Selective degradation reactions combined with MALDI analysis have been applied for molecular weight (MW) determination of polyether and polyester polyurethane (PUR) soft blocks. Selective degradation allows recovery of the polyols, and direct observation of the soft block oligomer distribution is possible for the first time by using MALDI. Ethanolamine is applied for polyether PUR degradation. MALDI analysis indicates that the recovered polytetrahydrofuran (pTHF) MW distribution is nearly identical to the unreacted pTHF material. Reduction in the ethanolamine reaction time allows observation of oligomer ions containing the diisocyanate linkage, which provide identification of the diisocyanate. Ethanolamine is not used for polyester PUR's degradation because the ester bonds will be cleaved. Therefore, phenylisocyanate is applied for polyester PUR degradation. Polybutylene adipate (pBA) oligomers were directly observed in the MALDI spectra of the degraded pBA-PUR samples. Comparison of the degraded pBA-PUR oligomer distribution with the unreacted pBA material indicates that low-mass oligomers are less abundant in the degraded pBA-PURs. Oligomer ions containing the diisocyanate linkage are also observed in the spectrum, providing a means for identifying the diisocyanate used for PUR syntheses. Size-exclusion chromatography (SEC) was combined with MALDI to provide accurate MW determination. Narrow MW fractions of the degraded and unreacted polyols were collected and analyzed by MALDI. This method allows precise calibration of the SEC chromatogram. The SEC-MALDI results provide significantly larger Mw and PD values than MALDI alone. Using SEC-MALDI, it was determined that the PD indexes of the pTHF and pBA samples are larger than the assumed values, which are based on the polyol synthesis reactions. The combination of selective degradation with SEC-MALDI, using either ethanolamine or phenylisocyanate, is a viable method for polyurethane polyol characterization.

The anodic C–H amination of aromatic compounds is a powerful and versatile method for the synthesis of aniline derivatives. By using boron‐doped diamond (BDD) anodes, a method initially described by Yoshida et al. for electron‐rich arenes was expanded to less‐activated aromatic systems e.g., simple alkylated benzene derivatives. Anodes based on sp3 carbon seem to be the key for the electrochemical amination reaction. The corresponding primary anilines are obtained in good yields. Despite the cationic intermediates of the electrolytic reaction tert‐butyl moieties are tolerated.

Infrared spectroscopy was used to study the structure and deformation behaviour of a series of model poly(ether-urethane) (PEU) elastomers. These materials contain (molecularly) uniform hard segments obtained from piperazine and the bischloroformate of 1,4-butanediol with a poly(oxytetramethy1ene) soft segment and contain no hydrogen bonding. Polarization infrared spectra were obtained simultaneously with stress-strain measurements during deformation. The orientation of hard and soft segments was measured using static and oscillatory strain. The results are consistent with a lamellar hard-domain structure in which lamellae orient in the stretching direction at low strain and are sheared apart at higher strains. The stress-strain and orientation behaviours were found to be highly dependent on the thermal history with annealed samples showing a higher degree of hard-segment order and resistance to strain-induced disruption. The PEU samples show an initial rapid and a later gradual relaxation of stress and orientation which occur upon step strain as the hard domains, which are not stabilized by hydrogen bonding, are disrupted under strain. The carbonyl stretching vibration was found to be sensitive to the hardsegment order. With increasing temperature or strain, an increase in a band component associated with a disordered structure was observed, along with a reduction of the hard-segment orientation at high strain as the hard domains were disrupted. Under cyclic deformation at 1,6 Hz reversible hard-segment orientation provides further evidence for lamellar rotation at small strains. Stressinduced crystallization is observed near 300% strain.

Purified methylenedianiline (MDA) regioisomers were structurally characterized and differentiated using tandem mass spectrometry (MS/MS), ion mobility-mass spectrometry (IM-MS), and IM-MS/MS in conjunction with computational methods. It was determined that protonation sites on the isomers can vary depending on the position of amino groups, and the resulting protonation sites play a role in the gas-phase stability of the isomer. We also observed differences in the relative distributions of protonated conformations depending on experimental conditions and instrumentation, which is consistent with previous studies on aniline in the gas phase. This work demonstrates the utility of a multifaceted approach for the study of isobaric species and elucidates why previous MDA studies may have been unable to detect and/or differentiate certain isomers. Such analysis may prove useful in the characterization of larger MDA multimeric species, industrial MDA mixtures, and methylene diphenyl diisocyanate (MDI) mixtures used in polyurethane synthesis.

The twofold electrochemical amination reaction of polycyclic arenes, such as naphthalene (4), via Zincke intermediates is demonstrated for the first time. The installation of nitrogen functionalities occurs regioselectively in positions 1 and 5 of naphthalene (4). The key for this electroconversion is boron‐doped diamond as the anode material. The method of the multi‐amination reaction is expanded to other aromatic substrates. A detailed study is provided, covering electrolysis parameters such as anode material, electrolyte system, current density, separator, and so forth. Despite the moderate yields, this approach offers the first direct electrosynthetic access to diaminated products.