C10 C20 Research Articles

Effect of calcination temperature of alumina supports on the wax hydrocracking performance of Pd-loaded mesoporous alumina xerogel catalysts for the production of middle distillate

Abstract Selective production of middle distillate (C10–C20) from synthesis gas (CO + H2) through wax hydrocracking was carried out in a dual-bed reactor. Co/TiO2 catalyst was used in the first-bed reactor to produce wax (C21+) from synthesis gas, and Pd-loaded mesoporous alumina xerogel (denoted as Pd/XA) catalysts were used in the second-bed reactor to produce middle distillate through wax hydrocracking. The effect of calcination temperature of mesoporous alumina xerogel supports on the wax hydrocracking performance of Pd/XA catalysts was investigated. The increment of middle distillate selectivity increased with increasing medium acidity of Pd/XA catalyst. Among the Pd/XA catalysts, the Pd catalyst loaded on mesoporous alumina xerogel support calcined at 800 °C retained the highest medium acidity, and at the same time, showed the best catalytic performance in the hydrocracking of wax.

Characteristics of the thermal decomposition of biomass and numerical simulation for the gasification of decomposed mixtures

AbstractAs an initial step in clarifying the mechanisms of the combustion and gasification of biomass, fundamental experiments on the thermal decomposition and numerical simulation for the elementary reaction of decomposed chemical species have been performed. In the experiment, various kinds of biomass particles were rapidly heated by applying an electrically induced magnetic field to the metal tray on which the object particles had been placed. It was clarified that for the two decomposition temperatures of 590 and 1040 °C investigated, the relationship between decomposition rate and heating time was the same, but that the components of the decomposed species were substantially different; the mole fraction of C6–C9 components for the low temperature of 590 °C was 3 to 10 times greater than that corresponding to 1040 °C. Furthermore, a close relationship was ascertained between the percentage of heavy species (C10–C20) and the amount of lignin contained in the biomass. Numerical simulation indicated that these heavy species could decompose to C1 and H2 at over 1000 °C with H2O acting as the oxidation agent, and that the effect of H2O under atmospheric pressure reaches a maximum at PH2O–0.7 atm. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(8): 527–538, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20139

Utilization of Microporous and Mesoporous Materials as Supports of Cobalt Catalysts for Regulating Product Distributions in Fischer–Tropsch Synthesis

Abstract The utilization of different types of microporous and mesoporous materials as the supports of cobalt catalyst for Fischer–Tropsch synthesis could produce hydrocarbon fuels with different distributions. Among various catalysts investigated, Co/beta and Co/SBA-15 exhibited the highest selectivities to C5–C9 (gasoline fuel fraction) and C10–C20 (diesel fuel fraction) hydrocarbons, respectively.

Effect of Vanadium Promotion on Activated Carbon-Supported Cobalt Catalysts in Fischer–Tropsch Synthesis

The effect of vanadium promotion on activated carbon (AC)-supported cobalt catalysts in Fischer–Tropsch synthesis has been studied by means of XRD, TPR, CO-TPD, H2-TPSR of chemisorbed CO and F-T reaction. It was found that the CO conversion could be significantly increased from 38.9 to 87.4% when 4 wt.% V was added into Co/AC catalyst. Small amount of vanadium promoter could improve the selectivity toward C10–C20 fraction and suppress the formation of light hydrocarbon. The results of CO-TPD and H2-TPSR of adsorbed CO showed that the addition of vanadium increased the concentration of surface-active carbon species by enhancing CO dissociation and further improved the selectivity of long chain hydrocarbons. However, excess of vanadium increased methane selectivity and decreased C5+ selectivity.

Abundant non-hydrocarbons in crude oils from the western Qaidam Basin, northwest China

The non-hydrocarbon fraction of immature-low maturity crude oils from the western Qaidam Basin which were formed in the source beds deposited in highly saline and strongly reducing environments were analyzed by GC-MS to determine their compositions. Abundant fatty acids, alkanols, fatty acid glycerol monoesters, and stenols were identified. Geochemical analyses suggested that these compounds were largely originated from the oil source rocks. The linear compounds consist primarily of the short-chain homologues (C10–C20). The C27–C29 sterols detected were dominated by C27 stenols. The molecular characteristics suggest that algae and bacteria were the major source organism. The presence of abundant fatty acid glycerol monoesters suggests that the biological lipids, particularly bacterial phospholipids were important contributors to the formation of the crude oils studied. The existence of abundant unsaturated linear compounds, stenols and high CPI values of linear non-hydrocarbon compounds is consistent with the low maturity of these crude oils.

Extending surface science studies to industrial reaction conditions: mechanism and kinetics of methanol oxidation over silver surfaces

The selective oxidation of CH3OH to H2CO over the noble metals Cu, Ag and Au represents one of the oldest industrial catalytic technologies dating back to the 1880s [1,2] and also the first non-Pt based catalytic industrial process. Initially, the catalyst employed for methanol oxidation was metallic Cu and subsequent research three decades later comparing the noble different metal catalysts found that Ag was the most efficient catalyst for this reaction. The commercial Ag catalysts are unsupported and are in the form of pure needles, wires or gauzes and are of very high purity (99.999% Ag) with very low surface areas (BET 0:1 m/g). Currently, more than 50% of the world s H2CO is manufactured employing metallic Ag catalysts. Bulk mixed iron-molybdate catalysts account for the remaining H2CO production and commercially introduced in the middle of the 20th century. The advantage of the Ag-based technology is that it is a very flexible and simple process to start, operate (adiabatic reaction conditions), shut down and change the catalyst. Analogous alcohol oxidation reactions over the noble metal catalysts are also employed in the chemical industry to synthesize higher molecular weight aldehydes such as C10–C20 fragrances. The proposed reaction mechanism of methanol oxidation over Ag catalysts has also undergone significant changes over the years and has attracted much attention in the past 25 years by many leading surface science and catalysis research groups (more than 250 publications, which corresponds to an average of 10 papers/year). The initial proposed mechanism consisted of two sequential steps:

A combined RFLP-SSR-AFLP map of tetraploid cotton based on a Gossypium hirsutum x Gossypium barbadense backcross population.

An interspecific Gossypium hirsutum x Gossypium barbadense backcross population of 75 BC1 plants was evaluated for 1014 markers. The map consists of 888 loci, including 465 AFLPs, 229 SSRs, 192 RFLPs, and 2 morphological markers, ordered in 37 linkage groups that represent most if not all of the 26 chromosomes, altogether spanning 4400 cM. Loci were not evenly distributed over linkage groups, and 18 of the 26 long groups had a single dense region. This paper proposes a partially revised list of the 13 pairs of homoeologous A/D chromosomes of the 2n = 4x = 52 tetraploid cotton genome. The major revisions, which involve the c3-c17, c4-c22, c5-D08, and c10-c20 homoeologous pairs, are based on the mapping of 68 SSR and RFLP loci with a known chromosome assignment, as well as on comparative alignments with previously published G. hirsutum x G. barbadense maps. The overall congruency in the locus orders and distances of common SSR and RFLP loci in these maps allows for an estimation of the consensus length that reaches a minimum of 5500 cM, and is encouraging for future efforts aimed at developing an integrated map of cultivated cotton. The present map also provides a firm framework for precision mapping of Mendelian components of quantitative traits in cotton

A new selective SPME fiber for some n‐alkanes and its use for headspace sampling of aqueous samples

AbstractThis contribution presents a new porous solid phase microextraction (SPME) fiber based on cellulose acetate and polyvinyl chloride (PVC) coated on a metallic base. The proposed fiber is selective for n‐alkanes higher than C10, especially for C12–C15. PVC acts as a binder and surface modifier of the fiber. Fiber preparation can be completed in less than 15 min. High capacity, chemical, thermal, and mechanical durability, low cost, and no occurrence of additional peaks in chromatograms are further advantages of the proposed fiber. The relative standard deviations obtained from a single fiber are less than 9% for all analytes. The fiber‐to‐fiber reproducibility is better than 18%. After optimizing experimental conditions such as fiber composition, extraction time, desorption temperature, solution volume, salting out effect, etc. the fiber can be used for sampling from the headspace of aqueous solutions containing n‐alkanes (C10–C20) in the μg/L concentration range. Detection limits of 50–150 μg/L are obtained on use of capillary gas chromatographic separation and flame ionization detection. The microextraction procedure is rapid and equilibration takes less than 20 min.

Quantitation of fatty acids and hydroxy fatty acids by gas chromatography/mass spectrometry. Predictively useful correlations of relative response factors with empirical formula

AbstractRelative response factors (molar sensitivities relative to dibutyl phthalate) for homologous series of n‐alkanes (C12C26), trimethylsilyl esters of C10C20 fatty acids (FAs) and bistrimethylsilyl derivatives of C8C16 ω‐hydroxy fatty acids (HOF As) were determined by integration of total ion chromatograms obtained using a conventional gas chromatograph‐mass spectrometer in the electron impact ionization mode. For the alkanes up to C22 and for the FA‐TMS derivatives up to C18 (C21 including the TMS carbons), response factors increased linearly with total number of carbons (r2 > 0.99). The slope of this correlation (response factor = 0.0775n − 0.338, where n is the total number of carbon atoms in each analyte) is essentially identical with those determined in earlier studies for smaller molecules not containing silicon. For the HOFA derivatives up to C14 (C20 including TMS carbons), the molar response factors also increased linearly with total number of carbons, but for reasons not yet apparent the regression line for these homologs was different (response factor = 0.0330n + 0.456; r2 > 0.99). Response factors for higher homologs in all three series fell below the regression line for the lower homologs, the deviation increasing with increasing molecular mass and increasing GC retention time. In all three series the upper limit to the linear portion of the correlation corresponded to the homolog whose GC retention time was ca 15 min under the conditions used; a high injection port temperature was found to be the most critical factor in extending the linear range of the correlation.

Stereospecific polymerization of higher α‐olefins with the solvay type catalyst TiCl3/Cp2Ti(CH3)2

AbstractPolymerizations of higher α‐olefins (C10–C20) were carried out at 40°C in heptane, using the following three catalysts which differ in the isospecificity for propene polymerization: Solvay type TiCl3/Cp2TiMe2((A) highly isospecific), Solvay type TiCl3/AlEt3((B) isospecific) and TiCl3.3Py/MgCl2/AlEt3((C) aspecific). The isospecificity of the catalysts was found to decrease in the following order: (A) ≫ (B) ≫ (C), which agrees well with the results obtained in propene polymerization. The crystallinity of these polymers is discussed in brief.

Production of detergent‐grade trisodium citrate

AbstractAn efficient process to produce a technical‐grade trisodium citrate suitable for detergent use has been demonstrated. Ammonium citrate is produced as an intermediate by a continuous fermentation approach usingCandiada lipolytica yeast and C10–C20 linear paraffin. After removing yeast cells and residual oil by centrifuge, ammonia is distilled off with addition of sodium hydroxide. Trisodium citrate is recovered by methanol precipitation. Impurities, e.g., isocitrate, coloring materials and odorous substances dissolve in methanol and are removed. The methanol is recovered and recycled. A simple approach to convert the trisodium citrate solution directly to a solid for possible use in detergents failed because of the objectionable color, odor and high hygroscopicity.

Relationship between low- and high-molecular-weight acids in complex calcium greases based on soaps of synthetic fatty acids

1. The properties of cCa greases based on both narrow and especially wide SFA fractions depend less on the molar ratio of the low- and high-molecular weight acids than for cCa greases based on soaps of individual carboxylic acids. The optimum molar ratio of HAc to the narrow SFA fractions is approximately 2∶1 while for wide C10–C20 SFA fractions it is 1.5∶ 1, which is lower than for individual carboxylic acids (3∶1). 2. A cCa soap of SFA fractions has a reduced thickening effect compared with the soaps of individual carboxylic acids. They surpass the greases thickened with the cCa soap of individual carboxylic acids in a number of properties (viscosity-temperature behavior, colloidal stability). Both wide and narrow SFA fractions are promising raw materials for preparing cCa greases.

Microbial transformation of hydrocarbons. II. Growth constants and cell composition of microbial cells derived from n-alkanes.

AbstractCultivation of Norcardia sp., Mycobacterium phlei, and Candida lipolytica in inorganic salt solution containing n‐alkanes C10–C20 as solo carbon and energy source was investigated. Generation times of 0.5–7.0 hr were typical during the exponential growth phase. The final cell concentrations (dry weight) were usually 9–26 g/l with n‐alkane mixtures ranging from n‐decane through n‐eicosane. A linear dependence was found between the production of cell mass and the consumption of n‐alkanes. The rest concentration of n‐alkanes in the cell mass is in all experiments smaller than 0.5% (w/w). Cell yields were Ysub 60–142% and for Ye 50–97% based on n‐alkane utilization. In one case, with the Nocardia NBZ 23, the substrate specifity on hydrocarbons and on a n‐alkane mixture C10‐C20 was studied. The cell mass recovered from the fermentations contained 47.8–57.7% carbon, 5.6–9.95% nitrogen, 7.2–9.4% hydrogen, 35–62% crude protein, and 6–36% lipid. Cellular protein and lipid synthesized by an organism is influenced by the type of nitrogen source. The amino acid, glucosamine, muramic acid, 2,6‐diaminopimelinic acid, and fatty acid distribution in organisms grown on n‐alkanes compared with a corresponding fermentation on glucose as sole carbon source were also estimated.

New developments in synthetic fatty acids

AbstractNew developments in synthetic fatty acids have occurred in the last few years in Russia, Japan, the United States and Canada. In 1959 Russia decided to replace 40% of natural fatty acids in soaps with synthetic fatty acids. In 1966, 548 million pounds of C5–C30 synthetic fatty acids were produced including 288 million pounds of C10–C20 fatty acids. Forty million pounds of fatty acids are converted directly to the fatty alcohols for detergent use. A conservative estimate predicts that one billion pounds of synthetic fatty acids will be produced in Russia by the end of the current five‐year program. Reports say that the Japanese have been interested in the oxidation of not only paraffin hydrocarbons but naphthenic petroleum hydrocarbons as well. Production of lower homology fatty acids up to butyric acid is being seriously considered in Japan. In America the most likely syntheses aside from “oxo” syntheses being considered for the manufacture of products like lauric acid is the carboxylation of the Ziegler intermediates prepared from ethylene polymerization. Some data on the current and future coconut oil consumption by major end‐use for Canada and the United States are presented. Synthetic lauric acid is predicted for 1970 in the United States.

The effects of a potassium-manganese catalyst on the acceleration of wax oxidation by atmospheric oxygen

1. A study has been made of the kinetics of hydrocarbon consumption, the formation of neutral oxygenated compounds (ketones, alcohols, and fatty acids) in the liquid-phase oxidation of wax by atmospheric oxygen containing different amounts of potassium-manganese catalyst. It is concluded that a K-Mn catalyst retards some oxidation stages and accelerates others. In particular, during the over-all retarding action of the potassium salts of fatty acids present in K-Mn catalyst, manganese salts accelerate the oxidation of ketones and alcohols. 2. The effect of catalyst composition on the yield and composition of the fatty acids has been studied, using 0.1% Mn alkaline manganese dioxide containing 0.025% K and 0.08% Mn + 0.005% K at 120–105°C and no catalyst at all at 125°C. With a decrease in the amount of catalyst and when it is completely absent, the quality of the oxidate is worse (the content of oxy-acids and keto-acids being increased). The yield of C10–C20 acids on the wax processed decreases from 53.5 to 40.5%. The yield of still acids to mixed acids is increased from 11.1 to 35.1%. The quality of the acids becomes poorer with a reduced amount of catalyst (the contents of keto-acids and unsaturated acids are increased, the color is intensified, and the color becomes worse).

Hydrolysis of Secondary Alcohol Sulphate by a Bacterial Enzyme

ROY'S speculation1 that alkyl sulphatases exist has been substantiated by our demonstration in a species of Pseudomonas, which we have designated C12B (ref. 2), of a primary alcohol sulphatase3 inactive with either aryl or secondary alcohol sulphatases. We have now isolated from soil enriched with a mixture of C10–C20 secondary alcohol sulphates (Oronite Division, California Chemical Co., San Francisco) a bacterium, tentatively identified as Aerobacter cloacae, which hydrolyses pentan-3ol sulphate. Cell free activity has been demonstrated.

A Simple Chromatographic Method for the Determination of the C10–C20 Saturated Straight-Chain Fatty Acids

IN 1951, we described a semimicro chromatographic method for the separation and determination of the C4–C10 volatile fatty acids1. In that publication a description was given of the preparation of a silica gel which proved to be highly suitable for this separation. In that method, which is based on the principle of Ramsey and Patterson2, the fatty acids up to C10 are separated on a column of silicic acid, using methanol as the immobile solvent, isooctane as the mobile solvent and bromcresol green as the indicator. Since this method is quick and simple and never fails to give excellent results, we have tried to work out an identical method for the determination of the higher saturated fatty acids C10–C20.