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Water washing method

To separate the oil added an equal volume of fresh cool water (note waited until solution cooled before adding the water). The oil started to drop out perfectly, used DCM to extract all traces of the oil. This woik up is by far the cleanest, easiest and simplest to date... (This dreamer was tried all method of ketone synthesis)... Once the oil was extracted, the extracts were pooled washed with sodium bicarbonate lx, saturated solution of NaCI 1x, and two washes with fresh dHzO... Some time was required for the work up as there was a little emulsion from the use of the base wash and then with the first water wash. The JOC ref suggested using an alumina column to remove the catalyst (could be a better way to go). [Pg.81]

Niobic Acid. Niobic acid, Nb20 XH2O, includes all hydrated forms of niobium pentoxide, where the degree of hydration depends on the method of preparation, age, etc. It is a white insoluble precipitate formed by acid hydrolysis of niobates that are prepared by alkaH pyrosulfate, carbonate, or hydroxide fusion base hydrolysis of niobium fluoride solutions or aqueous hydrolysis of chlorides or bromides. When it is formed in the presence of tannin, a volurninous red complex forms. Freshly precipitated niobic acid usually is coUoidal and is peptized by water washing, thus it is difficult to free from traces of electrolyte. Its properties vary with age and reactivity is noticeably diminished on standing for even a few days. It is soluble in concentrated hydrochloric and sulfuric acids but is reprecipitated on dilution and boiling and can be complexed when it is freshly made with oxaHc or tartaric acid. It is soluble in hydrofluoric acid of any concentration. [Pg.28]

Water wash. This method is used to remove deposits. Distilled water is sprayed into the air inlet at a speeified rate and engine speed. This speed is normally at a redueed rpm so that the water will not flash into steam in the eompressor and therefore beeome ineffeetive on the latter stages or diffuser. [Pg.751]

The design of the economizer must be robust enough to survive occasional excursions beneath the acid dewpoint and the effects of the methods used to clean the economizer periodically. This may take the form of rapping equipment to shake off deposits, sootblowing by steam or air and water washing with lances. [Pg.386]

Traces of acid in the product almost always degrade product stability and in some cases can lead to self-ignition and expln. The usual methods of removing traces of spent acid is by washing with water and/or dil alkali solns followed by a water wash... [Pg.228]

Modern purification methods employ Na sulfite solns to react with the 0 and 7 -TNT isomers to form water soluble substances which can then be washed out of the desired a-TNT-However, these water washes form a blood-red soln — the bothersome red-water of TNT plants. Modern methods of disposing of red-water will be described in Section X... [Pg.239]

A commonly used procedure for the determination of phosphate in seawater and estuarine waters uses the formation of the molybdenum blue complex at 35-40 °C in an autoanalyser and spectrophotometric evaluation of the resulting colour. Unfortunately, when applied to seawater samples, depending on the chloride content of the sample, peak distortion or even negative peaks occur which make it impossible to obtain reliable phosphate values (Fig. 2.7). This effect can be overcome by the replacement of the distilled water-wash solution used in such methods by a solution of sodium chloride of an appropriate concentration related to the chloride concentration of the sample. The chloride content of the wash solution need not be exactly equal to that of the sample. For chloride contents in the sample up to 18 000 mg/1 (i.e., seawater),... [Pg.98]

Sodium Tantalales.—4 3 Sodium tantalate, 4Na20.8Ta206.25H20, is prepared by fusing tantalum pentoxide with caustic soda in a silver crucible excess of caustic soda is removed by washing with water, and the residue is crystallised from hot water. Another method consists in adding a concentrated solution of sodium chloride to the aqueous extract from a fused mixture of tantalum pentoxide and potassium carbonate, when the salt separates as a dense, micro-crystalline powder. It forms six-sided plates, a c=l 1-0167. It loses most of its water of crystallisation between 105° and 110° C., but the remainder (apparently five molecules) appears to be water of constitution, as its removal takes place only at much higher temperatures, with decom-... [Pg.201]

Pretreatment primers. In this method of use the silane may be applied from a solvent solution, by vapour phase deposition or by plasma deposition although solvent application is the more usual. The solution usually contains water and silane at a concentration of 1-2 wt%. The applied film may be water washed before subsequent coating/bonding and/or heat cured. The solvent(s) used may be important in both the stability of the solution and the performance, particularly in the wet adhesion. It has been shown that the presence of water either in the solution or as a final rinse is important, particularly in the case of AAMS and presumably other silanes [1]. Other factors which are important include the concentration of silane the pH of the solution the thickness of the silane film deposited. [Pg.24]

Viscosity poses a similar problem in the production of pulp wash concentrate. Pulp wash consists of juice solids obtained by countercurrent washing of pulp after its separation from juice. On a °Brix basis, pulp wash liquids are higher in pectin than juice from which the pulp has been screened (19). Concentration of pulp wash above 40°Brix is at times hampered by excessive pectin levels (20). To control viscosity processors may be forced to reduce finisher pressure to minimize pectin extraction, thereby curtailing yield. A more effective solution is to treat pulp wash with pectinases to reduce pectin levels (21). If pectinases are incorporated into the wash water, this method has the advantage of increasing total solids yield by reducing juice retention in the pulp. [Pg.112]

Miller, S.J. and Yuen, L.-T.(September 2007) Mixed matrix membrane with super water washed silica containing molecular sieves and methods for making and using the same. US Patent 7,268,094. [Pg.165]

In our own work, the effectiveness was examined of trace element removal by two chemical coal cleaning methods being studied for possible large-scale application. One method involved treatment with aqueous Na,C03 solutions, and the other involved treatment with molten NaOH/KOH mixtures. In each case, acid washes were used as subsequent cleaning steps to decrease the ash content, followed by water washes in the final step. Although the primary objective of these treatments was to remove sulfur and ash-forming minerals, the extraction of trace elements from these coals was examined as an additional benefit of chemical coal cleaning. [Pg.74]

Several chemical techniques have also been developed, such as simple oxidation using hydrogen peroxide or lead tetraacetate.77 Both these protocols suffer from harsh reaction conditions and additional toxicity issues. A more functional group-tolerant method is the use of tris(hydroxy-methyl)phosphine to coordinate the ruthenium.78 This complex is water soluble and can be washed from the product by several simple water washes. The main drawback to this method is the large excess of phosphine needed (25 mole equiv./mole of Ru).46... [Pg.555]

The chemical and oil refining industries employ a variety of methods to clear and clean storage tanks, pressure vessels, and pipelines as a preparation for maintenance or the actual maintenance itself. Depending on the job, water washing may not be suitable and the planners may use various acids and alkalis for this activity. There can be risks associated with such reactive chemicals, as noted in the following paragraphs. [Pg.86]

To use an ultrasonic cleaner, immerse the item to be cleaned in the cleaning solution within the device s tank. There are general-purpose and industrial-strength cleaning solutions as well as specific cleaning solutions for jewelry, oxides, and buffing compound removers. Turn the ultrasonic cleaner on for several minutes, and see if your item is clean. If not, repeat the process and/or try an alternate cleaning method. After an item has been cleaned, rinse as you would with a soap and water wash. [Pg.238]


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