Nitrogen Chemistry and Coke Transformation of FCC Coked Catalyst during the Regeneration Process.

Regeneration of the coked catalyst is an important process of fluid catalytic cracking (FCC) in petroleum refining, however, this process will emit environmentally harmful gases such as nitrogen and carbon oxides. Transformation of N and C containing compounds in industrial FCC coke under thermal decomposition was investigated via TPD and TPO to examine the evolved gaseous species and TGA, NMR and XPS to analyse the residual coke fraction. Two distinct regions of gas evolution are observed during TPD for the first time, and they arise from decomposition of aliphatic carbons and aromatic carbons. Three types of N species, pyrrolic N, pyridinic N and quaternary N are identified in the FCC coke, the former one is unstable and tends to be decomposed into pyridinic and quaternary N. Mechanisms of NO, CO and CO2 evolution during TPD are proposed and lattice oxygen is suggested to be an important oxygen resource. Regeneration process indicates that coke-C tends to preferentially oxidise compared with coke-N. Hence, new technology for promoting nitrogen-containing compounds conversion will benefit the in-situ reduction of NO by CO during FCC regeneration.

Ship-in-a-bottle synthesis of amine-functionalized ionic liquids in NaY zeolite for CO2 capture.

CO2 capture on solid materials possesses significant advantages on the operation cost, process for large-scale CO2 capture and storage (CCS) that stimulates great interest in exploring high-performance solid CO2 adsorbents. A ship-in-a-bottle strategy was successfully developed to prepare the [APMIM]Br@NaY host-guest system in which an amine-functionalized ionic liquid (IL), 1-aminopropyl-3-methylimidazolium bromide ([APMIM]Br), was in-situ encapsulated in the NaY supercages. The genuine host-guest systems were thoroughly characterized and tested in CO2 capture from simulated flue gas. It was evidenced the encapsulated ILs are more stable than the bulk ILs. These host-guest systems exhibited superb overall CO2 capture capacity up to 4.94 mmol g(-1) and the chemically adsorbed CO2 achieved 1.85 mmol g(-1) depending on the [APMIM]Br loading amount. The chemisorbed CO2 can be desorbed rapidly by flushing with N2 gas at 50 °C. The optimized [APMIM]Br@NaY system remains its original CO2 capture capacity in multiple cycling tests under prolonged harsh adsorption-desorption conditions. The excellent physicochemical properties and the CO2 capture performance of the host-guest systems offer them great promise for the future practice in the industrial CO2 capture.

SO3H-functionalized ionic liquid: efficient catalyst for bagasse liquefaction.

Liquefaction is a process for the production of biofuel or value-added biochemicals from non-food biomass. SO(3)H-, COOH-functionalized and HSO(4)-paired imidazolium ionic liquids were shown to be efficient catalysts for bagasse liquefaction in hot compressed water. Using SO(3)H-functionalized ionic liquid, 96.1% of bagasse was liquefied and 50.6% was selectively converted to low-boiling biochemicals at 543 K. The degree of liquefaction and selectivity for low-boiling products increased and the average molecular weight of the tetrahydrofuran soluble products decreased with increasing acidic strength of ionic liquids. Analysis of products and comparative characterization of raw materials and residues suggested that both catalytic liquefaction and hydrolysis processes contribute to the high conversion of bagasse. A possible liquefaction mechanism based on the generation of 3-cyclohexyl-1-propanol, one of the main products, is proposed.

Highly efficient selective oxidation of alcohols to carbonyl compounds catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen.

Efficient selective oxidation of alcohols to carbonyl compounds by molecular oxygen with isobutyraldehyde as oxygen acceptor in the presence of metalloporphyrins has been reported. Ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) showed excellent activity and selectivity for oxidation of various alcohols under mild conditions. Moreover, different factors influencing alcohols oxidation, for example, catalyst, solvent, temperature, and oxidant, have been investigated. In large-scale oxidation of benzyl alcohol, the isolated yield of benzaldehyde of 89% was observed.

[The surface adsorption and selective catalytic reaction of NO on Cu-ZSM-5 using in situ DRIFTS].

The prepared Cu-ZSM-5 catalyst presents higher activity at low temperature during the selective catalytic reduction (SCR) of NO, and the conversion from NO to N2 is 70.6% at 613 K. The in situ diffuse reflectance FTIR spectroscopy (in situ DRIFTS) is an important method for studying surface adsorption of catalyst and mechanism of catalytic reaction, and was used to study the surface adsorbed species and the selective catalytic reduction reaction of NO on Cu-ZSM-5 catalyst in the presence of propene as reductant, with excess O2 and at 298-773 K. Based on the in-situ DRIFTS, a reaction mechanism is proposed that on Cu-ZSM-5, NO is first transformed to a series of NO(x) surface adsorbates, then these species react with the activating species of propene (C(x)H(y) or C(x)H(y)O(x)) to form organo-intermediates, including a process from organo-NH to organo-CN again to organo-NO(x) (organo-nitro or organo-nitrito), and finally these key intermediates react to form nitrogen. The role of Cu is to promote NO(x) content. Propene is easily activated on Cu-ZSM-5 with oxygen, and furthermore, the presence of oxygen is necessary to form organo-NO(x) intermediates.

Ultrasonic chemical oxidative degradations of 1,3-dialkylimidazolium ionic liquids and their mechanistic elucidations.

A highly efficient process for oxidative degradation of 1,3-dialkylimidazolium ionic liquids in hydrogen peroxide/acetic acid aqueous medium assisted by ultrasonic chemical irradiation is, for the first time, described. It is shown that more than 93% of the 1,3-dialkylimidazolium cation with the corresponding Cl-, Br-, BF4- and PF6- counter-anions at a concentration of 2.5 mM can be degraded at 50 degrees C within 12 h while at 72 h the conversions approach 99%. A tentative mechanism for the degradation of these ILs is for the first time proposed through a detailed kinetic analysis of several characteristic transients and/or immediate products, which are identified during the ILs degradation using GC-MS. The results clearly indicate that three hydrogen atoms in the imidazolium ring are the first sites preferably oxidized, followed by cleavage of the alkyl groups attached to the N atoms from the ring. The nature of the alkyl chain length on the imidazolium ring and the type of counter anion do not seem to affect the degradation process. Further, selective fragmentations of C-N bonds of the imidazolium or derived ring lead to ring opening, forming degraded intermediates. It is also shown that acetoxyacetic acid and biurea are the final kinetically stable degraded products from the ILs under the degradation conditions.

[In situ diffuse reflectance FTIR spectroscopy characterization of titanium silicalite-1 catalytic oxidization of styrene].

The Stability of framework of titanium silicalite-1 (TS-1) was investigated by high temperature diffuse reflectance FT-IR spectroscopy (DRIFTS), and the results showed that the 960 cm(-1) peak belonging to Ti-framework was stabilized at 673 K, but the two peaks belonging to framework shifted to lower frequencies by about 13 cm(-1) at 673 K. The effect on the framework after H2O2 adsorption was discussed. The results showed that the 960 cm(-1) peak lowered and shifted to high frequencies by about 11 cm(-1), but it recovered with vacuum or heating up. It was suggested that the 960 cm(-1) peak characterizes Ti==O, and this explained why the 960 cm(-1) peak shifted to high frequencies well. TS-1 catalytic oxidization of styrene was investigated by in situ DRIFTS. The reaction process was detected and phenyl aldehyde was the main product. Based on in situ analysis, it was proposed that H2O2 was adsorbed on Ti in framework of TS-1 to form active center.

Selective oxidation of sulfides to sulfoxides catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride in the presence of molecular oxygen.

Highly efficient selective oxidation of sulfides to sulfoxides by molecular oxygen catalyzed by ruthenium (III) meso-tetraphenylporphyrin chloride (Ru(TPP)Cl) with isobutyraldehyde as oxygen acceptor has been reported. In large-scale experiment of thioanisole oxidation, the isolated yield of sulfoxide of 92% was obtained and the turnover number reached up to 92,000.

[In situ diffuse reflectance FTIR spectroscopy study of the selective catalytic reduction reaction of NO over Ag/SAPO-34 catalysis].

An in situ diffuse reflectance FTIR spectroscopy (DRIFTS) study of the selective catalytic reduction (SCR) of NO with propene in the presence of excess O2 was carried out over Ag/SAPO-34 catalyst. The SCR reaction was investigated at temperatures from 573 to 773 K, and the role of oxygen in the NO reduction process was determined by comparing experiments using an initial reaction mixture containing oxygen and without oxygen. The results show that both NO and propene are easily activated in oxygen. Furthermore, the presence of oxygen is necessary to form organo-NOx adsorbed species. Based on these experiments, a reaction mechanism is proposed that NO, propene and oxygen react to form organo-nitro and organo-nitrito adsorbed species as key intermediates, and then these intermediates decompose to nitrogen.

[The study of adsorption properties of SAPO-34 molecular sieve by in situ DRIFTS].

The adsorption of H2O, NH3 and NO in molecular sieve SAPO-34 was studied by in situ DRIFTS at temperatures from 298 K to 773 K. The results show that the phenomenon of adsorption is reversible for H2O, but not for NH3 and NO. The water in SAPO 34 is absolutely deadsorbed at 623 K and the bridged Si-OH-Al group is observed at 3,625-3,600 cm-1. It is found that SAPO-34 displays good adsorption-catalysis activity for NH3 and NO. After adsorbing NH3, the bridged hydroxyls disappear, but three peaks appear at 3,135, 3,032 and 1,399 cm-1 at 423 K, and reach their climax at 673 K. The height of the peaks are 3.9, 1.7 and 6.7 times as much as SAPO-34 framework peak's, respectively. A strong and sharp peak is also observed at 1,364 cm-1 after NO adsorption at room temperature, and it exhibit approximately the same intensity with the framework peak. Analysis of these peaks indicate that there could produce new species NO3-.

[Study on the SCR of NO over automobile exhaust catalyst Ag/SAPO-34].

The activity of Ag/SAPO-34 molecular sieve catalyst was investigated, and the selective catalytic reduction (SCR) of NO was studied by in-situ diffuse reflectance FTIR spectroscopy(DRIFTS). The results show that the prepared catalyst had high activity at low temperature and the conversion of NO reduction to N2 was about 70% at 3.6% O2 and 573K-673K of temperature. The catalysis activity rised with the concentration of C3H6 but light decrease with GHSV. Based on in-situ DRIFTS, a reaction mechanism was proposed that NO, propene and oxygen react to form organo-nitro and organo-nitro adsorbed species as key intermediates, then these intermediates were decompose to nitrogen. NO and propene were easily activated in oxygen. Furthermore, the presence of oxygen is necessary to form a series of intermediates.