Cyanamides, preparation, thermally

The TPD apparatus consisted of a stainless steel flow system connected to a thermal conductivity cell. Catalyst samples of 0.1 g were placed in one arm of an L-shaped, 6 mm Vycor tube. A dual adsorption bed containing alumina and Oxy-Trap (Alltech) was placed in the other arm to prevent contamination by water and respectively. Frequent regeneration in and He was required. This in-situ adsorption bed was found necessary despite purification traps on all gas lines coming into the flow system. Pulses of 0.25 cc of a 10% mixture of CO in He were injected into the He carrier gas and passed over the pretreated catalyst at room temperature. All runs were programmed heated at a rate of 20 K min . The Pt catalysts, either commercial or laboratory produced, were prepared by the impregnation of chloroplatinic acid on Cyanamid s Aero 1000 alumina, except for two catalysts which were prepared by platinum diamino dinitrite impregnation. 

In this paper, we present the metastable a-polymorph of strontium carbodiimide as a novel pseudochalkogenide host lattice for divalent europium ions. Because of the high thermal inertness and cationic nitrogen coordination of this compound looks like a promising candidate for future applications. Furthermore, Sr-based compounds are ideal host lattices for divalent rare-earth-ions, simply because Sr " " is spectroscopically inactive, and Sr and Eu have comparable ionic rachi and identical charge. As a synthetic challenge, however, the preparation of phase-pure samples is required. Inspired by the reaction of EuN, BN, and NaN3 to form Eu3(NBN)2, and the synthesis of In2.24(NCN)3 from InBr and NaCN, we developed a new flux route based on the metal halide, alkaline cyanide, and alkaline azide, which act as precursors for the synthesis of structurally rather complex rare-earth and alkaline-earth cyanamides and... 

The PCN monomer was prepared by reaction of cyanamide with phenylisocyanate in alkaline solution at 15-18°C according to the literature [40]. The crude white powdered product was purified by recrystallization from an acetone-petroleum ether mixed solvent. The resulting colorless fine needles of phenylcarbamidonitrile melted at 134-136°C. Figure 5 shows its thermal behavior in differential scanning calorimetry (DSC, Dupout 1090) a sharp endothermic melting point peak appears... 

Oligomers end-capped with maleimide rings, which are known as bismaleimide (BMI) resins, exhibit thermal stability intermediate between epoxies and poly-imides. BMI systems are mainly used to fabricate structural composites capable of sustaining temperatures up to 230°C. Specific versions, such as American Cyanamid FM 32 and Ciba-Geigy Kerimid 601 have been developed to prepare adhesive compositions. Fig. 17 displays a typical constitutive unit of various commercial BMI resins based on bismaleimide 38, prepared from maleic anhydride 37 and 4,4 -methylenebisbenzeneamine (MDA) 34. 

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