Rate-determining stage in NO SCR with propane on low-exchanged Cu-ZSM-5 catalyst

The kinetics of the NO SCR with propane has been studied on a low-exchanged Cu-ZSM-5 catalyst. The study of the kinetics of individual reaction stages (2-nitrosopropane isomerization to acetone oxime and reaction of adsorbed acetone oxime with gaseous NO) has shown that the NO reaction with acetone oxime is the rate-determining stage in the whole chain of transformations leading to the formation of molecular nitrogen in the low-temperature region below 300 °C. The kinetic analysis of the reaction has revealed that at the temperatures above 300 °C propane plays a more important role

FTIR study of aceton oxime interaction with H-ZSM-5 and Cu-ZSM-5

Copper based catalysts are of great importance as catalysts for NO removal from exhaust industrial gases. Earlier authors have shown that NO reaction with acetone oxime (AO) is the rate determining step of NO catalytic reduction by propane over Cu-ZSM-5 catalyst at temperatures below 300°C. Aim of the present work is to clarify the peculiarities of acetone oxime coordination over surface of H-ZSM-5 zeolite and that doped with Cu(II) and Cu(I)-cations. We studied AO coordination in CCl4 solutions and then data obtained were used for analysis of spectra of AO adsorbed on pure zeolite and that dopped with Cu (I) and Cu (II) cations. It was shown that there are monomers and several associates of AO in CCl4 solution differing in size and type of bonding with their own characteristic bands in IR spectra. The spectrum of acetone oxime adsorbed on pure zeolite includes non symmetrical band at 1710 cm-1 due to AO strongly bonded with zeolite surface through H-bond. There are four AO adspecies on zeolite dopped with copper with two different types of AO coordination to Cu(I) or to Cu(II) cations: one with participation of O atom and another one with N atom. Complexes of AO with Cu(I) ions are much more stable then those with Cu(II) ions.</p

Propane and oxygen action on NOx adspecies on low-exchanged Cu-ZSM-5

A surface intermediate with a C/N ratio close to 3 has been shown by TPD to form at co-adsorption of NO and propane as well as NO, propane and O2 on low-exchanged Cu-ZSM-5. The adsorption of NO, propane and oxygen has been studied to evaluate their effect on the formation of this complex. Its formation is accompanied by a decrease in the concn. of surface nitrite-nitrate. The kinetics of nitrite-nitrate adspecies formation as a function of the reagents concn. and temp. has been investigated. Some NO adspecies have been found to decomp. yielding N2O

. Chronic kidney disease in patients with chronic back pain taking non-steroidal anti-inflammatory drugs

The aim of the study was to evaluate the incidence of chronic kidney disease (CKD) in patients with chronic back pain and nonsteroidal anti-inflammatory drugs (NSAIDs) intake not less than a year, and to study the interrelation between CKD, peculiarities of pain and its treatment. Material and Methods. 91 patients with axial spondyloarthri-tis — ax-SpA(ankylosing spondylitis and non-radiographic ax-SpA) and 35 patients with degenerative diseases of the spine (DDS) with NSADs intake not less than 1 year were involved in the study. The control group included healthy volunteers who did not took NSAIDs during the last year (n=51). By age, gender, factors of cardiovascular risk, GFR in patients with ax-SpA, DDS and controls were comparable. The activity of pain was evaluated according to the accepted recommendations. The index of NSAID intake as calculated for the preceding year. Results. GFR in patients with ax-SpAwas 87,0 [77,25; 102,0] ml/min/1,73 m2, 11 (18%) patients showed a reduction in GFR of less than 60 ml/ min/1,73m2. In patients with DDS GFR was 87,5 [65,5; 97,0] ml/min / 1,73 m 2 (p=0,27), decreased GFR of less than 60 ml/min / 1,73 m2 was detected in 3 (15%) patients. The ratio of albumin / creatinine urine in patients with ax-SpA was 35,8 [25,46; 43,4] mg/g, in patients DDS —207,1 [91,66; 244,59] mg/g (p<0,0001), in healthy individuals —25,45 [17,34; 33,65] mg/g. Conclusions. Patients with chronic back pain taking NSAIDs for a long time have revealed GFR, comparable with healthy people, and increased urine albumin. Patients with degenerative diseases of the spine have a greater index of albumin in urine than patients with ax-SpA