Cent Hydrochloric Acid Research Articles

An Improved Acid for Calcium Sulfate-Bearing Formations

Abstract An improved acid for the treatment of sulfate-containing limestones and dolomites is described. The acid is designed to reduce the reprecipitation of dissolved calcium sulfate and the possibility of plugging permeable flow channels. In addition, this improved acid has a much lower reaction rate than that of regular acid; the advantages of a "retarded" acid are obtainable. Field testing of the acid has shown it suitable for use in sulfate-containing formations. Substantial improvements in productivity generally resulted. Introduction Acid treatments of limestones, dolomites and other formations bearing carbonate deposits are frequently unsuccessful when the calcareous formation contains sulfate, either as anhydrite (CaSO4) or gypsum (CaSO4 2H2O). Preliminary dissolution in acid followed by redeposition of calcium sulfate appears to be a major factor contributing to poor well performance after acidizing. The precipitate is usually the gypsum form of calcium sulfate, but in higher temperature formations it may be anhydrite. The freshly precipitated crystals are nearly always very small and needlelike. They may occupy a gross volume many times that of the original anhydrite crystals and will obviously constitute an impediment to flow through newly enlarged flow channels. It is believed that the redeposition problem is most severe when anhydrite lines the fracture systems and large pores which supply the effective permeability of a formation. Microscopic inclusions of calcium sulfate also present large sulfate surface areas for dissolution in acid. In either case, great amounts of calcium sulfate may dissolve before the acid can be spent on formation carbonates. For regular spent acid (originally 15 per cent hydrochloric acid) the precipitate could be as much as 270 lb gypsum/1000 gal acid. Two techniques have been applied by the industry for reducing sulfate plugging during acidizing. The method commonly employed in the field is the attempted removal of a quantity of regular treating acid before it has reacted completely with the formation. This is practiced because the solubility of calcium sulfate is greater in a solution that is still acidic than in one which has been largely spent on the formation rock. The chance of precipitative plugging is therefore reduced if the withdrawal is successful. However, it is often impossible to get the acid out of the formation before precipitation occurs.

Using Heat in Combination With Solvents To Clean Up Formation Flow Channels

Abstract A new stimulation technique has been developed for restoring blocked permeability in both injection and production wells. The method utilizes a combination of heat and chemical solvents to remove organic and inorganic deposits that have accumulated in formation flow channels and on the face of the wellbore, during operation. The treatment is conducted in two-stages. First, a gelled oil, carrying a suspension of 20–60 mesh magnesium pellets, is injected into the pay zone. This is followed by 15 per cent hydrochloric acid which, reacting with the magnesium pellets already in the well, liberates considerable heat (8,400 BTU/lb of magnesium). As a result, the temperature of the formation may be raised several hundred degrees. The spent acid is now produced from the well, followed by the oil which has picked up many paraffin and asphalt deposits liquefied by the liberated heat. In addition, the acid solution used to release the heat reacts with any lime, oxide or sulfide deposits on the face of the pay, dissolving and removing them. To date, this new heat application has been successful on about 60 per cent of production and injection wells treated. Many of these wells have failed to respond to other type treatments. As refinements and improvements are made in treating procedures and selection of wells for treatment, a higher success ratio may be expected. Introduction Many wells show good output after initial stimulation treatments, but after a short time production falls off more rapidly than would be expected on the basis of formation pressure and permeability. The cause for such abnormal declines is usually either an equipment failure or change in formation characteristics. In the latter case, the trouble is frequently caused by some foreign material which partially plugs the flow channels, hindering the migration of reservoir fluids into the wellbore. Such plugging may result from either organic or inorganic mineral deposits, or both. The buildup of organic deposits often results from a decline in reservoir pressure which allows dissolved gas to break free.

Metallographic Studies of Iron Carbide and Tungsten Carbide

IN most metallographic investigations of steels or of cemented carbides the fine details of the carbides are not studied. We have just completed an etching study of iron carbides made in three different ways and of some tungsten carbide (1/32-in. equilateral triangles) single crystals. The iron carbide studies, made with Carapella's reagent (5 gm. ferric chloride, 2 ml. concentrated hydrochloric acid and 99 ml. methyl alcohol) etching for 20–60 min., revealed cracking as the principal deformation mechanism and twinning as the secondary agency. The cracking behaviour has been described previously, but the twinning appears to be a new observation1. In two cases only, out of hundreds of samples studied, the cracks found were aligned along the twinning planes in the carbides. These observations were made upon a carburized plain carbon steel, upon a carburized ‘Westinghouse Puron’ iron (spectrographically pure) and upon a pure, massive, polycrystalline, iron-manganese carbide kindly supplied by Dr. L. S. Darken of U.S. Steel Research from his recent ternary system studies. In the two carburized samples there was no possibility of mechanical work having caused cracking of the carbide. Fused caustic, 50 per cent nitric acid and 50 per cent hydrochloric acid were also successful etching reagents.

弗素化合物の歯牙硬組織に対する作用の組織化学的研究

The author made transverse ground specimens of the teeth which had been treated by fluorine, and the attitudes of the fluorine ion were studied histo-chemically.I) Experimental study on the penetration of fluor ion into the enamel.Ground sections were made from the human and dog's teeth, which had been immersed in 2 per cent solution of fluoride, and histo-chemical investigation on the penetration of fluorine into the enamel was made by means of Bohmer's hematoxylin staining.As the results the non-stainable area was observed.1. Fluor ion penetrated through the organic matter of enamel cuticle, enamel lamelle, rod sheath or cracks.2. The width of non-stainable area showed a tendency of direct proportion with the duration of staining, but inverse proportion with the increase of age of the specimens.3. There is the appearance of non-stainable area on the surface of the enamel by application of various fluoride solutions (NaF, NaHF2, Na2SiF6, NH4F), but no appearance of difference in the degree of penetration.4, Penetrated fluor ions were not dissolved out from the enamel, namely these ions were fixed in the enamel.5. At the surface enamel of dog teeth, the non-stainable area could be observed in vivo as well as at that of human enamel.6. The diluted Bohmer's hematoxylin was discoloured in the test tube by the presence of more than 9 ppm of fluor ion.II) Acid-resistance of the enamel through which the fluor ion are penetrated.The transverse ground specimens of teeth which had been immersed in the fluorine solution were put on the Petri dish and acid was pored on them. These specimens were examined histologically. The acid-resistance in these specimens could be assured.1. The surface, lamelle, caries, and crack of the enamel which were penetreted by fluor ion were clealy distinguished from these of the enamel, namely, by difference of decalcification.2. At one minute after the specimens were immersed in 5 per cent hydrochloric acid solution, the area penetrated by fluor ion was regarded as a dark part. On the other hand, at thirty' minutes after the specimen were immersed in 5 per cent lactic acid solution, the area was light.

Absorptiometric Microdetermination of Total Sulfur in Rubber Products

Abstract The 1.0 to 2.5 per cent of sulfur normally present in rubber products is oxidized with concentrated nitric acid-bromine reagent, followed by perchloric acid in the presence of excess lead nitrate. Sulfur as lead sulfate is precipitated and washed with acetone. The lead sulfate is dissolved in 50 per cent hydrochloric acid, and absorbance of the lead chloride complex is recorded at 270 mµ. Sulfur is calculated on the basis of the measured lead content of the precipitate. The high sensitivity puts the method in the micro-range. An experienced analyst can analyze 40 to 50 samples a day. Precision and accuracy are comparable to those of the conventional barium sulfate gravimetric method at the low sulfur concentrations normally found in rubber products.

Resolution by means of a Micro-organism of Racemic Diaminosuccinic Acid and Determination of its Configuration

THE chemical structure of diaminosuccinic acid is analogous to aspartic acid, asparagine, C4-dicarboxylic acids and the other biologically important substances. The acid, however, has not yet been found in Nature, and so has never been fully investigated. In 1925, racemic acid was resolved into its antipodes by Kuhn1, through the morphine salt of N,N′-dibenzoyl diaminosuccinic acid; [α]20 D = − 18.9° (10 per cent hydrochloric acid). Suzuki and Suzuki2 found, during the course of an investigation on the behaviour of micro-organisms towards the acid, that Micrococcus ureae was capable of growing on a medium containing the racemic acid as the sole source of nitrogen, and that about half the amount of racemic acid always remained even after full growth. From these observations the authors considered that the micro-organism preferentially assimilated one of the two optical isomers, and that a non-utilizable antipode could perhaps be isolated from the medium.

Anti-acetylcholine and anti-histamine actions of the total alkaloids of Rauwolfia serpentina benth.

Dasgupta, Ray, Roy and Werner1, Mukherjee2 and the present authors3 have made certain observations on the anti-adrenaline effect of extracts of Rauwolfia serpentina, but their effects on the action of acetyl-choline or of histamine have not yet been reported. Experiments have been carried out on isolated strips of guinea pig ileum in Dale's bath, containing oxygenated Ringer–Locke's solution at 35° C., and the modifications caused by varying concentrations (10−6 to 10−4 gm./ml.) of extracts of Rauwolfia serpentina (total alkaloids extracted in 2 per cent hydrochloric acid) on the action of acetylcholine (10−8 gm./ml.) or of histamine (10−8 to 10−7 gm./ml.) were studied. The extracts produced, by themselves, a definite but slight and transient contraction of the intestine. Dasgupta et al. 1 did not, however, find any stimulating effect on intestine in situ, whereas Chopra, Gupta and Mukherjee4 mention a stimulating property of the extract on such a preparation. (Dr. R. P. Banerjee, of the Indian Council for Medical Research, prepared extracts of Rauwolfia serpentina in three different concentrations of hydrochloric acid (namely, 2, 5 and 10 per cent) with the view of fractionating the different active principles. The results obtained with an extract in 2 per cent hydrochloric acid are described here; those with 5 and 10 per cent acid extracts are under investigation.)

Absorptiometric Microdetermination of Total Sulfur in Rubber Products

Abstract The 1.0 to 2.5 per cent of sulfur normally present in rubber products is oxidized with concentrated nitric acid-bromine reagent, followed by perchloric acid in the presence of excess lead nitrate. Sulfur as lead sulfate is precipitated and washed with acetone. The lead sulfate is dissolved in 50 per cent hydrochloric acid, and absorbance of the lead chloride complex is recorded at 270 mµ. Sulfur is calculated on the basis of the measured lead content of the precipitate. The high sensitivity puts the method in the micro-range. An experienced analyst can analyze 40 to 50 samples a day. Precision and accuracy are comparable to those of the conventional barium sulfate gravimetric method at the low sulfur concentrations normally found in rubber products.

工場廃水の浄化方法に関する研究-III

In order to estimate appropriate volume of the waste to be treated, determination has been made of the volume and concentration of the original waste liquor from the digester of 1.5 tons capacity for knot or chips and of the washing from diffuser. Based on a minimum concentration that brings about a dark coloration in Carassius auratus, it has roughly been estimated that 1.4 tons out of 3.1 tons of the original waste should be subject to the acid treatment, provided that about 1.3 tons of the original waste be used for conglomerating briquet. Approximate amount of hydrochloric acid needed for the treatment was calculated to be 24 liters of 38 per cent hydrochloric acid when 1.4 tons of waste liquor from one batch of digestion be reused for cooking the used paper and straw. It has been shown that precipitated poisonous ingredients of the waste could not be extracted with hot water and that the suspension of the precipitate gave as much harmfulness as the original waste. It follows, accordingly, that when the waste be discharged without filtration after the acid-treatment, the precipitate deposited over the drainage-basin would give some harmful effect on aquatic organisms.

Anthocyanins in Bananas

THE inflorescence of the banana bears female flowers at the base and male flowers apically. At each node is a cluster of flowers subtended by a brightly coloured bract, and it is upon the anthocyanins of these bracts that most of the results summarized below are based. The pigments were extracted in 1 per cent hydrochloric acid and examined in the test-tube and by paper chromatography. A picrate which was isolated from one species yielded glucose only on hydrolysis. Definition of the glycosidal types awaits determination of the sugar residues in other purified samples. After hydrolysis, the antho-cyanidins were determined by means of chromatography in the Forestal solvent1 and in butanol–2N hydrochloric acid2 used separately, or jointly for a two-way separation.

Identity of auxin in normal urine.

THE aim of this work was to obtain auxin a, first isolated by Kogl, Haagen-Smit and Erxleben1 from human urine in 1933. In their isolation procedure, these workers extracted a urine concentrate at an acid pH with ether. The ether extract in turn was partitioned into a neutral and an acid fraction with sodium bicarbonate. The auxin was present in the acid fraction and was subjected, in the final stages of the isolation procedure, to refluxing with methanol containing 1.5 per cent hydrochloric acid. This step was followed by high-vacuum distillation, yielding a crystalline material with high auxin activity which they called auxin a.

A biliviolin metal complex in ox bile.

AN ethyl acetate extract of fresh ox bile acidified to 5 per cent with concentrated hydrochloric acid yielded a dark green waxy solid on taking to dryness in vacuo. Chromatography of this substance from a 2 : 10 methanol–ether solution on a column consisting of a mixture of 12 gm. of acid-washed talc and 3 gm. ‘Hyflo’ filter-aid gave a single grey-green band which could be partly eluted with methanol. The absorption spectrum of the eluted substance (a green solid) in methanol and in methanolic hydrochloric acid is shown in the accompanying figure. Acidification changed the colour of the solution from green to violet and shifted the absorption maximum from 646 to 568 mμ A chloroform solution of the compound showed a strong red fluorescence in ultraviolet light. The pigment could not be extracted from chloroform solution with 1 per cent hydrochloric acid, demonstrating that it was biliviolin and not a bilipurpurin complex.

Anthocyanins in Bananas

THE inflorescence of the banana bears female flowers at the base and male flowers apically. At each node is a cluster of flowers subtended by a brightly coloured bract, and it is upon the anthocyanins of these bracts that most of the results summarized below are based. The pigments were extracted in 1 per cent hydrochloric acid and examined in the test-tube and by paper chromatography. A picrate which was isolated from one species yielded glucose only on hydrolysis. Definition of the glycosidal types awaits determination of the sugar residues in other purified samples. After hydrolysis, the antho-cyanidins were determined by means of chromatography in the Forestal solvent1 and in butanol–2N hydrochloric acid2 used separately, or jointly for a two-way separation.

Hydrolysis of 17-ketosteroid conjugates in urine.

Jensen and Totterman (1) claimed that the partial destruction and transformation of the β-17-ketosteroids, during hydrolysis of their conjugates by mineral acids, could be lessened by a two-stage ether extraction; firstly after an overnight boiling of non-acidified urine, and secondly after hydrolysis of the same material with mineral acid in the usual way. The results given by this technique have been compared with those given by a more usual hydrolysis in which the urine is boiled with 10 per cent hydrochloric acid for ten minutes and then extracted with ether. The results of hydrolysis of the 17-ketosteroid conjugates of five urines by the two methods are shown in Table 1 and do not confirm those of Jensen and Totterman. The reason for this discrepancy is not clear. The total 17-ketosteroid yield by their method was less than 60 per cent of that given by the method used in this laboratory.

Urinary porphyrins in experimental lead poisoning.

THE porphyrin excreted in the urine of normal and of experimentally lead-poisoned rabbits has long been regarded as coproporphyrin. The recent development1 of a chromatographic method for the separation of porphyrins according to the number of carboxyl functions has already revealed 3- and 5-carboxyl porphyrins in a number of pathological urines. We have investigated the urinary ether-soluble porphyrins of rabbits which received loading doses of 13.7 mgm./kgm. of lead chloride intravenously, and were then fed on a diet containing 250 p.p.m. of lead carbonate for periods up to four months. Urine was collected over periods of three days and preserved with toluene. The porphyrins were extracted with ether and acetic acid by the technique previously used by one of us2, and estimated in 0.25 per cent hydrochloric acid with a Unicam spectrophotometer (λ = 401 mµ). They were chromatographed on paper at 7° C. by the method of Nicholas and Rimington1 to characterize the porphyrins present.

Paper Chromatography of Flax Fibre Polyuronide Hemicellulose

IT is well known that pectic substances are broken down during the retting of flax. There is evidence that other polyuronides also occur in flax straw and are attacked in retting1. Their constitution is therefore of great interest in flax research. The sugar constituents of the polyuronide hemicellulose have been investigated. This substance was obtained from fibre separated from flax straw by purely mechanical means without previous retting. Finely ground fibre was extracted successively with ether, petroleum ether, ethanol and water. Pectic substances were removed with seven 30-min. extractions with boiling 0.5 per cent ammonium oxalate solution. The residue, after washing with water, ethanol and ether followed by air-drying, was extracted twice for 24 hr. with cold 4 per cent sodium hydroxide solution. The filtered extract was acidified with glacial acetic acid and the hemicellulose was precipitated with ethanol. The precipitate was well washed and dried from ethanol and ether. Approximately 3 gm. of polyuronide hemicellulose was obtained as a slightly greyish powder, lignin content 1.8 per cent, uronic acid anhydride content 7.1 per cent (19 per cent hydrochloric acid method2).

塩化第一銅の塩酸溶液に対するニッケル及び銅合金の耐蝕性

The corrosion resistivities of Cu-base and Ni-base alloys against 20 per cent hydrochloric acid contaiuing 5 per cent of cuprous chloride at 70°C were investigated. Cu-Al alloys were rather better than Ni-Mo base alloys.

Bile Pigments from Normal Erythrocytes

Gardikas, Kench and Wilkinson1 have found that treatment of human erythrocytes with acetic acid in an oxygen-free atmosphere, in the absence of ascorbic acid, did not yield any biliverdin when the ether solution was extracted with 5 per cent hydrochloric acid. They claim that the bile pigments isolated by Lemberg and co-workers2,3 from human and sheep erythrocytes, and from horse oxyhaemoglobin, may have arisen as an artefact from choleglobin, the latter being formed from oxyhaemoglobin by the action of ascorbic acid ; ascorbic acid had been added in these experiments to prevent the oxidation of biliverdin to bilipurpurin. They have overlooked, however, that bile pigments had been obtained in an even somewhat higher yield without the addition of ascorbic acid, and also from horse carboxyhaemoglobin2. The yield is also unaltered if ascorbic acid is added together with the acetic acid, instead of being added immediately before acidification.

Microsynthesis of C14-Labelled Ethyl Iodide

CARBON dioxide labelled with C14 can be converted in good overall yield to ethyl iodide by way of acetylene and ethylene on the scale of about 10 micromoles. Acetylene can be produced from carbon dioxide1 in 90–95 per cent yield, and it may be reduced almost quantitatively to ethylene by the method of Traube2,3, in which it is shaken for an hour with a large excess of freshly prepared chromous chloride solution at room temperature. The chromous chloride solution is prepared by the rapid reduction of a solution of 1 part green chromic chloride hexahydrate in 2 parts 25 per cent hydrochloric acid with zinc wool, until the solution turns almost a copper sulphate blue. About 0·4 ml. of this solution is pipetted into a glass reaction vessel (see diagram), frozen in liquid nitrogen and evacuated. The acetylene is condensed into the tube which is then sealed off at A and allowed to warm to room temperature. After agitation for an hour, carried out by intermittent rotation about its axis of the reaction vessel held horizontally, the vessel is sealed on to the high vacuum apparatus at B and the break-seal opened. All the dissolved gas is boiled from the chromous chloride solution, and ethylene condensed at liquid nitrogen temperature into a trap connected with a McLeod gauge, water and any residual acetylene being held back in a U-tube at liquid oxygen temperature. The yield in terms of standard gas volume is 96-98 per cent in this stage, and the remaining few per cent of acetylene can be recovered from the oxygen-cooled trap.

Reaction of Nitrous Acid with Chlorophyll

Nitrous acid has been found to react readily with chlorophyll, giving four highly coloured crystalline compounds. The reaction was carried out as follows: 10 gm. of chlorophyll (commercial powder) was dissolved in 300 ml. of chloroform and 200 ml. of 3 per cent hydrochloric acid added; 12 gm. of sodium nitrite in 50 ml. of water was then added, with vigorous shaking, over a period of half a minute. The chloroform layer, which underwent a striking colour change from green to dark red, was separated immediately and washed with water. Evaporation of the solvent left a crystalline mass (10 gm.) from which the compounds A, B, C and D were obtained.