Washing process

Ethyl acetate. Use 58 g. (73-5 ml.) of absolute ethyl alcohol, 225 g. of glacial acetic acid and 3 g. of concentrated sulphuric acid. Reflux for 6-12 hours. Work up as for n-propyl acetate. B.p. 76- 77°. Yield 32 g. Much ethyl acetate is lost in the washing process. A better yield may be obtained, and most of the excess of acetic acid may be recovered, by distilhng the reaction mixture through an efficient fractionating column and proceeding as for methyl acetate. 

Method 1. From ammonium chloroplatinate. Place 3 0 g. of ammonium chloroplatinate and 30 g. of A.R. sodium nitrate (1) in Pyrex beaker or porcelain casserole and heat gently at first until the rapid evolution of gas slackens, and then more strongly until a temperature of about 300° is reached. This operation occupies about 15 minutes, and there is no spattering. Maintain the fluid mass at 500-530° for 30 minutes, and allow the mixture to cool. Treat the sohd mass with 50 ml. of water. The brown precipitate of platinum oxide (PtOj.HjO) settles to the bottom. Wash it once or twice by decantation, filter througha hardened filter paper on a Gooch crucible, and wash on the filter until practically free from nitrates. Stop the washing process immediately the precipitate tends to become colloidal (2) traces of sodium nitrate do not affect the efficiency of the catalyst. Dry the oxide in a desiccator, and weigh out portions of the dried material as required. 

It is essential to remove all the zinc salts in the washing process, otherwise the product largely resinihes during the distillation. 

If an emulsion should form during the washing process, add about 10 ml. of carbon tetrachloride (for details, see under Methyl Benzoate,. Section IV,176). 

Place 75 g. (74 ml.) of benzyl cyanide (Section IV,160), 125 g. (153 ml.) of rectifled spirit and 150 g. (68 ml.) of concentrated sulphuric acid in a 750 ml. round-bottomed flask, fitted with an efficient reflux condenser. Reflux the mixture, which soon separates into Wo layers, gently for 8 hoius, cool and pour into 350 ml. of water. Separate the upper layer. Dissolve it in about 75 ml. of ether (1) in order to facilitate the separation of the layers in the subsequent washing process. Wash the ethereal solution carefully with concentrated sodium bicarbonate solution until effervescence ceases and then with water. Dry over 10 g. of anh3 drous magnesium sulphate for at least 30 minutes. Remove the solvent with the aid of the apparatus shown in Fig. II, 13, 4 and distil from an air bath (Fig. II, 5, 3). The ethyl phenylacetate passes over at 225-229° (mainly 228°) as a colourless liquid the yield is 90 g. Alternatively, the residue after removal of the ether may be distilled in a Claisen flask under diminished pressm (Fig. II, 20, 1) collect the ester at 116-lI8°/20 mm. 

Sorted plastic packaging materials are shipped, usually in bales, to processing plants to be converted to polymer resins. The bales are broken and the bottles sorted to ensure that only one type of polymer is further processed. Processing consists of chopping and grinding the bottles into flakes. These flakes are washed. Processing steps such as flotation are used to remove polymeric contaminants from the flakes (15,16). The flakes are melted and converted into pellets. 

Detergency is mainly affected by the concentration and stmcture of surfactant, hardness and builders present, and the nature of the soil and substrate. Other important factors include wash temperature length of time of washing process mechanical action relative amounts of sod, substrate, and bath, generally expressed as the bath ratio, ie, the ratio of the bath weight to substrate weight and rinse conditions. 

All-in Method. Start at 25°C with sequestrant, salt, and alkah (mixed soda ash and caustic), mn for 15 min, and add dyes over 10 min. Run for a further 15 min and bring the temperature up to 80°C over 45 min. Maintain this temperature for 30—60 min before dropping the dyebath and starting the washing process. 

Bacterial a-amylases used in laundry detergents are fully compatible with detergent proteases, ie, the two enzymes work together in the wash process. During storage in both powder and Hquid detergents, the amylases are very stable in the presence of proteases. 

Upases. The idea of using Upases in the wash process dates back to 1913 when O. Rn hm suggested a dding pancreatin [8049-47-6] to detergent formulations. Many patents have demonstrated that Upases can improve the removal of fatty stains when used in powder and liquid detergents, special presoakers, or other cleaning agents. Intense research activity is also reflected in the literature (43—45). 

A typical enzymatic stone-washing process (76) is as follows load garments into industrial laundry machine, add water, and heat to 50—60°C. Adjust pH to 6.0 with acetic acid or buffer. Desize garment with a-amylase for 10—15 min, and drain water. Add new water, heat to 55—60°C, adjust pH to 6.5—7.0, and add ceUulase. Tumble for 20—90 min, drain, rinse twice, and dry. 

A Buchner funnel may be used, but filtration through paper is very slow. The washing process may be carried out by centrifugation instead of filtration. 

The catalyst should be kept wet with the solvent during the washing process, as it is pyrophoric. 

Schlamm-verfahren, n. elutriating or washing process, -vorrichtung, /. elutriating apparatus, washing apparatus. 

Quenching Outside Seals (only) For oxidizing and corrosive liquids, seal liquid washes process fluid, for high temp. 3-29... 

The most efficient washing of the hydroxide was achieved applying a three-step process using an ammonium carbonate solution as the first step, followed by an ammonia solution, and water as the final step. This washing process brings about a ten-fold reduction in the concentration of fluorine compared with laboratory and industrial experience, in which a 2-4 fold reduction in the fluorine content of tantalum or niobium hydroxides following a one-step washing process was obtained. 

The physical nature of the precipitate must be such that it can be readily separated from the solution by filtration, and can be washed free of soluble impurities. These conditions require that the particles are of such size that they do not pass through the filtering medium, and that the particle size is unaffected (or, at least, not diminished) by the washing process. 

With tellurium, precipitation of the element with sulphur dioxide is slow in dilute hydrochloric acid solution and does not take place at all in the presence of excess of acid moreover, the precipitated element is so finely divided that it oxidises readily in the subsequent washing process. Satisfactory results are obtained by the use of a mixture of sulphur dioxide and hydrazinium chloride... 

---