No abstract

The reaction of di(1-naphthyl)methane (DNM) was investigated as a model reaction for coal liquefaction using Fe, Ni, and Pd/C both in the presence and in the absence of sulfur. The results show that Fe, Ni, and Pd/C mainly catalyzed DNM hydrogenation, whereas added sulfur, which was likely to react with Fe, Ni, and Pd/C to form their sulfides, retarded DNM hydrogenation but promoted DNM hydrocracking. According to the results, we consider that the metals predominately catalyzed biatomic hydrogen transfer, whereas their sulfides selectively promoted monatomic hydrogen transfer.

Temperature-programmed surface reaction (TPSR) of N′-nitrosonornicotine (NNN) was firstly reported on zeolite and ordered mesoporous materials. Among the catalysts SBA-15 and MCM-48 exhibited an activity much higher than zeolite NaY. They could also adsorb nitrosamines without interference of organic solvent, which will be helpful for environmental protection.

To compare the chemical differences between the medicinal and cultured oyster shells, their chemical profiles were investigated. Using the ultra performance liquid chromatography-electron spraying ionization-mass spectrometry (UPLC-ESI-MS), combined with principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA), the discrimination of the chemical characteristics among the medicinal and cultured oyster shells was established. Moreover, the chemometric analysis revealed some potential key compounds. After a large-scale extraction and isolation, one target key compound was unambiguously identified as caffeine (1) based on extensive spectroscopic data analysis (1D and 2D NMR, MS, and UV) and comparison with literature data.

Hydrocracking reactions of di(1-naphthyl)methane (DNM) and hydrogenated di(1-naphthyl)methanes (H-DNMs) were investigated at 300 °C to examine the relationship between structure and reactivity of the substrates. The results show that in the presence of Ni−S DNM is readily hydrocracked to naphthalene and 1-methylnaphthalene under pressurized hydrogen, while the more deeply DNM is hydrogenated, the more slowly the resulting H-DNMs are hydrocracked. The differences between DNM and H-DNMs and among the different H-DNMs in reactivity toward hydrocracking can be ascribed to the hydrogen-accepting abilities of ipso-carbons in the substrates, the stabilities of leaving arylmethyl radicals and the adsorption strength of the substrates on catalyst surface.

No abstract

Since a carbon disulfide-N-methyl-2-pyrrolidinone (CS 2 -NMP, 1: 1 v/v) mixture was found by Iino et al. to be an excellent mixed solvent for extraction of some bituminous coals at room temperature, 1 it has attracted great attention of many coal chemists. [2][3][4][5] On the basis of consideration that the mixed solvent may extract some coals more effectively at higher temperatures, we attempted to investigate coal dissolution behavior in the mixed solvent at elevated temperatures. The reaction between CS 2 and NMP is undesirable during coal extraction. So, we first investigated thermal interaction between CS 2 and NMP. We found unexpectedly that a significant amount of NMP was converted by reacting with CS 2 at elevated temperatures. In this communication, we present our preliminary results regarding the reaction of NMP with CS 2 .CS 2 and NMP were commercial reagents and were used without further purification. A prescribed amount of CS 2 and 5 mL of NMP were put into a 100 mL stainless steel, magnetically stirred autoclave. After being pressurized with nitrogen to 5 MPa at room temperature, the autoclave was heated to an indicated temperature within 10 min and kept at the temperature for a prescribed period of time. Then the autoclave was immediately cooled to room temperature in an ice-water bath. The reaction mixture was taken out from the autoclave and analyzed by GC (HP 6890), GC/MS (HP 6890/5973), and GC/FTIR (HP 6890/Nicolet IR-560).Only one product from the liquid phase was detected. Figure 1 shows the mass spectrum of the product. The molecular ion M + at m/z 115 undergoes the CH 3 -N bond cleavage to afford a fragmental ion at m/z 100 and undergoes ring cleavage to afford fragmental ions at m/z 73 and 42. Similar ring cleavage in the resulting fragmental ion at m/z 100 leads to the formation of the fragmental ions at m/z 58 and 42. The fragmental ion at m/z 87 is afforded by losing -CH 2 CH 2 -from M + , whereas the fragmental ion at m/z 82 results from the cleavage of the CdS and its adjacent C-H bonds in M + . The fragmental ions at m/z 85 and 30 are produced by ring cleavage in M + followed by hydrogen shift. The product was further identified by its infrared spectrum shown in Figure 2. No absorption bands in the 1775-1685 cm -1 range were observed, indicating no carbonyl group exists in the product. The existence of -CH 3 and -CH 2 -can be seen from their absorption bands at 2970, 2931, 2877, and 1462 cm -1 . The absorption band at 1508 cm -1 is attributed to >N-CdS moiety. The absorption bands at 1404, 1223, 1142, and 1088 cm -1 testify to the presence of CH 3 -N<. The strongest absorption bands at 1317 and 1296 cm -1 are ascribed to >CdS stretching vibrations. Therefore, the product was identified to be N-methylpyrrolidine-2-thione (NMPT), suggesting the oxygen atom in carbonyl of NMP was substituted by a sulfur atom in CS 2 during thermal reaction shown in Scheme 1. Nomura, M.; Murata, S.; Artok, L. Energy Fuels 1999, 13, 518-528. Figure 1. Mass spectrum of the product derived from the reaction...

No abstract