Subsequent Treatment

The cerium may now be removed from this solution by the bromate method (synthesis 14). Then the resulting solution is treated as before with excess oxalic acid or sodium suKate, the precipitates are again converted to hydrous oxides, and the latter are again dissolved in nitric acid. The rare earths from monazite are generally converted to double magnesium nitrates, 3Mg(N03)2-2(R.E.)-(N03)3 24H20 (synthesis 15), for preliminary fractionation. The rare earths from xenotime, after complete removal of cerium, may be converted to bromates (synthesis 17), and fractional crystallization of these salts may be commenced. 

Levy The Rare Earths, pp. 71, 79, Edward Arnold Co., London, 

Spencer The Metals of the Rare Earths, p. 18, Longmans, Green 

5HiO (dried at 110°) on the assumption of an atomic weight of 139 for the rare earth. Such a calculation will provide for sufficient excess of reagent. 

Inorganic Syntheses, Volume II Edited by W Conard Femelius 1946 by McGraw-Hill Book Company, Inc. 

---

In a subsequent treatment from the time-dependent response point of view, connection with the Greens function... 

I he methyl iodide is transferred quantitatively (by means of a stream of a carrier gas such as carbon dioxide) to an absorption vessel where it either reacts with alcoholic silver nitrate solution and is finally estimated gravimetrically as Agl, or it is absorbed in an acetic acid solution containing bromine. In the latter case, iodine monobromide is first formed, further oxidation yielding iodic acid, which on subsequent treatment with acid KI solution liberates iodine which is finally estimated with thiosulphate (c/. p. 501). The advantage of this latter method is that six times the original quantity of iodine is finally liberated. 

If much sodium bromide is present in the crude acetylmethylurea, this will not dissolve in the concentrated hydrochloric acid it dissolves, however, when the solution is diluted and has no effect upon the subsequent treatment with sodium nitrite. 

Later it turned out that activation of enamine components could not only be achieved by deprotonation of the nitrogen atom but also by connecting it with certain metals, e.g. Ni(II), Pd(II), or Co(II), and subsequent treatment with base. 

The benzylidene derivative above is used, if both hydroxyl groups on C-2 and C-3 are needed in synthesis. This r/vzns-2,3-diol can be converted to the sterically more hindered a-cpoxide by tosylation of both hydroxy groups and subsequent treatment with base (N.R. Williams, 1970 J.G. Buchanan, 1976). An oxide anion is formed and displaces the sulfonyloxy group by a rearside attack. The oxirane may then be re-opened with nucleophiles, e.g. methyl lithium, and the less hindered carbon atom will react selectively. In the following sequence starting with an a-glucoside only the 2-methyl-2-deoxyaltrose is obtained (S. Hanessian, 1977). 

An outstanding feature of the adsorption of water vapour on silica is its sensitivity to the course and subsequent treatment of the silica sample, in particular the temperature to which it has been heated. Figure 5.15 shows the strong dependence of the isotherm for a particular silica gel on the temperature of its heat treatment the isotherm is progressively lowered as the temperature increases, especially above 400°C, and the shape changes from Type II for the lower temperatures to Type III for 600°C, 800°C and 1000°C. 

Nonvolatile analytes must be chemically converted to a volatile derivative before analysis. For example, amino acids are not sufficiently volatile to analyze directly by gas chromatography. Reacting an amino acid with 1-butanol and acetyl chloride produces an esterfied amino acid. Subsequent treatment with trifluoroacetic acid gives the amino acid s volatile N-trifluoroacetyl- -butyl ester derivative. 

The enthalpy of the copolymerization of trioxane is such that bulk polymerization is feasible. For production, molten trioxane, initiator, and comonomer are fed to the reactor a chain-transfer agent is in eluded if desired. Polymerization proceeds in bulk with precipitation of polymer and the reactor must supply enough shearing to continually break up the polymer bed, reduce particle size, and provide good heat transfer. The mixing requirements for the bulk polymerization of trioxane have been reviewed (22). Raw copolymer is obtained as fine emmb or flake containing imbibed formaldehyde and trioxane which are substantially removed in subsequent treatments which may be combined with removal of unstable end groups. 

Boron trifluoride catalyst may be recovered by distillation, chemical reactions, or a combination of these methods. Ammonia or amines are frequently added to the spent catalyst to form stable coordination compounds that can be separated from the reaction products. Subsequent treatment with sulfuric acid releases boron trifluoride. An organic compound may be added that forms an adduct more stable than that formed by the desired product and boron trifluoride. In another procedure, a fluoride is added to the reaction products to precipitate the boron trifluoride which is then released by heating. Selective solvents may also be employed in recovery procedures (see Catalysts,regeneration). 

The central carbon atom is derived from an aromatic aldehyde or a substance capable of generating an aldehyde during the course of the condensation. Malachite green is prepared by heating benzaldehyde under reflux with a slight excess of dimethyl aniline in aqueous acid (Fig. 2). The reaction mass is made alkaline and the excess dimethylaniline is removed by steam distillation. The resulting leuco base is oxidized with freshly prepared lead dioxide to the carbinol base, and the lead is removed by precipitation as the sulfate. Subsequent treatment of the carbinol base with acid produces the dye, which can be isolated as the chloride, the oxalate [2437-29-8] or the zinc chloride double salt [79118-82-4]. 

The principal objectives of pretreatment are to remove heavy metals prior to subsequent treatment, to neutralize the wastewater to a suitable pH for discharge or subsequent treatment to remove high concentrations of suspended soflds, to eliminate or reduce toxicity, and to eliminate or reduce volatiles. The concentrations of various pollutants that make pretreatment desirable are summarized in Table 7. 

These appHcations require withdrawal of water from a source and subsequent treatment and conveyance to the point of use. Water is also used without being withdrawn from a source, eg, for navigation, recreation, wild and aquatic life propagation, hydroelectric-power generation, and waste assimilation and transport. The principal types of withdrawal uses and their average rates are given in Table 2. Some of these withdrawal rates represent multiple uses of the same water along main rivers in metropoHtan and industrialized areas. 

No tniodoarsorane has been reported. Triduorodiphenylarsorane [2357-18-8] C22H2QASF2, has been prepared by several methods. One method involves the reaction of benzene with arsenic pentafluoride and subsequent treatment of the resulting salt with cesium fluoride (147) ... 

Castor oil sulfation results largely in a sulfuric acid ester in which the hydroxyl group of ricinoleic acid has been esterified. However, other reactions can also take place. For example, the double bond can be attacked to produce an ester or the hydroxysulfonic acid (33). Hydrolysis of the sulfuric acid esters occurs during the reaction and subsequent treatment forming hydroxy acids and sulfuric acid. These hydroxy acids can be further sulfated. 

The traditional view of emulsion stability (1,2) was concerned with systems of two isotropic, Newtonian Hquids of which one is dispersed in the other in the form of spherical droplets. The stabilization of such a system was achieved by adsorbed amphiphiles, which modify interfacial properties and to some extent the colloidal forces across a thin Hquid film, after the hydrodynamic conditions of the latter had been taken into consideration. However, a large number of emulsions, in fact, contain more than two phases. The importance of the third phase was recognized early (3) and the lUPAC definition of an emulsion included a third phase (4). With this relation in mind, this article deals with two-phase emulsions as an introduction. These systems are useful in discussing the details of formation and destabilization, because of their relative simplicity. The subsequent treatment focuses on three-phase emulsions, outlining three special cases. The presence of the third phase is shown in order to monitor the properties of the emulsion in a significant manner. 

In a similar manner, phthalazine or its alkyl- or aryl-substituted derivatives are obtainable from 1,2-diacylarenes (Scheme 76). Phthalaldehydic acid and its analogs are transformed by hydrazines into the corresponding phthalazin-l(2//)-ones. Phthalazin-l(2iT)-one itself is prepared from naphthalene by oxidation, subsequent treatment with hydrazine and decarboxylation as shown in Scheme 77 (55YZ1423,64FRP1335759). 4-Substituted phthalazin-l(2iT)-ones are prepared in a similar way from 2-acylbenzoic acids. 3-Hydroxyphthalides,... 

Solids Discharge The type of discharge mechanism utilized is dependent upon the necessity of sealing the atmosphere inside the fluidized-bea reactor and the subsequent treatment of the sohds. The simplest solids discharge is an overflow weir. This can be used only when the escape of fluidizing gas does not present any hazards due to... 

At one time the requirement for phenol (melting point 41°C), eould be met by distillation of eoal tar and subsequent treatment of the middle oil with eaustic soda to extraet the phenols. Such tar acid distillation products, sometimes containing up to 20% o-cresol, are still used in resin manufacture but the bulk of phenol available today is obtained synthetically from benzene or other chemicals by such processes as the sulphonation process, the Raschig process and the cumene process. Synthetic phenol is a purer product and thus has the advantage of giving rise to less variability in the condensation reactions. 

Subsequent treatment of the sticklac carried out by hand or by mechanical methods first involves removal of woody matter and washing to remove the associated lac dye to produce seedlac, containing 3-8% of impurities. This may be further refined by various methods to produce the shellac flakes of commerce. 

A typical physical-chemical treatment system incorporates three "dual" medial (sand anthracite) filters connected in parallel in its treatment train. The major maintenance consideration with granular medial filtration is the handling of the backwash. The backwash will generally contain a high concentration of contaminants and require subsequent treatment. 

The primary advantage of aerobic digestion is that it produces a biologically stable end product suitable for subsequent treatment in a variety of processes. Volatile solids reductions similar to anaerobic digestion are possible. Some parameters affecting the aerobic digestion process are ... 

In many cases, if it is not feasible to contain a runaway reaction within the reactor, it may be possible to pipe the emergency device effluent to a separate pressure vessel for containment and subsequent treatment. 

---