nylon were studied by heating nylon-6,6 in the presence of [13C]adipic acid and [15N]HMD and characterizing the resulting polymers with REDOR. The combination of stable isotope labeling and NMR spectroscopy illustrated in this work should be applicable to the study of a wide variety of polymers.

Differential thermal analysis has been used to reexamine the stable and metastable solid phases of cyclooctanone and the phase transitions. N M R and dielectric measurements were used to characterize the extent of molecular motions in each phase. Rotor phase I can be supercooled into a glassy crystal, I,. A single orientationally ordered phase, 11, is stable at low temperatures. Another phase, 11', is always metastable with respect to phase 11. The activation energies of self-diffusion and molecular reorientation in I are reported.

The Solid Phases of Cyclooctanone Studied by Thermal, NMR, and Dielectric Techniques -(reexamination of the stable and metastable phases and the phase transitions). -(ADAMS, J. M.; SNYDERMAN, D. M.; CONRADI, M. S.; J.

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INTRODUCTIONMagnetic resonance nondestructive evaluation (NDE) methods are being used successfully in the medical, biological and petroleum industries due to their sensitivity to human tissue and other fluid materials. Application to NDE of solid materials, such as those utilized in the aerospace industry, has been limited due to the lower resolution and increased bandwidth of the measurements. With the recent development of measurement techniques and instrumentation appropriate for the NDE of solids, the sensitivity of NMR applied to solid materials has improved; as a result, increasing attention is now being given to the technique's ability to evaluate aerospace materials and structures. During this program [1], magnetic resonance techniques were found to be useful for evaluation of corrosion in aluminum and heat damage in composite materials. In a previous study [2], corrosion and heat damage were shown to be detectable using nuclear magnetic resonance (NMR). In this program, these phenomena were evaluated in greater detail using additional NMR parameters and the electron spin resonance (ESR) technique. BACKGROUND