Separation dilution

Acid circulated over SO absorbing towers is maintained at about 98.5% to minimize its vapor pressure. Where lower concentration product acid is desired, it is made either in separate dilution faciUties, or in drying towers operated at 93—96% H2SO4. 

The acid extract phase is separated, diluted with water, and heated to regenerate isobutylene. The isobutylene is then caustic and water washed to remove traces of acid, distillation dried, and rerun. The unreacted C4 stream, containing normal butenes, is also caustic washed before further processing. 

Preparation of 5a,6a-0xido-17a-Hydroxya//opregnane-3,20-dione 3,20-Bis-(Ethy ene Ketal) A solution was prepared by heating 19.96 g (0.0477 mol) of 17a-hydroxyprogesterone 3,20-bis-(ethylene ketal) and 500 ml of benzene. After the solution was effected the flask was cooled to 5°C and a mixture of 3.68 g (0.0449 mol) of sodium acetate and 174 ml of 40% peracetic acid was added with stirring. The reaction mixture was stirred in the ice bath for 3 hours. The lower peracid layer was separated, diluted with water and extracted twice with benzene. 

Preparation of 2-nitro-2-methyl-1 -propanol-nitrate. 50g of the 2-nitro-2-methyl-1-propanol purified as above were sifted into a mixt of 58.5g of 90.5% nitric acid.and 241,5g of 103.1% sulfuric acid (oleum) while the well-agitated mixt was maintained close to 15°. Stirring was continued for 1 hour and the mixt allowed to stand for hour. No separation of the nitration product occurred and the mixt was poured over cracked ice. An oily layer separated. The mixt was transferred to a separatory funnel, washed with water, Na bicarbonate, and twice with water to neutrality. The separated diluted spent acid together with the washings were thoroughly extracted with ether, the ether extract washed to neutrality and added to the main product. 

The unsaturated aldehyde (0.1 mol) is added to a two-phase system of thiolacetic acid (7.6, 0.1 mol) in aqueous NaOH (50%, 16 ml) and TBA-I (0.1 g, 0.27 mmol) in CH2CI2 (100 ml) over a period of ca. 30 min at 0°C. The mixture is stirred for 2.5 h at 0°C and then heated under reflux for 20 min. The organic phase is separated, diluted with Et20 (50 ml), washed with H20 (3 x 25 ml), and dried (MgS04). Evaporation of the solvent gives i-formyl-5-thiacyclohex-l-ene (41%) from acrolein and 1-formyl-4,6-dimethyl-5-thiacyclo-hex-l-ene (81%) from crotonaldehyde. 

Preparation of -aminoethylsulfuric acid [31]. Ethanolamine (6 moles, 366 gm) and 98 % sulfuric acid (6 moles, 600 gm) are separately diluted with half their weight of water and cooled in an ice bath. The amine is slowly added to the acid with constant stirring in a flask also cooled in an ice bath. The mixture is boiled under reduced pressure with the aid of an aspirator. Boiling stones are used to prevent lumping. When the temperature of the liquid reaches 140°-160°C, the heating is stopped and the material solidifies. The product is not isolated, but methanol or ethanol is added in order to wash the product free from any remaining sulfuric acid or ethanolamine. The yield is approximately 761-804 gm (90-95 %). 

Radiochemical purity should be demonstrated by one or preferably two separate dilution analyses as described in Section 6b, or by degradation experiments together with dilution analysis. Neglect of this important... 

When nitration is complete the mixture is run into a separator, diluted with water and allowed to settle. After a time the layers are separated, the nitrobenzene being washed with a little dilute sodium carbonate solution. 

The rheology of a polymer solution increases with the polymer concentration. A transition exists at the so-called critical concentration (which decreases with increasing molecular mass) separating "dilute" from "concentrated" solutions. 

No support can be regarded as inert with respect to the active centres. By its universally positive effect on the activity of centres, MgCl2 is superior to any other support. In spite of the great technical importance of Mg in active centres, generally not much is known of their structure in third-generation catalysts (or perhaps because of its positive effects all the important producers have published hundreds of patents, but the crucial factors may still be kept secret). It is suspected that the separation (dilution) of transition metal atoms by a barrier of Mg atoms enables the majority of transition metals to become part of the active centres on these centres, the polymer grows more rapidly than on centres without Mg. Mutual contact of the centres is hindered, bimolecular termination of centres (transition metal reduction to a less active oxidation state) is limited, and the centres live longer. 

Consider new separation devices that efficiently separate dilute species. 

Zeolite adsorbents (mostly A-lype and X-type, LTA and FAU, respectively, and to a lesser extent Mordenite, MOR and Y, FAU) are used in a number of processes related to bulk gas separations, dilute impurity removal, drying and chromatography (Table 3). 

Separation, dilution Separation, dilution Dilution Direct... 

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