Alkaline Reagents Research Articles

Sodium hydroxide-assisted desulphurization of petroleum fluid coke

Desulphurization of a fluid coke produced commercially from a conventional petroleum crude oil was attempted. Direct hydrodesulphurization of the coke at 700°C resulted in ≈31 wt% sulphur removal; however, impregnation of the fluid coke with trace amounts of sodium hydroxide and subsequent hydrodesulphurization resulted in > 80 wt% sulphur removal primarily as H 2S. A significant part of the alkaline reagent could be recovered by hot water leaching of the desulphurized coke. The calorific value of the desulphurized coke is slightly lower than that of the starting material. The mechanism appears to be complex as the change in surface area was negligible upon impregnation and hydrodesulphurization. Economic evaluation of the desulphurization process, carried out at the Alberta Research Council, indicates that it has significant economic advantages over fluidized-bed combustion of the coke with limestone or combustion of the coke with flue gas desulphurization.

Total calcium and magnesium determined in serum with an automated stopped-flow analyzer.

We describe the measurement of total calcium and magnesium in serum with an automated microcomputer-controlled stopped-flow analyzer. The calcium method is based on the cresolphthalein complexone procedure, with 2-amino-3-methyl-1-propanol as the alkalinizing agent. The assay, performed on 60-fold prediluted samples, requires 50 microL of serum. Absorbance is measured at 580 nm for 1 s, after a 5-s delay. Response is linearly related to concentration up to 5 mmol/L; analytical recovery averaged 97.8%. Within-day CVs were 0.7 to 1.5%, day-to-day CVs 1.8 to 2.5%. Results compared well with those by continuous-flow Technicon SMA II method. A sample throughput of as many as 260 samples per hour is possible. The magnesium determination, a complexometric procedure, involves magnesium/calmagite complex in an alkaline reagent mixture and ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid to eliminate calcium interference. Prediluted serum samples are used (100 microL of serum diluted 25-fold), and absorbance at 520 nm is linear with concentration to 50 mg/L. Within-run CVs were 0.5 to 1.1%, and day-to-day 1.3 to 3.8%; analytical recovery was 99.3%. Results compared well with those by atomic absorption spectrometry (r = 0.994). A delay time of 10 and a measurement time of 2.5 s allows for a throughput of as many as 180 samples per hour.

Some factors influencing the effect of alkali treatment on crop residues

SUMMARYFive agricultural by-products, maize stover and cobs, wheat straw, grape marc and sunflower husks, were treated with alkaline reagents under various conditions.Maize stover and wheat straw reacted quickly with both sodium hydroxide applied at a level of 4 g NaOH/100 g dry residue and a mixture of calcium and sodium hydroxides (1:1), which led to changes in chemical composition and increases in digestibility. However, ensilage of the treated product at about 37% dry matter (D.M.) was not successful.When dried grape marc was treated with sodium hydroxide (4·3 g NaOH/100 g dry residue) apparent lignin content increased, although other changes in composition and digestibility were similar to the above. Nevertheless, digestibility remained low. Moreover, when previously ground marc was treated in the same way lignin and cellulose fractions increased markedly while digestibility decreased.Treatment of maize cobs with increasing amounts of sodium hydroxide (2·1–4·2 g/100 g dry residue) at 80% D.M. gave progressively more favourable results, although no improvement in digestibility was noted when half the sodium hydroxide was replaced by calcium hydroxide. Similar positive results were obtained under industrial conditions at application rates of 3·2 and 4·5 g sodium hydroxide per 100 g dry residue. Pelleting the product led to a further increase in digestibility.Sunflower husks also showed a decrease in hemicellulose content and increases in digestibility and volatile acid content after treatment with 4·4 g NaOH/100 g dry residvie under industrial conditions. Lignin content was unchanged. The pelleted products (about 80% D.M.) were stable for more than 6 months when stored in paper sacks.Except with grape marc loss of hemicellulose provided a general indication of the success of alkali treatment, although correlation with increased digestibility did not reach statistical significance (r = 0·34). Volatile acid production and alterations in lignin content were not suitable as general indicators.In general, alkali treatment of the examined materials improved digestibility, although the products with a high water content were subject to undesirable fermentative changes during storage and therefore should be used within a few days.

Upgrading of delayed and fluid cokes from oil sand by desulfurization

AbstractCalcination of delayed and fluid oil sand cokes with alkaline reagents at high sodium/sulfur ratios followed by leaching gave almost complete desulfurization in terms of gaseous combustion products. Use of smaller proportions of alkaline reagents with hydrodesulfurization at 650 to 850°C also resulted in extensive removal of sulfur as hydrogen sulfide.

Preparation of surfactants by condensation of fatty acid esters with hydrolyzed proteins

AbstractProducts with good surface‐active properties can be easily prepared by condensation of fatty‐acid methyl esters with polypeptides derived from collagen proteins by hydrolysis. The condensation is done at moderate reaction temperatures (ca. 155 C) in dimethylsulfoxide solvent, and is promoted by sodium hydroxide or other alkaline reagents. The method works best with unsaturated esters, such as methyl oleate, which are more soluble in the reaction mixture, and which yield more soluble products, but also works well with the mixture of saturated and unsaturated fatty acid esters in methyl tallowate. The reaction appears to be a transamidation reaction in which incorporation of the fatty acid moiety results in partial cleavage of the polypeptide chain and in formation of methyl alcohol. Other solvents which can dissolve both fatty acid esters and collagen‐derived proteins, such as ethylene glycol, can be used to advantage in this reaction.

A study of the stability of conjugates of N‐benzoyl‐N‐(3‐chloro‐4‐fluorophenyl)‐DL‐ alanine during extraction from Avena sativa

AbstractExtensive metabolism occurred within 24 h of treatment during studies of N‐benzoyl N‐(3‐chloro‐4‐fluorophenyl)‐DL‐alanine (I) in oats. However, marked differences were observed in the apparent pattern of metabolism when different methods of extraction were used. Two major groups of metabolites were found (based on chromatographic behaviour), the first containing mainly the glucose ester of I, and the second containing other sugar conjugates of I. These groups of metabolites and the residual I could be extracted from plants with either aqueous acetone or boiling ethanol to give the same quantitative distribution of metabolites. However, if 80% ethanol was used as extraction solvent, and sodium hydrogen carbonate was used as a leaf wash prior to extraction, dramatic decreases were observed in the concentration of conjugates formed, and large quantities of the ethyl ester of I were also formed. It is concluded that the common experimental practice of using sodium hydrogen carbonate or other alkaline reagents for washing residual herbicides from treated leaves should be avoided, particularly in studies with acidic herbicides.

REMOVAL OF TANNINS AND IMPROVEMENT OF IN VITRO PROTEIN DIGESTIBILITY OF SORGHUM SEEDS BY SOAKING IN ALKALI

ABSTRACTSoaking of sorghum seeds at 30° C in 0.05M sodium hydroxide and potassium hydroxide removed 75–85% of the tannins in 24 hr. Treatment at 100°C increased the rate of extraction and reduced the time required to leach 75–85% tannins from 24 hr to 20 min. Under similar conditions, 0.05M sodium carbonate removed 77% whereas soaking in distilled water removed only 30%. Dry matter loss due to the treatments with alkaline reagents ranged from 1.2–2.3%. Extraction of tannins in 0.05M alkaline solution at 100° C for 20 min improved in vitro protein digestibility of high tannin seeds 2˜5 fold as compared to untreated seeds.

Desulphurization of a fluid coke similar to the Athabasca oil sands coke

Almost complete desulphurization of a high-sulphur fluid coke was achieved by impregnating the coke with suitable alkaline reagents followed by high-temperature calcination in an inert atmosphere and subsequent leaching of the coke to remove soluble metal sulphides formed during calcination. Sodium hydroxide and sodium carbonate were found to be the most effective bases. Sodium sulphide was detected in the calcined, non-leached coke by X-ray diffraction. Methane, carbon monoxide, carbon dioxide, ammonia and water, in addition to hydrogen sulphide, were detected in the gaseous product stream by gas chromatography. Flow rate of the inert gas and the particle size of the coke employed in this investigation had no effect on the extent of desulphurization. A maximum desulphurization was observed at a calcination temperature of 850 °C.

Change in the electric double-layer capacitance of magnetite in sodium hydroxide solutions

1. Measurements of the differential capacitance of monocrystalline natural magnetite in sodium hydroxide solutions by the impedance method have shown that the measured capacitance on magnetite markedly depends on the sodium hydroxide concentration. This indicates significant electrochemical conversions of magnetite in these solutions. 2. Hysteresis of the current density and impedance components is observed during polarization; this is probably due to formation of a passive layer on magnetite during anodic polarization. 3. The potential of the differential capacitance minimum of magnetite is between +0.4 and +0.5 V with respect to a saturated calomel half-cell and is shifted somewhat toward the anodic region on decrease in the sodium hydroxide concentration. 4. The impedance measurement method can be used to investigate the state of the mineral surface after its treatment with alkaline reagents for subsequent investigation of the mechanism of flotation and other magnetite reprocessing operations.

Electric Utility Applications Of Fabric Filters

Encouraged by the successes attained with fly ash control by fabric filters in Pennsylvania Power & Light and Colorado Ute, other utilities are installing, planning, and/or considering baghouses as a practical and economical means for controlling emissions from the burning of low sulfur coals. Where deposits of alkaline reagents (i.e. nahcolite) are available, some power plants are also considering a process for dry scrubbing SO2 from the flue gas. By introducing such reagents with the emission ahead of the fabric collector, both partlculates and SO2 are removed.

Properties and Quantitative Estimation of Poorly Crystalline Components in Sesquioxidic Soil Clays

AbstractSesquioxidic soil clays from Oxisols in South Africa, Australia and Brazil, and two clays from Andosols in Japan and New Zealand, were investigated by selective dissolution techniques. Acid ammonium oxalate (pH 3) was found to be superior to currently popular alkaline reagents for extracting amorphous aluminosilicates and alumina from these clays. Boiling 0.5 N NaOH dissolved large amounts of finely-divided kaolinite and halloysite, while hot 5% Na2CO3 reaction was too slow (partial dissolution of synthetic amorphous aluminosilicates with one extraction) and insufficiently selective (gibbsite and kaolin of poor crystallinity dissolve to a variable extent). On the other hand, synthetic gels (molar SiO2/Al2O3 ranging from 0.91 to 2.55) dissolved completely after 2 hr shaking in the dark with 0.2 M acid ammonium oxalate (0.2 ml/mg). Specificity of oxalate for natural allophane was indicated by removal of similar quantities of silica and alumina using different clay:solution ratios. Oxalate extraction data indicated that allophane is absent in Oxisol clays. Allophane was determined quantitatively in volcanic-ash soil clays by allocating hydroxyl water content to oxalate-soluble silica plus alumina on the basis of an ignition weight loss-chemical composition function for synthetic amorphous alumino-silicates. Parameters of chemical reactivity and distribution of electric charges following various chemical pretreatments of allophane were found to correspond closely to those predicted on the basis of synthetic gel behaviour. Results for Oxisol clays suggested that the role of amorphous (oxalate-soluble) alumina in governing physicochemical properties is generally less than that of the poorly-crystalline, Al-substituted iron oxide component which is removed by deferration with citrate-dithionite-bicarbonate reagent.

Measurement of serum magnesium with a centrifugal analyzer.

We show how serum magnesium can be determined with a centrifugal analyzer. The method is based upon a manual procedure involving magnesium/calmagite complex formation in an alkaline reagent mixture. The assay, performed at 30 degrees C, requires 5 mul of serum in a final reaction volume of 405 mul, including 350 mul of reagent mixture. The stable color produced at 1 min is measured at 520 nm. Linearity studies showed that Beer's law was followed to 50 mg/liter. Average analytical recovery was 97.3%. Within-day studies showed CV's of 3.36% and 1.09%, compared to day-to-day variations of 5.32% and 3.04% at 18.8 and 46.6 mg of magnesium per liter, respectively. Correlation studies with the manual method, the Du Pont aca (methylthymol blue compleximetric) procedure, and atomic absorption spectroscopy showed correlation coefficients of 0.996, 0.976, and 0.950, respectively. Results compare excellently with those by common present methods. The method is fast, economical, reliable, and applicable to small specimen volumes.

Humic acids from lignite. 1. Analytical characteristics and thermal degradation

Humic acids (HA) extracted from a lignite with two alkaline reagents have been studied. In contrast to humic acids extracted from soil HA, the lignite acids show no differences in their physical and chemical analyses with the exception of the total carbonyl content. After acid hydrolysis the analytical characteristics do not change, but their behaviour on Sephadex indicates a molecular condensation. The parent material has similar characteristics to those reported in the literature and also shows no analytical differences after acid hydrolysis, but a number of i.r. absorption bands, due to kaolinite, the only clay mineral present, disappear after this treatment. By pyrolysis/gas chromatography both the lignite and the humic acids produce several low-b.p. compounds, the same in the three cases but in different amounts. By methylation it has been proved that a great part of such compounds are produced by radical reactions. Some, which do not increase on methylation, may indicate the presence of some longer chains in lignites.

Factors Affecting the Analysis of Illicit Lysergic Acid Diethylamide (LSD) Preparations

The use of organic solvents for the extraction and spectrophotometric estimation of LSD in illicit preparations is described. The E 1 c m 1 % values of LSD in eighteen organic solvents were determined. They range from 285 (n-propanol) to 435 (carbon tetrachloride) relative to a value of 280 for LSD in water. Use of an organic solvent therefore increases the sensitivity of the spectrophotometric estimation of LSD by up to 55%, and so l–2μg of LSD may be quantitatively determined using conventional instrumentation. The use of non-aqueous solvents did not enhance the resolution of the LSD spectrum. Direct extraction of LSD using an organic solvent was found to be more efficient than processes involving liquid/liquid extraction. The losses of LSD that occur during liquid/ liquid extractions and back-extractions were found to be high, particularly where back-extraction from chloroform to hydrochloric acid was carried out. The losses of LSD due to acid or alkaline reagents, illumination and high temperatures were briefly investigated and found to be small under the conditions likely to be employed in routine analysis. The recovery of LSD after thin-layer chromatography was found to be high.

Coloring of Urine by Phenothiazine Derivatives

Patients treated with Protizinic acid, one of the phenothiazine derivatives, found that their urine turned blue when it was mixed with tap water and reported this to the doctors, being worried about the unexpected phenomena. The refore the cause of this phenomena was examined.The color reaction of such phenothiazines as Chlorpromazine HC1 (Cp), Dimetotiazine (Dm), Protizinic acid (Pt), Promethazine HCl (Pm) and Metiazinicacid (Mt) to alkaline and acid reagents, purified water and tap water was examined. The pH of discoloring point was also determined by adding NaOH to test solutions which had been previously colored by HClO4. It was found that Pt and Mt solutions turned blue when mixed with tap water but had no color change when mixed with purified water. This color change was especially marked with Pt. The color substance in the Pt-HClO4 solution was not extractable by ether.The difference between tap water and purified water in the color reaction may be attributable to residual content of chlorine and iron ions in the tap water.

The purification time as a factor in the degree of desulphurization of continuous-spun viscose rayon

In continuous spinning the sulphur is normally eliminated from the viscose rayon without the help of alkaline reagents~ i.e. by washing the single yarn in hot softened water. Other methods of physical desulphurization take the form of treatments with dilute acids, solutions of neutral salts, and alcohols. One method, for example~ consists of desulphurizing the as-spun filaments with sulphuric acid solutions of a concentration of 80 170 g/litre and a minimal content in impurities (elementary sulphur~ salts of heavy metals~ etc.) /1/.

Detection of esters as hydroxamates after separation by paper electrophoresis

Paper electrophoresis lends itself to the study of several classes of compound containing a carboxylic ester function. These compounds can be located on pherograms after reaction with alkaline hydroxylamine, the resulting hydroxamates being revealed as coloured ferric iron complexes using a ferric chloride spray reagent. Wide variation is evident in the response of esters to the hydroxylamine reagent, and the differences in reactivity could be diagnostically useful. Although acetates and lactones react in mildly alkaline medium at room temperature, many esters such as acid phthalates, benzoates, and some tropane and pyrrolizidine alkaloids require a strongly alkaline reagent. Other pyrrolizidien alkaloids and many esters of o-sulphobenzoic acid require forcing conditions—elevated temperatures (up to 110°) in strongly alkaline medium—to form the corresponding hydroxamates. Some esters are not detectable using even more energetic conditions.

Pyrazines and their N-oxides

The N-oxides of 2- and 2,3-substituted pyrazines were synthesized. It was found that the synthesized 2-formylpyrazine N,N′-dioxide, in which the aldehyde group is in the hydrated form, undergoes redox transformations leading to deoxidation of one of the ring nitrogens and oxidation of the dihydroxymethyl group to a carboxyl group under the influence of alkaline reagents.

Transformations of 3,17‐Dioxo‐Δ4‐Androsten‐19‐al to estrane derivatives

Abstract3,17‐Dioxo‐Δ4‐androsten‐19‐al (II) is a suitable starting material for the preparation of estrane derivatives.Autoxidation gives the corresponding 10β‐hydroperoxide III, which can be converted to estrone (V) by reduction and aromatization.Treatment with alkaline reagents under various conditions can produce 3‐oxo‐Δ4‐ (VI), 3‐oxo‐Δ5(10) ‐ (VII) and 2‐hydroxymethylene‐3‐oxo‐Δ5(10) ‐ estrene (VIII) derivatives.

Studies on the Auxin Metabolism of Some Cereal Crops under Germination and Seedling Growth : II. IAA-oxidase inhibitors contained in wheat seedlings

The inhibitors of IAA-oxidase contained in dark-grown wheat seedlings are studied in this paper. Boiled water extract from dark-grown wheat seedlings showed an inhibiting effect on the IAA-oxidase activity when in higher concentration. It showed, however, a promoting effect when in lower concentration. Moreover, it showed a little interference with Salkowski's color reaction of IAA. The inhibitors were extracted from the fresh materials with methanol, n-butanol, iso-propanol, acetone, acetonitrile or ethylacetate with ease. But with benzene, n-hexane or petroleum ether, extraction was difficult. In order to identify the inhibitors, we have undertaken some experiments using paper chromatography and obtained the following results: these inhibitors showed positive color reactions with FeCl3 and diazo (alkaline) reagents, but negative with Al+++ and diazo (acid) reagents. As a result, it is suggested that these inhibitors are phenolics encluding flavonoids and catechins. From further studies using two-dimensional paper chromatography, it may be concluded that the IAA-oxidase inhibitors contained in dark-grown wheat seedlings are ferulic acid and other less active phenolcarboxylic acids.