Liquid-Phase Partial Hydrogenation of Phenylacetylene at Ambient Conditions Catalyzed by Pd-Fe-O Nanoparticles Supported on Silica

Catalysts with no hazardous or toxic components are required for the selective hydrogenation of acetylenic bonds in the synthesis of pharmaceuticals, vitamins, nutraceuticals, and fragrances. The present work demonstrates that a high selectivity to alkene can be reached over a Pd-Fe-O/SiO2 system prepared by the co-impregnation of a silica support with a solution of the metal precursors (NH4)3[Fe(C2O4)3] and [Pd(NH3)4]Cl2 followed by thermal treatment in hydrogen or in air at 400 °C. A DRIFT spectroscopic study of CO adsorption revealed large shifts in the position of the Pdn+-CO bands for this system, indicating the strong effect of Fen+ on the Pd electronic state, resulting in a decreased rate of double C=C bond hydrogenation and an increased selectivity of alkyne hydrogenation to alkene. The prepared catalysts consisted of mono- and bimetallic nanoparticles on an SiO2 carrier and exhibited a selectivity as high as that of the commonly used Lindlar catalyst (which contains such hazardous components as lead and barium), while the activity of the Fe-Pd-O/SiO2 catalyst was an order of magnitude higher. The hydrogenation of a triple bond over the proposed Pd-Fe catalyst opens the way to selective hydrogenation over nontoxic catalysts with a high yield and productivity. Taking into account a simple procedure of catalyst preparation, this direction provides a rationale for the large-scale implementation of these catalysts.

[Long-term results of radical surgery treatment of patients with bladder cancer]

PURPOSE

To investigate long-term results after radical cystectomy in patients with bladder cancer.

MATERIALS AND METHODS

Since 1997 to 2020 yy. we have performed 404 radical cystectomy with different methods of derivation for patients with bladder cancer in our clinic. There were 342 (86,4%) men and 62 (13,6%) women. Laboratory study, ultrasound, X-ray, CT. MRI investigations were performed in all patients.

RESULTS

Mortality rate was 2,9%. Early and late postoperative complications have occurred in 136 (33,6%) and 98 (41,8%) cases, respectively. Local recurrence has occurred in 33 (8,5%) patients. 10-years overall and cancer-specific survival were 43,4% and 47,2%, respectively. In lymph-negative patients 2-years and 5-years overall survival were 81,2% and 67,2%, respectively. In lymph positive patients 2-years and 5-years overall survival were 46,9% and 13,9%, respectively. In lymph-negative patients 2-years and 5-years cancer-specific survival were 83,6% and 70,7%, respectively. In lymph positive patients 2-years and 5-years cancer-specific survival were 51,0% and 15,1%, respectively. Overall and cancer -specific survival decreased according to increasing pT-stage and histopathologic grade.

CONCLUSIONS

pT-stage (pT), lymp nodes status (pN), histopathologic grade ( pG) have a significant independent influence on overall and cancer-specific survival of bladder cancer patients after radical cystectomy.

Novel Fe-Pd/SiO2 catalytic materials for degradation of chlorinated organic compounds in water

Novel reactive materials for catalytic degradation of chlorinated organic compounds in water at ambient conditions have been prepared on the basis of silica-supported Pd-Fe nanoparticles. Nanoscale Fe-Pd particles were synthesized inside porous silica supports using (NH4)3[Fe(C2O4)3] and [Pd(NH3)4]Cl2 or Pd acetate as reaction precursors. According to temperature programmed reduction (TPR) studies, Pd introduction decreased the reduction temperature of the supported Fen+ species and nearly complete reduction with H2 was observed at 400 °C. The successful surface loading with Pd was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Characterization of the samples by X-ray diffraction (XRD) and X-ray absorption near-edge structure + extended X-ray absorption fine structure (XANES + EXAFS) verified the presence of highly dispersed Pd0, Pdx Fe1–x and Fe0 phases. Reduction of the supported precursors in hydrogen resulted in materials that were highly active in perchloroethene (PCE) degradation and 2-chlorobiphenyl (2-ClBP) dechlorination. It was found that highly dispersed amorphous Fe-Pd bimetallic nanoparticles on silica support showed superior catalytic activity against PCE dechlorination in comparison to the free-standing Fe-Pd nanoparticles. For the samples with the same Fe content, the conversion of chlorinated organics as well as the stability increased with the Pd loading, e.g., the most effective degradation of PCEs and 2-ClBP was achieved at a Pd loading of 2.3–3.2 wt. %.

Pd-Fe nanoparticles stabilized by chitosan derivatives for perchloroethene dechlorination

A series of chitosan-stabilized Pd-NZVI (nano-zero-valent-iron) catalysts for dechlorination with variation in their composition and in the nature of the polymer has been prepared. The synthesis procedures and palladium and chitosan contents were optimized. It was demonstrated by the XPS method that Fe and Pd in Fe-Pd/chitosan samples exist in the metallic state. The positive shift of the binding energy as compared with the bulk metal shows that the iron metal in the surface layers exists as very small nanoparticles. The prepared materials were characterized also by the XAS method. The presence of O and N atoms in the first coordination shell of the central Fe atom in the Fe-Pd/chitosan samples certifies the binding of the Fe metal particles with the chitosan surface via OH and NH(2) groups. The samples are characterized by the high stability of the nanoparticles as compared to unstabilized Pd-NZVI. The materials were tested to evaluate their catalytic activity in the perchloroethene (PCE) dechlorination reaction. Some samples of chitosan-stabilized Pd-NZVI revealed a good performance in PCE degradation as compared to unstabilized Pd-NZVI.

[Urodynamics of artificial urinary bladder]

Radical cystectomy with creation of orthotopic reservoir from various segments of gastrointestinal tract was made in 120 patients (99 males, 21 females, age 37-74 years) with muscular-invasive cancer of the urinary bladder (UB) in 1996-2004. Replacement of UB was made according to the Studer and Hautmann method in 38 and 27 patients, respectively. S-cystoplasty was performed in 31 patients. The gastric segment was used for creation of the reservoir in 24 patients. Three patients died. Three to twelve month follow-up recorded the best functional results in patients after Studer cystoplasty.

[Replacement of the urinary bladder by the stomach body]

In the period from 2001 through 2004 plasty of the urinary bladder was performed in 24 patients using a. et v. gastroepyploici dexter. Mean age of the patients (18 men and 6 women) was 58.2 years. Gastrocystoplasty in 18 patients was performed after radical cystectomy for urinary bladder cancer, in 6 patients for neurogenic and small urinary bladder. The authors' original modification with a complete transversal resection of the stomach body taken together with the lesser curvature was used in operations on 10 patients. Early postoperative complications developed in one patient, late ones--in two patients, there were no lethal outcomes. Positive functional results were noted in all patients within the terms of observations from 2 through 22 months. Good quality of life was noted in all of them.

[Orthopic plastic repair of the urinary bladder with a gastric segment]

Urinary bladder plastic repair with a gastric segment on a. et v. gastroepyploici dex was made in 22 patients (18 males, 4 females, mean age 58.2 years) from November 2001 to June 2003. Gastrocystoplasty was made in 17 patients after radical cystectomy for urinary bladder cancer, and in 5 patients with neurogenic and small urinary bladder. Three patients have undergone surgery in our modification with a complete cross resection of the gastric body with the lesser curvature. Lethal outcomes were absent. Follow-up for 2-22 months demonstrated that all the patients achieved positive functional results and good quality of life.