Water of saturation

Both catalyst activity and tar formation are directly affected by the state of hydration of the phosphoric acid-kieselguhr type of catalyst. At the higher temperature it is more difficult to maintain proper hydration. Hydration control is required because the catalyst has an optimum water content which determines the activity and selectivity of the catalyst. The water-vapor pressure varies at different catalyst temperatures and it is important to keep the water content of the hydrocarbon in equilibrium with that of the catalyst. In those units where water of saturation in the feed is insufficient, additional water must be injected into the feed as catalyst requirements dictate. The solid phosphoric acid type of catalyst contains the proper amount of water when manufactured and the art of catalyst hydration has reached such a point that catalyst in properly operated polymerization units no longer fails from coke formation or loss of activity. 

The proposed overall process flow-scheme for the treatment of very sour gases (i.e., with an acid gas content above 20%) with re-injection of the separated acid gases to a disposal reservoir incorporates a special patented H2S pre-extraction step upstream of the Activated M DEA acid gas removal process. In this upstream step [10], called SPREX, a substantial amount of the H2S and some of the CO2 are pre-removed from the wet raw gas as a pumpable liquid stream. This liquid will essentially contain by solubility all the water of saturation that comes with the inlet raw gas. It will also contain some of the incoming hydrocarbons. Figure 10.6 depicts a process flow diagram of this special pre-extraction and Activated MDEA combination process. 

Air leaks in system. This results in overloading the vacuum system because of excess noncondensibles and water of saturation in noncondensible stream. Air leakage must be stopped to correct the problem. 

Oxidation to acids. Varm together in a small conical flask on a water-bath for lo minutes a mixture of 0 5 ml. of benzaldehyde or salicylaldehyde, 15 ml. of saturated KMn04 solution, and 0-5 g. of NajCOj. Then acidify with cone. HCl, and add 25% sodium sulphite solution until the precipitated manganese dioxide has redissolved. On cooling, benzoic or salicylic acid crystallises out. 

I. Oxidation to benzoic acid. Boil a mixture of i ml. of benzyl chloride, 50 ml. of saturated aqueous KMn04 solution and 2 g. of anhydrous Na.jCOj under reflux for 30 minutes. Acidify with cone. HCl and then add 25% Na SOj solution until the brown precipitate of MnOj has dissolved. On cooling, benzoic acid crystallises out. Filter through a small Buchner funnel, wash with water and identify (P 347) When recrystallised from water, benzoic acid has m.p. 121 . 

Add a known volume ofo oaM.AgNOj solution (in excess) and boil the solution until the silver chloride has coagulated. Filter through a conical 5 cm. funnel, ensuring that the filter-paper does not protrude above the r m of the funnel. Wash the silver chloride and the filter-paper several times with a fine jet of distilled water. To the united filtrate and washings add i ml. of saturated ferric alum solution. The solution should be almost colourless if it is more than faintly coloured, add a few drops of concentrated nitric acid. Then titrate with 0 02M-ammonium thiocyanate solution until the permanent colour of ferric thiocyanate is just perceptible. (Alternatively the chloride may be determined potentiometrically.)... 

Metallic sodium. This metal is employed for the drying of ethers and of saturated and aromatic hydrocarbons. The bulk of the water should first be removed from the liquid or solution by a preliminary drying with anhydrous calcium chloride or magnesium sulphate. Sodium is most effective in the form of fine wire, which is forced directly into the liquid by means of a sodium press (see under Ether, Section II,47,i) a large surface is thus presented to the liquid. It cannot be used for any compound with which it reacts or which is affected by alkalis or is easily subject to reduction (due to the hydrogen evolved during the dehydration), viz., alcohols, acids, esters, organic halides, ketones, aldehydes, and some amines. 

Commercial diethyl carbonate may be purified by the following process. Wash 100 ml. of diethyl carbonate successively with 20 ml. of 10 per cent, sodium carbonate solution, 20 ml. of saturated calcium chloride solution, and 25 ml. of water. Allow to stand for one hour over anhydrous calcium chloride with occasional shaking, filter into a dry fiask containing 5 g. of the same desiccant, and allow to stand for a further hour. Distil and collect the fraction boiling at 125-126°. Diethyl carbonate combines with anhydrous calcium chloride slowly and prolonged contact should therefore be avoided. Anhydrous calcium sulphate may also be used. 

An alternative method for isolating the n-butyl ether utilises the fact that n-butyl alcohol is soluble in saturated calcium chloride solution whilst n-butyl ether is slightly soluble. Cool the reaction mixture in ice and transfer to a separatory fimnel. Wash cautiously with 100 ml. of 2-5-3N sodium hydroxide solution the washings should be alkaline to litmus. Then wash with 30 ml. of water, followed by 30 ml. of saturated calcium chloride solution. Dry with 2-3 g. of anhydrous calcium chloride, filter and distil. Collect the di-n-butyl ether at 139-142°. The yield is 20 g. 

Method- 3. From platinum metal or platinum residues. Dissolve the platinum metal or platinum residues in aqua regia, evaporate just to dryness several times with concentrated hydrochloric acid, dissolve the final residue in a httle water and precipitate as ammonium chloro-platinate with excess of saturated ammonium chloride solution. Filter and dry the precipitate at 100°. Then proceed according to Method 1. 

Ethyl S-n-butyl xanthate. Use 32 g. of potassium ethyl xanthate, 37 g. (23 ml.) of n-butyl iodide (Section 111,40) and 50 ml. of absolute ethyl alcohol. Reflux on a water bath for 3 hours. Pour into 150 ml. of water, saturate with salt (in order to facilitate the separation of the upper layer), remove the upper xanthate layer, wash it once with 25 ml. of saturated salt solution, and dry with anhydrous calcium chloride or anhydrous calcium sulphate. Distil from a 50 ml. Claisen flask under reduced pressure. Collect the pale yellow ethyl S-n-butyl xanthate at 90-91°/4 mm. The yield is 34 g. 

Pour the resulting dark reddish-brown liquid into 500 ml. of water to which 17 ml. of saturated sodium bisulphite solution has been added (the latter to remove the excess of bromine). Steam distil the resulting mixture (Fig. II, 41,1) , collect the first portion of the distillate, which contains a little unchanged nitrobenzene, separately. Collect about 4 litres of distillate. Filter the yellow crystalline solid at the pump, and press well to remove the adhering liquid. The resulting crude m-bromonitrobenzene, m.p. 51-52°, weighs 110 g. If required pure, distil under reduced pressure (Fig. II, 19, 1) and collect the fraction of b.p. 117-118°/9 mm. it then melts at 56° and the recovery is about 85 per cent. 

Myristic acid from hexanoic acid and methyl hydrogen sebacate). Dissolve 23 -2 g. of redistilled hexanoic acid (re caproic acid), b.p. 204-6-205-5°/760 mm., and 21-6 g. of methyl hydrogen sebacate in 200 ml. of absolute methanol to which 0 13 g. of sodium has been added. Electrolyse at 2 0 amps., whilst maintaining the temperature between 30° and 40°, until the pH is about 8 0 (ca. 6 hours). Neutralise the contents of the electrolysis cell with a little acetic acid and distil off the methyl alcohol on a water bath. Dissolve the residue in 200 ml. of ether, wash with three 50 ml. portions of saturated sodium bicarbonate solution, once with water, dry with anhydrous magnesium sulphate, and distil with the aid of a fractionating column (see under Methyl hydrogen adipate). Collect the re-decane at 60°/10 mm. (3 0 g.), the methyl myristate at 158-160°/ 10 mm. (12 5g.) and dimethyl hexadecane-1 16-dicarboxylate at 215-230°/ 7 mm. (1 -5 g.)... 

The purified commercial di-n-butyl d-tartrate, m.p. 22°, may be used. It may be prepared by using the procedure described under i o-propyl lactate (Section 111,102). Place a mixture of 75 g. of d-tartaric acid, 10 g. of Zeo-Karb 225/H, 110 g. (136 ml.) of redistilled n-butyl alcohol and 150 ml. of sodium-dried benzene in a 1-litre three-necked flask equipped with a mercury-sealed stirrer, a double surface condenser and an automatic water separator (see Fig. Ill, 126,1). Reflux the mixture with stirring for 10 hours about 21 ml. of water collect in the water separator. FUter off the ion-exchange resin at the pump and wash it with two 30-40 ml. portions of hot benzene. Wash the combined filtrate and washings with two 75 ml. portions of saturated sodium bicarbonate solution, followed by lOu ml. of water, and dry over anhydrous magnesium sulphate. Remove the benzene by distillation under reduced pressure (water pump) and finally distil the residue. Collect the di-n-butyl d-tartrate at 150°/1 5 mm. The yield is 90 g. 

Saponification of esters. Aqueous sodium hydroxide method. To hydrolyse an ester of an alcohol, reflux 5-6 g. with 50 ml. of 20 per cent, sodium hydroxide solution for 1-2 hours or until the ester layer disappears. Distil the alkahne mixture and collect about 6 ml. of distillate. This will contain any volatile alcohol formed in the saponification. If the alcohol does not separate, i.e., is water-soluble, saturate the distillate with sohd potassium carbonate an upper layer of alcohol is then usually formed. (The alcohol may be subsequently identified as the 3 5-dinitrobenzoate see Section 111,27,2.) Cool the residual alkahne mixture, and acidify it with dilute sulphuric acid. If no crystalline acid is precipitated, the acid may frequently be isolated by ether extraction, or it may be distilled from the acidified solution and isolated from (or investigated in) the distfllate. (The acid may be subsequently identified, e.g., as the S benzyl wo-thiuronium salt see Section 111,85,2.)... 

D. Now the ether will be a deep reddish yellow. Distill off the ether...quack...and take the temp up to 170 C to drive off any other volatiles. Should recover 90%+ of the original weight of oil. Now add 500 ml of saturated bisulfite and stir for 1.5 hours...Quack Vacuum Filter, the duck fat crystals Wash with water and ether, yield dull fine ppt in the filter cake...stable bisulfite addition product...can be stored forever...QuackU Yield -50 to 80% depending on a ducks technique ... 

A solution of a-lithiomethoxyallene was prepared from nethoxyal lene and 0.20 mol of ethyllithiurn (note 1) in about 200 ml of diethyl ether (see Chapter II, Exp. 15). The solution was cooled to -50°C and 0.20 mol of ethylene oxide was added immediately. The cooling bath was removed temporarily and the temperature was allowed to rise to -15 c and was kept at this level for 2.5 h. The mixture was then poured into 200 ml of saturated ammonium chloride solution, to which a few millilitres of aqueous ammonia had been added (note 2). After shaking the layers were separated. The aqueous layer was extracted six times with small portions of diethyl ether. The combined ethereal solutions were dried over sodium sulfate and subsequently concentrated in a water-pump vacuum. Distillation of the... 

The solution was then poured into 200 ml of saturated ammonium chloride solution. After vigorous shaking the upper layer was separated off and the aqueous layer was extracted three times with diethyl ether. The combined ethereal solutions were dried over magnesium sulfate and then concentrated in a water-pump vacuum. 

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