Silver (Ag+) salts adsorbed on amorphous silica or mesoporous SBA-15 extract dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me2DBT) from simulated, hydrotreated petroleum feedstocks.

The complexes, CpRu(CO)2(BF4) and [CpFe(CO)2(eta2-2-methylpropene)][BF4], react with dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me2DBT) to give [CpRu(CO)2(DBT)][BF4] and [CpFe(CO)2(4,6-Me2DBT)][BF4], whose structures were established by X-ray diffraction studies. The same types of products are obtained when dibenzothiophenes react with CpRu(CO)2(BF4) and [CpFe(CO)2(THF)][BF4] that are adsorbed on the mesoporous silica SBA-15. DRIFT and XPS studies indicate that CpRu(CO)2(BF4) and [CpRu(CO)2(DBT)][BF4] are adsorbed on the SBA-15 by hydrogen-bonding of the BF4- anions to surface Si-O-H groups. CpRu(CO)2(BF4)/SBA-15 removes 99% of the DBT in a 45% toluene/55% hexanes simulated petroleum feedstock. This solid phase extractant is less successful for sterically-hindered 4,6-Me2DBT, as only 72% of it is removed. The results show that CpRu(CO)2(BF4) can be immobilized by adsorption on mesoporous silica and that it reacts with dibenzothiophenes in the adsorbed form, CpRu(CO)2(BF4)/SBA-15, in much the same way that it reacts in solution.

In an effort to demonstrate that Ru(NH3)5(H2O)2+ can be used to remove dibenzothiophene from hydrotreated petroleum feedstocks, this metal complex was reacted with a variety of thiophenes (Th*), including dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me2DBT) to give complexes of the type Ru(NH3)5(Th*)2+. This ability of Ru(NH3)5(H2O)2+ to bind to thiophenes has been used in an extraction process in which a solution of Ru(NH3)5(H2O)2+ in 70% DMF and 30% H2O is contacted with a simulated petroleum feedstock (45% toluene/55% hexanes) containing 400 ppm of DBT. One extraction removes 50% of the DBT from the feedstock phase as Ru(NH3)5(DBT)2+, which is present in the DMF/H2O phase. Five successive extractions reduce the amount of DBT in the simulated feedstock from 400 to 25 ppm. The Ru(NH3)5(H2O)2+ extractant can be regenerated from the Ru(NH3)5(DBT)2+ either by air-oxidation followed by H2-reduction or by displacement of the DBT by adding H2O to the DMF/H2O phase. Extraction of 4,6-Me2DBT from the simulated feedstock using Ru(NH3)5(H2O)2+ in 70% N,N-dimethylacetamide and 30% H2O was less successful as the 4,6-Me2DBT concentration was only reduced from 400 to 340 ppm.

Human urine specimens that were determined to be presumptively positive for oxycodone and its metabolite, oxymorphone, by immunoassay screening were assayed using fast gas chromatography-mass spectrometry to positively identify and quantify the oxycodone and oxymorphone present. Urine specimens were first spiked with deuterated internal standards, oxycodone-d(3) and oxymorphone-d(3), subjected to acid hydrolysis, and then extracted using a positive-pressure manifold and mixed-bed solid-phase cartridge extraction methodology. Extracts were derivatized using methoxylamine and acetic anhydride. The acetylated-oxime derivatives of oxycodone and oxymorphone were identified and quantified using a selective ion monitoring (SIM). The method was found to be linear for both analytes to 1600 ng/mL, and limits of detection for oxycodone and oxymorphone were found to be 40 ng/mL and 20 ng/mL, respectively. Interlaboratory data comparisons (n = 40) showed correlation coefficients of 0.9999 and 0.9997 for oxycodone and oxymorphone, respectively. Twelve semisynthetic, structurally similar compounds at concentrations of 5000 ng/mL were assayed in the presence of oxycodone and oxymorphone and found not to interfere with identification and quantitation by this method. Finally, exact mass and tandem mass spectrometry techniques were employed to elucidate the structures of the SIM ions.

The dihydride {(η5-C5H3)2(SiMe2)2}W2(CO)6(H)2 (1), which contains a linked dicyclopentadienyl ligand, reacts with Ph3C+ to give [{(η5-C5H3)2(SiMe2)2}W2(CO)6(μ-H)]+ (2H + ). The W−H−W bond in 2H + is cleaved upon reaction with I- to give {(η5-C5H3)2(SiMe2)2}W2(CO)6(H)(I) (3). Crystal structures of [{(η5-C5H3)2(SiMe2)2}W2(CO)6(μ-H)]+ (2H + ) and its unprotonated analogue {(η5-C5H3)2(SiMe2)2}W2(CO)6 (2) are also reported and discussed.