[Pyrolysates of novel latent fragrant compound 3,6-dimethyl-2,5-pyrazinedicarboxylic acid menthol ester].

In order to develop a new tobacco flavor released at high-temperature, the novel latent fragrant compound 3,6-dimethyl-2,5-pyrazinedicarboxylic acid menthol ester (DPAME) was synthesized by esterification using 2,3,5,6-tetramethylpyrazine and menthol as raw materials. In air atmosphere, the pyrolysis behavior of DPAME was investigated using an on-line pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) method at three temperature levels of 300, 600 and 900 degrees C, separately. The pyrolysis products were directly introduced into GC-MS and were qualitatively and semi-quantitatively analyzed. The results showed that a variety of aroma compounds of aldehydes, 3-p-menthene and menthol were released and identified at 300 degrees C. While at 600 degrees C and 900 degrees C, flavor alkene class, the alkyl pyrazines, menthol and 3-p-menthene were generated. And the types and relative amounts of pyrazines were significantly increased, at these two temperatures. Combined the analytical results of DPAME pyrolysates and the results of sensory evaluation of the cigarette, the possible pyrolysis mechanism was preliminarily speculated. The Py-GC-MS technique for the study of the pyrolysis products of DPAME was convenient and rapid. The investigation provided a reliable theoretical foundation for the perfume reinforcement technology in tobacco products, contributing to the development of cigarette products with better aroma and taste. This method is an accurate and quick way to study the pyrolysis products of latent fragrant substance.

Ionothermal synthesis and crystal structures of novel aluminum phosphates with in situ generated templates.

Protic ionic liquids (PILs) are a subgroup of ionic liquids and easily formed by proton transfer from a Brønsted acid to a Brønsted base. Two new crystalline aluminophosphates, [C5H16N2][Al(PO4)(HPO4)] (AlPO-PIL1) and [C5H16N2][Al2(OH)2 (PO4)2] (AlPO-PIL2), are successfully prepared for the first time from a protic ionic liquid, 3-dimethylaminopropylamine acetate. Their structures were determined from single-crystal X-ray diffraction data. It was found that HF in the reaction mixture is crucial in determining the selectivity of the phase. In the absence of HF, AlPO-PIL1 with a one-dimensional chain structure was synthesized by templating the protonated 3-dimethylaminopropylamine cation of the PIL. Upon addition of HF to the initial reaction mixture, AlPO-PIL2 was obtained by templating the protonated N,N'-dimethyl-1,3-propanediamine, which was in situ generated from the protonated 3-dimethylaminopropylamine through migration of methyl groups during the crystallization. AlPO-PIL2 has a novel layered structure with a 3-connected 4·8·8 two-dimensional network which has never been found in the previously reported layered aluminophosphates.