Catalytic Properties of Ni-Mo Carbide and Nitride Phases Supported on SBA-15 and -16 in the Hydrodesulfurization of DBT

In this paper, the incorporation of carbide and nitride phases supported on mesoporous materials like SBA type is described in order to obtain a better material than commercial catalysts (NiMoS/Al2O3, Sg=269 m2.gr-1) specifically in the HDS of dibenzothiophene. The XRD patterns exhibit the presence of carbide and nitride phases in each series, respectively. In the nitride materials, the presence of oxide phases was more evident than in the carbide catalysts. The principal product was biphenyl (BF) for all the analyzed series. This behavior suggests that the DBT desulphurization pathway for the carbide materials was similar to that of sulfide catalysts. Bicyclohexyl (BCH) was analyzed as a product, and cyclohexylbenzene traces (CHB) were determined in a single catalyst (NiMoC-2%P/SBA-16). This was attributed to the hydrogenation character of carbide catalyst reported previously.

Specificity and Non-Specificity in the Sensitized CO2-Laser-Induced Reaction of Tetrachloroethene

Previous workers have investigated the reaction of tetrachloroethene using thermal initiation and CO2-laser initiation via sensitizing species. In both instances, the principal product was found to be hexachlorobenzene. One group reported evidence of laser specificity in this reaction, in that BCl3 acted as a sensitizer to produce hexachlorobenzene as the principal product, but SF6 and BBr3 did not. We have found that specificity is highly dependent on reaction conditions. We reproduced the previous results using similar experimental conditions, but under different conditions, we found that the specificity is lost, with all three sensitizers which we used (BCl3, SF6, and SiF4) sensitizing the reaction to produce mainly hexachlorobenzene. There were some differences among the sensitizers, as, for example, the fact that SF6 produced the most nearly pure hexachlorobenzene product.

Retreat from Progress

Salisbury ironmakers throve by selling wrought iron rather then cast iron through the first half of the nineteenth century. Their finery forges and puddling works converted nearly all of the pig produced by the district’s furnaces to bar iron or forged products. However, by the 1860s, when the district’s ironmasters were smelting up to 11,800 tons of pig iron per year, they converted little of it to wrought iron. The demise of the forges left just one principal product, cast iron used mainly for railroad car wheels. Milo Barnum and Leonard Richardson had started making railroad castings in 1840. When Milo Barnum retired in 1852, his son W. H. Barnum took his place in the partnership with Richardson. The partners expanded the business by acquiring the Beckley and Forbes furnaces in 1858 and 1862, respectively, from the Adam family in East Canaan. Upon Leonard Richardson’s death, Barnum and the Richardson heirs reconstituted the business as the Barnum-Richardson Company, the firm that gradually gained control of all mines and blast furnaces in the northwest, except for the Kent furnace. A new railway facilitated the Barnum-Richardson operations. Dedicated residents of the northwest, in the face of much skepticism, raised the capital needed to build the Connecticut Western Railroad from Hartford to State Line, where it joined with the Dutchess & Columbia line running to Beacon, New York. Salisbury residents eagerly awaited its 1871 completion: they wanted to be rid of the heavy ore wagons that kept their roads a rness passing from Ore Hill to the furnaces in East Canaan. The Connecticut Western passed through Winsted, traversed difficult terrain in Norfolk, and crossed the Housatonic Railroad at Canaan, where the two companies built a handsome union station . Railroad enthusiasm also led residents in the northwest to propose impractical schemes. The Shepaug Railroad had been completed in 1872 from Danbury to Litchfield. A correspondent writing to the Connecticut Western News that year proposed extension into the Salisbury district.

Characterization of Two Novel Propachlor Degradation Pathways in Two Species of Soil Bacteria

ABSTRACT Propachlor (2-chloro-N-isopropylacetanilide) is an acetamide herbicide used in preemergence. In this study, we isolated and characterized a soil bacterium, Acinetobacter strain BEM2, that was able to utilize this herbicide as the sole and limiting carbon source. Identification of the intermediates of propachlor degradation by this strain and characterization of new metabolites in the degradation of propachlor by a previously reported strain ofPseudomonas (PEM1) support two different propachlor degradation pathways. Washed-cell suspensions of strain PEM1 with propachlor accumulated N-isopropylacetanilide, acetanilide, acetamide, and catechol. Pseudomonas strain PEM1 grew on propachlor with a generation time of 3.4 h and aKs of 0.17 ± 0.04 mM.Acinetobacter strain BEM2 grew on propachlor with a generation time of 3.1 h and a Ks of 0.3 ± 0.07 mM. Incubations with strain BEM2 resulted in accumulation of N-isopropylacetanilide,N-isopropylaniline, isopropylamine, and catechol. Both degradative pathways were inducible, and the principal product of the carbon atoms in the propachlor ring was carbon dioxide. These results and biodegradation experiments with the identified metabolites indicate that metabolism of propachlor by Pseudomonas sp. strain PEM1 proceeds through a different pathway from metabolism byAcinetobacter sp. strain BEM2.

Photodecarbonylation of chiral cyclobutanones

Triplet photosensitized irradiation of 2(S),3(R)-bis[(benzoyloxy)methyl]cyclobutanone gave optically pure (−)E-1(S),2(S)-bis(benzoyloxymethyl)cyclopropane as a major product in the nonpolar fraction along with its stereoisomer and cycloelimination products. The absolute stereochemistry of the chiral cyclopropane was established by independent synthesis and X-ray crystal structure determination of a synthetic precursor. The distribution of decarbonylation and cycloelimination products was inversely dependent on the concentration of the substrate. Irradiation of the same ketone in tetrahydrofuran or benzene gave mostly cycloelimination products. Addition of Michler's ketone increased the ratio of photodecarbonylation, suggesting a triplet state pathway for this process. This was corroborated by the addition of dicyanoethylene, which showed significant quenching of photodecarbonylation. Irradiation of 2(S)-[(benzoyloxy)methyl]cyclobutane in acetone gave the corresponding cyclopropane as the principal product. Keywords: photodecarbonylation, chiral cyclopropanes, cyclobutanones, triplet sensitization.

Flash Vacuum Pyrolysis of [2,3-13C2]Triphenylene-2,3-dicarboxylic Anhydride: Formation of Labelled Cyclopent[hi]acephenanthrylene and Triphenylene

Flash vacuum pyrolysis (f.v.p.) of [2,3-13C2]triphenylene-2,3-dicarboxylic anhydride (c. 22·5% 13C2) at 950°C gave a pyrolysate which was analysed by 13C n.m.r. spectroscopy. The principal product was [2,3-13C2]triphenylene. The second major product was a 1 : 2 : 1 mixture of [4,7- 13C2]-, [4,6-13C2]- and [5,6-13C2]-cyclopent[hi]acephenanthrylene.

The Role of Elimination Processes in the Reaction of Substituted Ureas and Thioureas with Chlorides of Mono-and Bifunctional Acids

The reaction of phthaloyl chloride 2 with 1,3-dimethylurea 1 in dichloromethane at room temperature leads to the formation of N ,N -1,1'-phthaloyl-bis(1,3-dimethylurea) 3 whereas in refluxing solvent N-methyl-phthalimide 4 is the principal product. The reaction of 1,3- bis(trimethylsilyl)-1,3-dimethylurea 5 separately with phthaloyl- 2, 4-nitrobenzoyl- 6, and 5-chlorothiophene-2-carbonyl chloride 9 results in the formation of 1,3-phthaloyl-1,3-dimethylurea 7, 1,3-bis(4-nitrobenzoyl)- 1,3-dimethylurea 8, and N,N-bis(5-chlorothiophene- 2-carbonyl)-N-methylamine 12, respectively. The reaction of N,N-bis- (trimethylsilyl)acetamide 11 with 9 furnished N,N-bis(5-chlorothiophene-2-carbonyl)-acetamide 13, while the reaction of 13 with 1,3-dimethylthiourea 10 afforded 1.3-dimethyl-1,3- bis(5-chlorothiophene-2-carbonyl)thiourea 14. The structures of 3 and 12 were confirmed by low temperature X-ray crystallography. Both display crystallographic twofold symmetry.