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Patent US3884776 (http://l2.espacenet.com/dips/viewer?PN=US3884776&CY=gb&LG=en&DB=EPD)
Post 182782 (missing)
(PolytheneSam: "Re: potassium dichromate", Chemicals & Equipment)Patent US3423300 (http://l2.espacenet.com/dips/viewer?PN=US3423300&CY=gb&LG=en&DB=EPD)
Patent US3450623 (http://l2.espacenet.com/dips/viewer?PN=US3450623&CY=gb&LG=en&DB=EPD)
Patent US3726914 (http://l2.espacenet.com/dips/viewer?PN=US3726914&CY=gb&LG=en&DB=EPD)
Patent US3824160 (http://l2.espacenet.com/dips/viewer?PN=US3824160&CY=gb&LG=en&DB=EPD)
Patent US5127999 (http://l2.espacenet.com/dips/viewer?PN=US5127999&CY=gb&LG=en&DB=EPD)
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Post 271991 (https://www.thevespiary.org/talk/index.php?topic=9102.msg27199100#msg27199100)
(hypo: "first encouraging ketenelamp experiment", Methods Discourse)Post 247901 (missing)
(Osmium: "Re: Acetic Anhydride", Chemicals & Equipment)Post 200799 (missing)
(Osmium: "Re: Relativly simply Acetic Anhydride Synth.", Chemistry Discourse)Patent US2259895 (http://l2.espacenet.com/dips/viewer?PN=US2259895&CY=gb&LG=en&DB=EPD)
Patent US6387238 (http://l2.espacenet.com/dips/viewer?PN=US6387238&CY=gb&LG=en&DB=EPD)
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http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=6387238 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=6387238)
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Patent GB3998 (http://l2.espacenet.com/dips/viewer?PN=GB3998&CY=gb&LG=en&DB=EPD)
;. J.S.C.I. 1896, 15, 668), Fournier (Patent GB7887 (http://l2.espacenet.com/dips/viewer?PN=GB7887&CY=gb&LG=en&DB=EPD)
, J.S.C.I. 1897, 16, 695), and Lang (ibid. 1903, 571). Wertheim recommended the oxidation alcohol with a mixture of sulphuric acid, nitric acid, and sodium bichromate in a stream carbon dioxide (J. Amer. Chem. Soc. 1913, 35 689, 698), whilst Adams and Williams.(ibid. 1921. 43, 2420) stated that the yield of aldehyde by the ordinary chromic oxidation is greatly improved by very vigorous stirring of the mixture. Other methods of preparation are: distillation of calcium acetate with calcium formate (Limpricht, Annalen, 1856, 97, 369), distillation of lactic acid with manganese dioxide and sulphuric acid (Stadeler, Annalen, 1851, 79, 333„ or by the action of dilute sulphuric acid alone (Erlenmeyer, Zeitsch. f. Chemie, 1868, 4, 343).Patent GB5533 (http://l2.espacenet.com/dips/viewer?PN=GB5533&CY=gb&LG=en&DB=EPD)
. Various aliphatic acids such as succinic, glyceric, maleic, fumaric, tartaric, etc., yield acetaldehyde on treatment with Fenton's reagent in sunlight (Neuberg, Biochem. Z. 1914, 47, 50).Patent US1124347 (http://l2.espacenet.com/dips/viewer?PN=US1124347&CY=gb&LG=en&DB=EPD)
) has also claimed a method which consists in passing the vapour of alcohol into a heated porous earthenware tube containing platinum or palladium and drawing off the hydrogen produced which diffuses through the walls of the tubes. It is doubtful if this is a practicable method. The Sabatier-Senderens method has, however, in recent years become the basis of a very important branch of the organic chemical industry which is demonstrated both by the number of patent applications and by the erection of large works in Great Britain, Germany, the United States and elsewhere, for the manufacture of acetaldehyde from ethyl alcohol.Patent GB132120 (http://l2.espacenet.com/dips/viewer?PN=GB132120&CY=gb&LG=en&DB=EPD)
) claims the oxidation of alcohol to acetaldehyde in an apparatus identical with that described inPatent GB126479 (http://l2.espacenet.com/dips/viewer?PN=GB126479&CY=gb&LG=en&DB=EPD)
for converting methyl alcohol to formaldehyde. Groombridge, Oxley, and British Celanese Ltd. introduce oxygen and alcohol vapour into the reaction zone through perforated conduits at several points parallel to the line of flow of the reaction mixture (Patent GB391444 (http://l2.espacenet.com/dips/viewer?PN=GB391444&CY=gb&LG=en&DB=EPD)
), whilst water may be removed by cooling the issuing vapours to 40°-70C°, the acetaldehyde being then absorbed directly in glacial acetic acid for oxidation (Patent GB390186 (http://l2.espacenet.com/dips/viewer?PN=GB390186&CY=gb&LG=en&DB=EPD)
,Patent GB390211 (http://l2.espacenet.com/dips/viewer?PN=GB390211&CY=gb&LG=en&DB=EPD)
); the same inventors also claim the use of a heat-interchange system in which the reaction bed exchanges heat with a climbing film of cooling liquid (Patent GB390186 (http://l2.espacenet.com/dips/viewer?PN=GB390186&CY=gb&LG=en&DB=EPD)
,Patent GB390504 (http://l2.espacenet.com/dips/viewer?PN=GB390504&CY=gb&LG=en&DB=EPD)
).Patent GB389134 (http://l2.espacenet.com/dips/viewer?PN=GB389134&CY=gb&LG=en&DB=EPD)
). The use of silver deposited upon copper as a catalyst is described inPatent GB425550 (http://l2.espacenet.com/dips/viewer?PN=GB425550&CY=gb&LG=en&DB=EPD)
. The water produced in the reaction may be partially removed by treatment with a dehydrating agent such as calcium chloride, etc. (Patent GB389135 (http://l2.espacenet.com/dips/viewer?PN=GB389135&CY=gb&LG=en&DB=EPD)
), or the water and unchanged alcohol may be removed as a ternary mixture by treatment with benzene, the acetaldehyde remaining in vapour form (Patent GB389145 (http://l2.espacenet.com/dips/viewer?PN=GB389145&CY=gb&LG=en&DB=EPD)
), or the moist acetaldehyde vapour may be cooled to 40°-70° to condense the water with only a small amount of acetaldehyde (Patent GB390211 (http://l2.espacenet.com/dips/viewer?PN=GB390211&CY=gb&LG=en&DB=EPD)
); lastly the acetaldehyde itself may be separated by extraction at 100°-150° with a solvent miscible with water, such as chlorobenzene or paraffin oil (Patent GB390506 (http://l2.espacenet.com/dips/viewer?PN=GB390506&CY=gb&LG=en&DB=EPD)
).Patent GB287846 (http://l2.espacenet.com/dips/viewer?PN=GB287846&CY=gb&LG=en&DB=EPD)
); again, on passing alcohol vapour over a catalyst consisting essentially of a basic zinc chromite, copper chromite, manganese chromite, etc., the product consists mainly of acetaldehyde and n-butyl alcohol, with lesser amounts of n-butyl alcohol (Patent GB313575 (http://l2.espacenet.com/dips/viewer?PN=GB313575&CY=gb&LG=en&DB=EPD)
. Cf. also Adkins, Folkers, and Kinsey, J. Amer. Chem. Soc. 1931, 53, 2714, 4220 ; Ind. Eng. Chem. 1932, 24, 314). For the normal process a catalyst is recommended consisting of electrolytic silver crystals impregnated with a small amount (e.g. 1%) of the oxides of Al, Cr, Ce, Mo, Th, V, W, or Zn (Patent US1968552 (http://l2.espacenet.com/dips/viewer?PN=US1968552&CY=gb&LG=en&DB=EPD)
). Scalione and Frazer effect the oxidation of alcohol in presence of free oxygen, by using a metal oxide catalyst which has been prepared by drying below 150° or in a current of neutral gas below 200° (Patent GB166285 (http://l2.espacenet.com/dips/viewer?PN=GB166285&CY=gb&LG=en&DB=EPD)
). Holzverkohlungs Industrie A.-G. claim a 92.3% conversion by using a silver gauze catalyst, a similar method being claimed by Goldschmidt inPatent GB290523 (http://l2.espacenet.com/dips/viewer?PN=GB290523&CY=gb&LG=en&DB=EPD)
, using a silver catalyst at 400°-420°C. Woolcock and Imperial Chemical Industries, Ltd., pass alcohol vapour with air through silver gauze discs contained in a copper tube (Patent GB325105 (http://l2.espacenet.com/dips/viewer?PN=GB325105&CY=gb&LG=en&DB=EPD)
), whilst Boehringer and Soehne recommend the addition of 0.2% of CeO2 to the reduced copper catalyst. Wiesler, Peake, and British Industrial Solvents, Ltd., obtain acetaldehyde by passing alcohol vapour, steam and air over copper at 420°-440° or silver gauze at 450°-500°, or over the AgVO3 or Cu(N03)2 at 350°-400°C. (Patent GB353071 (http://l2.espacenet.com/dips/viewer?PN=GB353071&CY=gb&LG=en&DB=EPD)
). Monsanto Chemical Works claim the use as catalysts of vanadyl zeolites prepared by forming complex silicates containing vanadium in non-exchangeable form, with or without other chemical groups such as boric, phosphoric, tungstic, molybdic, stannic, or plumbic acids, combined with zinc, aluminium, chromium, etc. (Patent GB298142 (http://l2.espacenet.com/dips/viewer?PN=GB298142&CY=gb&LG=en&DB=EPD)
). InPatent GB294037 (http://l2.espacenet.com/dips/viewer?PN=GB294037&CY=gb&LG=en&DB=EPD)
Fuchs and Holzverkohlungs Industrie A.-G. dry the reaction products by cooling, and then extract the aldehyde by means of a solvent such as aldol, acetic acid, alcohol, etc., the resultant solutions being then polymerised, oxidised, or reduced to yield more aldol, acetic acid, or alcohol respectively. Young and Carbide and Carbon Chemicals Corpn., inPatent US1977750 (http://l2.espacenet.com/dips/viewer?PN=US1977750&CY=gb&LG=en&DB=EPD)
, pass the vapour of alcohol at 225°-350°C. over a reduced copper catalyst containing not more than 5% of Cr, prepared by impregnating an inert carrier with a concentrated solution of 545 parts cupric nitrate and 118 parts chromic nitrate, the mass being dried, roasted at 600°, and then heated at 250°C. in a stream of alcohol vapour.Patent GB29073 (http://l2.espacenet.com/dips/viewer?PN=GB29073&CY=gb&LG=en&DB=EPD)
), in which a process is claimed consisting in passing acetylene into a solution of a mercury salt in an organic or inorganic acid below 70°C. (e.g. sulphuric, phosphoric, acetic, chloracetic acids). The use of 45% sulphuric acid mixed with mercuric oxide isPatent DE425665 (http://l2.espacenet.com/dips/viewer?PN=DE425665&CY=gb&LG=en&DB=EPD)
, was only granted on Feb. 11, 1926, with extension of "life"; it was later acquired by I.G. Farbenind. A.-G. This patent covered the process for the production of acetaldehyde by passing a continuous stream of acetylene through dilute sulphuric acid containing a mercury catalyst. A general discussion of the priority of earlier patents is given in Z. angew.Patent GB15669 (http://l2.espacenet.com/dips/viewer?PN=GB15669&CY=gb&LG=en&DB=EPD)
) claim the use of a 20-35% aqueous solution of sulphuric, phosphoric, or an organic sulphonic acid, etc., containing a mercury salt, the temperature being kept below the boiling-point. The Consort. f. Elektrochem. Ind. G.m.b.H. describe a modification consisting in passing acetylene through sulphuric acid solutions of mercury oxide, containing less than 60 parts SO4 per 1,000 parts of water, at temperatures above 70°C. (Patent GB6000 (http://l2.espacenet.com/dips/viewer?PN=GB6000&CY=gb&LG=en&DB=EPD)
). The aldehyde distils off as it is formed and mercury is deposited at the bottom of the liquid; the patent also claims an electrolytic process for re-oxidising the mercury which is gradually formed by reduction during the process. InPatent GB16848 (http://l2.espacenet.com/dips/viewer?PN=GB16848&CY=gb&LG=en&DB=EPD)
, the same firm describe a process in which the acetaldehyde is swept out of the solution as it is formed, by a stream of excess acetylene, the aldehyde being removed and the residual gas recirculated (see alsoPatent GB208689 (http://l2.espacenet.com/dips/viewer?PN=GB208689&CY=gb&LG=en&DB=EPD)
). Fr. Bayer and Co. (Patent GB6527 (http://l2.espacenet.com/dips/viewer?PN=GB6527&CY=gb&LG=en&DB=EPD)
) claimed a similar process, the sulphuric acid being replaced by an organic sulphonic acid, e.g. benzene sulphonic acid (di- or tri-sulphonic acids), etc., the object being to avoid the condensation and polymerisation of the acetaldehyde which is caused by the prolonged action of stronger acids, such as mineral acids.Patent GB15919 (http://l2.espacenet.com/dips/viewer?PN=GB15919&CY=gb&LG=en&DB=EPD)
recommends the production of a catalytic liquid by dissolving a mercuric salt in a suitable solvent and then forming the sulphate in situ, by the addition of sulphuric acid; the process is,Patent GB16957 (http://l2.espacenet.com/dips/viewer?PN=GB16957&CY=gb&LG=en&DB=EPD)
) consists in so adjusting the rate of flow of the acetylene and the temperature of the reaction vessel that the heatPatent GB5132 (http://l2.espacenet.com/dips/viewer?PN=GB5132&CY=gb&LG=en&DB=EPD)
) is concerned mainly with the use of solvents such as glacial acetic acid, ethylidene diacetate, etc., in the presence of mercuric oxide and a strong acid, water being added continuously in the theoretical proportions.Patent GB132557 (http://l2.espacenet.com/dips/viewer?PN=GB132557&CY=gb&LG=en&DB=EPD)
; continuity is maintained by the periodicPatent GB105064 (http://l2.espacenet.com/dips/viewer?PN=GB105064&CY=gb&LG=en&DB=EPD)
) recommends the use of sulphuric acid of 5-20% at a temperature below 60°C., the acetylene being led in at such a rate that all is absorbed. The acetylene is introduced slowly at first until all the mercury compound present (5-20%) has become grey or greyish-black. The acetaldehyde formed may be removed periodically either by distillation or by extraction with solvents such as tetraehlorethane, etc., water being added at intervals. InPatent GB106483 (http://l2.espacenet.com/dips/viewer?PN=GB106483&CY=gb&LG=en&DB=EPD)
Dreyfus modifies his process by using sulphuric acid of more than 20% and extracting the acetaldehyde with suitable solvents.Patent GB380928 (http://l2.espacenet.com/dips/viewer?PN=GB380928&CY=gb&LG=en&DB=EPD)
.Patent US1213486 (http://l2.espacenet.com/dips/viewer?PN=US1213486&CY=gb&LG=en&DB=EPD)
,Patent US1213487 (http://l2.espacenet.com/dips/viewer?PN=US1213487&CY=gb&LG=en&DB=EPD)
,Patent US1247270 (http://l2.espacenet.com/dips/viewer?PN=US1247270&CY=gb&LG=en&DB=EPD)
;Patent CA181655 (http://l2.espacenet.com/dips/viewer?PN=CA181655&CY=gb&LG=en&DB=EPD)
), by the introduction of a salt of a weak acid, e.g. a borate, into the catalytic mercury solution ; the absorption of the acetylene and distillation of the acetaldehyde is stated to be more complete. A claim is also made for the use of several catalytic baths arranged in series to ensure complete absorption. InPatent GB260305 (http://l2.espacenet.com/dips/viewer?PN=GB260305&CY=gb&LG=en&DB=EPD)
the Consort. f. Elektrochem. Ind. G.m.b.H. recommend the catalytic hydration of acetylene in presence of a solvent for the gas, such as phenols, ketones, acetals, esters, etc. I.G. Farbenind. A.-G. claim the catalytic production of acetaldehyde from acetylene in presence of mercuric salts, at pressures exceeding 2 atm., the method being especially applicable to mixtures containing dilute acetylene obtained by the thermal decomposition of hydrocarbons ([patent]GB 278324[patent]); they also claim the use of a catalyst comprising a solution of an alkali metal bi-sulphate, containing a mercury salt, or a salt of a heavy metal of the 1st or the 8th groups of the periodic system, such as copper or iron (Patent GB312716 (http://l2.espacenet.com/dips/viewer?PN=GB312716&CY=gb&LG=en&DB=EPD)
), whilst inPatent GB319542 (http://l2.espacenet.com/dips/viewer?PN=GB319542&CY=gb&LG=en&DB=EPD)
a claim is made for the use of a solution of mercuric and ammonium salts for effecting the hydration; the use of slightly increased pressures, temperatures above 85°C., and an excess of acetylene is recommended inPatent GB349022 (http://l2.espacenet.com/dips/viewer?PN=GB349022&CY=gb&LG=en&DB=EPD)
. The same inventors claim the use of heated concentrated aqueous solutions of salts having a slightly acid reaction, such as the chlorides of zinc, chromium, magnesium, calcium or ferric iron, in presence of mercuric oxide or uranyl nitrate (Patent GB313864 (http://l2.espacenet.com/dips/viewer?PN=GB313864&CY=gb&LG=en&DB=EPD)
); this last process may be modified by the use of increased pressure with the addition of a small amount of water, insufficient to destroy the acid reaction but enough to lower the boiling-point to at least 4°C. below the boiling-point of the corresponding saturated solution (Patent GB393690 (http://l2.espacenet.com/dips/viewer?PN=GB393690&CY=gb&LG=en&DB=EPD)
).Patent GB124702 (http://l2.espacenet.com/dips/viewer?PN=GB124702&CY=gb&LG=en&DB=EPD)
,Patent GB125926 (http://l2.espacenet.com/dips/viewer?PN=GB125926&CY=gb&LG=en&DB=EPD)
); or by lead peroxide, manganese dioxide, or ceric oxide (Patent GB131084 (http://l2.espacenet.com/dips/viewer?PN=GB131084&CY=gb&LG=en&DB=EPD)
). The Soc. Chem. Ind. in Basle regenerate the catalyst by electrolysis in presence of a suitable oxygen carrier such as an iron salt (Patent GB130138 (http://l2.espacenet.com/dips/viewer?PN=GB130138&CY=gb&LG=en&DB=EPD)
); more generally, however, the formation of mercury sludge is prevented or delayed by the introduction into the catalytic liquor of oxidising agents such as chromic acid, chromates, or in particular ferric salts (Meister, Lucius, and Briining,Patent GB24153 (http://l2.espacenet.com/dips/viewer?PN=GB24153&CY=gb&LG=en&DB=EPD)
;Patent DE293070 (http://l2.espacenet.com/dips/viewer?PN=DE293070&CY=gb&LG=en&DB=EPD)
;Patent US1151928 (http://l2.espacenet.com/dips/viewer?PN=US1151928&CY=gb&LG=en&DB=EPD)
,Patent US1151929 (http://l2.espacenet.com/dips/viewer?PN=US1151929&CY=gb&LG=en&DB=EPD)
). Riley and Imperial Chemical Industries, Ltd., recommend the use as a catalyst of a mercury salt solution containing ferric sulphate, a portion of the liquor being continuously removed, reoxidised by oxygen, and returned to the process (Patent GB346883 (http://l2.espacenet.com/dips/viewer?PN=GB346883&CY=gb&LG=en&DB=EPD)
). Alternatively, the catalyst may be prepared by mixing mercury with a suitable oxidizing agent such as ferric oxide, and then adding dilute sulphuric acid (Soc. Anon. de Prod. Chim. Etabl. Maletra,Patent GB140785 (http://l2.espacenet.com/dips/viewer?PN=GB140785&CY=gb&LG=en&DB=EPD)
). A continuous regeneration process using electrolytic oxidation with a platinum anode and mercury cathode is described by the Chem. Fabr. Griesheim-Elektron inPatent GB143891 (http://l2.espacenet.com/dips/viewer?PN=GB143891&CY=gb&LG=en&DB=EPD)
. Again, the spent reaction liquor ofPatent GB140785 (http://l2.espacenet.com/dips/viewer?PN=GB140785&CY=gb&LG=en&DB=EPD)
(v.s.) may be regenerated by first removing all aldehyde present, precipitating the mercury from the solution by means of iron filings, and finally reoxidising the ferrous salt solution by electrolysis (Soc. Anon. de Prod. Chim. ]tabl. Maletra,Patent GB165085 (http://l2.espacenet.com/dips/viewer?PN=GB165085&CY=gb&LG=en&DB=EPD)
). As an alternative the sludge itself may be removed and treated in various ways to revivify it or to recover the mercury: thus the Chem. Fabr. Griesheim-Elektron advise carbonising the residue by heat or else mixing the sludge with caustic lye and electrolysing (Patent GB10140 (http://l2.espacenet.com/dips/viewer?PN=GB10140&CY=gb&LG=en&DB=EPD)
). Matheson also recommends letting the sludge settle, neutralising with alkali and heating to 125°C.; the liquid mercury is then run off, the residue being ground up and carbonised by heating it to 100°-500°C. (Patent GB132559 (http://l2.espacenet.com/dips/viewer?PN=GB132559&CY=gb&LG=en&DB=EPD)
). Riley, Rowell, and Imperial Chemical Industries, Ltd., recover the mercury by treating the sludge with chlorine and removing the resultant mercuric chloride solution (Patent GB332106 (http://l2.espacenet.com/dips/viewer?PN=GB332106&CY=gb&LG=en&DB=EPD)
); whilst Hirst, Rowell and Imperial Chemical Industries, Ltd., suggest treating the sludge with strong nitric acid and then adding concentrated sulphuric acid to precipitate mercuric and ferric sulphates (Patent GB309888 (http://l2.espacenet.com/dips/viewer?PN=GB309888&CY=gb&LG=en&DB=EPD)
). The Chem. Fabr. Worms A.-G. advise heating the spent catalytic material with iron powder or other reducing agent to 200°C. for several hours (Patent GB156187 (http://l2.espacenet.com/dips/viewer?PN=GB156187&CY=gb&LG=en&DB=EPD)
).Patent GB132560 (http://l2.espacenet.com/dips/viewer?PN=GB132560&CY=gb&LG=en&DB=EPD)
; cf. Canad. Chem. J. 1919, 3, 259); mercury and dilute aqueous caustic soda are placed in a large cast-iron pan, 6 ft. in diameter and 15 ins. high, oxidation being effected with current density of about 55 amps. per sq.Patent DE311173 (http://l2.espacenet.com/dips/viewer?PN=DE311173&CY=gb&LG=en&DB=EPD)
)Patent GB107584 (http://l2.espacenet.com/dips/viewer?PN=GB107584&CY=gb&LG=en&DB=EPD)
). The Chemische Fabrik Rhenania suggest passing the same mixture over bog iron ore at 400°-420°C., or over hydrated iron oxide, bauxite, hydrated aluminium silicates, or compounds of copper, nickel, chromium, vanadium, etc. (Patent GB109983 (http://l2.espacenet.com/dips/viewer?PN=GB109983&CY=gb&LG=en&DB=EPD)
; cf. also [patent]GB 107585[patent]). I.G. Farbenind. A.-G. claim the production of acetaldehyde by passing acetylene and steam over non-volatile mercuric compounds such as the phosphate, vanadate or sulphate in presence, if desired, of silver or tin vanadates ; in presence of air acetic acid is formed (Patent GB321241 (http://l2.espacenet.com/dips/viewer?PN=GB321241&CY=gb&LG=en&DB=EPD)
). Again, the catalyst may consist of silico-tungstic acid deposited on clay, or basic zinc tungstate (Patent GB329867 (http://l2.espacenet.com/dips/viewer?PN=GB329867&CY=gb&LG=en&DB=EPD)
), or it may comprise alumina activated by dehydrogenating catalysts such as cadmium oxide, zinc oxide, cadmium sulphide, or zinc sulphide together with the corresponding chromates, tungstates, molybdates, etc. (Patent GB332635 (http://l2.espacenet.com/dips/viewer?PN=GB332635&CY=gb&LG=en&DB=EPD)
). Acetaldehyde may also be obtained by passing a mixture of approximately equal volumes of acetylene and steam over a catalyst comprising, for example, zinc oxide, manganese dioxide and chromic acid, at 180°-200°C. (Mittasch, Pier, Winkler, and I.G. Farbenind. A.-G.,Patent DE415686 (http://l2.espacenet.com/dips/viewer?PN=DE415686&CY=gb&LG=en&DB=EPD)
). In a later patent by the same firm it is proposed to pass a mixture of acetylene, steam and oxygen, saturated with mercury vapour at 200°-260°C., over a mixed catalyst such as mercuric phosphate with other heavy metal oxides and/or salts, deposited on pumice, clay, etc. (Patent GB364255 (http://l2.espacenet.com/dips/viewer?PN=GB364255&CY=gb&LG=en&DB=EPD)
). Wohl (Patent GB154579 (http://l2.espacenet.com/dips/viewer?PN=GB154579&CY=gb&LG=en&DB=EPD)
) recommends passing a mixture of air, steam, and acetylene over a heavy metal salt which is stable below 300°-400°C., such as basic zinc chloride, basic zinc vanadate, molybdate or chromate; the product consists of acetaldehyde with some acetic acid. A similar process of the Consort. f. Elektrochem. Ind. A.-G. (Patent GB373893 (http://l2.espacenet.com/dips/viewer?PN=GB373893&CY=gb&LG=en&DB=EPD)
) consists in passing acetylene and steam through molten zinc chloride, with or without the addition of (BaSO4+ZnO) or a mixture of oxides such as CeO2, ZnO, Cr Os, MnO, BaO, TiO2, etc., at 300°-450°C., the exit vapours being then passed over a heated solid catalyst to complete the conversion, if desired. In a modified process acetylene and oxygen, together with small amounts of nitrogen oxides and in substantial absence of steam, are passed over heated quartz or porcelain at 287°-407°, to yield acetaldehyde and acetic acid Gutehoffnungshutte Oberhausen A.-G.,Patent GB376045 (http://l2.espacenet.com/dips/viewer?PN=GB376045&CY=gb&LG=en&DB=EPD)
). Horsley, Tanner, and Imperial Chemical Industries, Ltd., recommend the use of a catalyst composed of zinc oxide and a molybdate, at 300°-350°C. (Patent GB334427 (http://l2.espacenet.com/dips/viewer?PN=GB334427&CY=gb&LG=en&DB=EPD)
), or of bismuth salts such as the phosphate or molybdate, using a large excess of steam in the process (Patent GB344638 (http://l2.espacenet.com/dips/viewer?PN=GB344638&CY=gb&LG=en&DB=EPD)
), whilst by the use of cadmium phosphate at 300°-400°C. acetaldehyde and crotonaldehyde are produced (Patent GB346288 (http://l2.espacenet.com/dips/viewer?PN=GB346288&CY=gb&LG=en&DB=EPD)
), or the catalyst may consist of boron trioxide and phosphoric acid ("boron phosphate") at 200 -400°C. (Patent GB351016 (http://l2.espacenet.com/dips/viewer?PN=GB351016&CY=gb&LG=en&DB=EPD)
). Traun's Forschungslaboratorium proposes to obtain acetaldehyde by hydrating acetylene with steam at 250°-300°C./5-10 atm. in presence of small quantities of acetic, sulphuric, or organic sulphonic acids, etc. (Patent GB156152 (http://l2.espacenet.com/dips/viewer?PN=GB156152&CY=gb&LG=en&DB=EPD)
), whilst I.G. Farbenind. A.-G. propose passing gases containing acetylene through concentrated aqueous solutions of neutral salts at 140°, the salts having an acid reaction in concentrated solutions (e.g. salts of zinc, cadmium, chromium, etc.), and the residual gases are then further catalytically hydrated, for example, by passage at 300°400°C. over a mixture of the oxides of aluminium, tungsten, and zinc (Patent GB313864 (http://l2.espacenet.com/dips/viewer?PN=GB313864&CY=gb&LG=en&DB=EPD)
,Patent GB425069 (http://l2.espacenet.com/dips/viewer?PN=GB425069&CY=gb&LG=en&DB=EPD)
). I.G. Farbenind. A.-G., inPatent GB340787 (http://l2.espacenet.com/dips/viewer?PN=GB340787&CY=gb&LG=en&DB=EPD)
, claim a process for the purification, prior to conversion to acetaldehyde, of acetylene-rich gases produced thermo-electrically, by passing the gases over porous carbon or silica gel; they also claim the use of mercuric phosphate, at temperatures above 120°C., for the hydration of crude dilute acetylene, or the use of silver vanadate on active carbon at 250°C. or over (Patent GB304855 (http://l2.espacenet.com/dips/viewer?PN=GB304855&CY=gb&LG=en&DB=EPD)
). The production of acetaldehyde from dilute mixtures containing 2-10% of acetylene, by washing the gases in a counter-current with a suitable mercuric sulphate catalyst solution, is claimed by Hirst and Imperial Chemical Industries, Ltd., inPatent GB302515 (http://l2.espacenet.com/dips/viewer?PN=GB302515&CY=gb&LG=en&DB=EPD)
. The same problem is also dealt with inPatent GB414347 (http://l2.espacenet.com/dips/viewer?PN=GB414347&CY=gb&LG=en&DB=EPD)
(Murphree and Standard Oil Co.).Patent GB331185 (http://l2.espacenet.com/dips/viewer?PN=GB331185&CY=gb&LG=en&DB=EPD)
); the same firm inPatent GB334223 (http://l2.espacenet.com/dips/viewer?PN=GB334223&CY=gb&LG=en&DB=EPD)
describes the manufacture of ethyl alcohol by leading acetylene, saturated with water vapour at 90°C., first over zinc oxide or silica gel, etc., at 380°C., and then, admixed with hydrogen, over nickel at 200°C. A general description of preparing acetaldehyde from acetylene is given by Thommen in Chem.-Ztg. 1934, 58, 797. Benson and Cadenhead note the occurrence of diacetyl, and of other potentially valuable by-products in the synthesis of acetaldehyde from acetylene (J.S.C.I. 1934, 54, 40T).Patent GB115899 (http://l2.espacenet.com/dips/viewer?PN=GB115899&CY=gb&LG=en&DB=EPD)
. Comp. de Prod. Chim. d'Alais describe the production of acetaldehyde from acetylene in an apparatus in which the reaction liquid is subjected continuously to a vacuum so as to remove the acetaldehyde as it is formed (Patent GB130650 (http://l2.espacenet.com/dips/viewer?PN=GB130650&CY=gb&LG=en&DB=EPD)
). As originally carried out on the large scale at the Shawinigan works of Canadian Electro-products, Ltd., acetylene gas was led into dilute sulphuric acid containing mercuric oxide in pension, the oxide being added continuously and the acetaldehyde carried off in the excess of acetylene used (Canad. Chem. J. 1919, 3, 260). Seller, Hotz, and the British Cellulose and Chemical Co. recommend that parts of the apparatus exposed to the action of sulphuric acid shall be of lead, coated electrolytically with lead peroxide (Patent GB151086 (http://l2.espacenet.com/dips/viewer?PN=GB151086&CY=gb&LG=en&DB=EPD)
) (cf. alsoPatent GB105064 (http://l2.espacenet.com/dips/viewer?PN=GB105064&CY=gb&LG=en&DB=EPD)
, Dreyfus). InPatent GB155776 (http://l2.espacenet.com/dips/viewer?PN=GB155776&CY=gb&LG=en&DB=EPD)
andPatent GB217747 (http://l2.espacenet.com/dips/viewer?PN=GB217747&CY=gb&LG=en&DB=EPD)
Brutkus describes apparatus for producing acetaldehyde from acetylene and water vapour in a type of compressor in which they are brought to reaction during compression strokes, temperature and pressure being maintained constant by injection of a spray of water. InPatent GB294227 (http://l2.espacenet.com/dips/viewer?PN=GB294227&CY=gb&LG=en&DB=EPD)
(void) (Karpiti and Hilbsch a plant is described in which the acetylene and the absorbing solution are maintained in separate circulatory systems having the reaction chamber in common. I.G. Farbenind. A.-G. inPatent GB299234 (http://l2.espacenet.com/dips/viewer?PN=GB299234&CY=gb&LG=en&DB=EPD)
(grant of patent refused) claim the use of chromium-nickel steel for the construction or lining of the apparatus, whilst inPatent GB298108 (http://l2.espacenet.com/dips/viewer?PN=GB298108&CY=gb&LG=en&DB=EPD)
Harter describes a form of vessel including a rotating fan, or impeller, made of, or coated with, platinum so that a stream of acetylene, steam, and oxygen may be impelled through the vessel and caused to react with production of acetaldehyde. Small amounts of acetaldehyde are formed, together with ethylene glycol, on hydrolysing dichlorethane with water and barium carbonate at 160°-180°C. for 1 hour (Askenasy and Heller,Patent US1928240 (http://l2.espacenet.com/dips/viewer?PN=US1928240&CY=gb&LG=en&DB=EPD)
). Emeleus (J.C.S. 1929, 1733) states that acetaldehyde is formed to the extent of about 10% in the phosphorescent cold flame of ether, whilst Marie and Lejeune (Anal. Ffs. Quim. 1930, 27, 447) describe a method of electrolysing ether in presence of perchloric acid which affords acetaldehyde in 30% yield.Patent GB226248 (http://l2.espacenet.com/dips/viewer?PN=GB226248&CY=gb&LG=en&DB=EPD)
,Patent GB337409 (http://l2.espacenet.com/dips/viewer?PN=GB337409&CY=gb&LG=en&DB=EPD)
). Walker and the Empire Gas and Fuel Co. also claim the production of methanol, formaldehyde and acetaldehyde by a similar process from natural gas, coal gas, shale gas, oil gas, etc. (Patent GB295356 (http://l2.espacenet.com/dips/viewer?PN=GB295356&CY=gb&LG=en&DB=EPD)
, void). InPatent GB304623 (http://l2.espacenet.com/dips/viewer?PN=GB304623&CY=gb&LG=en&DB=EPD)
the I.G. Farbenind. A.-G. claim the production of acetaldehyde, formaldehyde and formic acid from hydrocarbons and air under the influence of the silent electric discharge; the same firm also notes the production of acetaldehyde as a byproduct obtained on passing hydrocarbon mixtures, together with steam and air, over catalysts such as oxides of manganese, vanadium, chromium, aluminium, etc., at 500°-800°C. (Patent GB305603 (http://l2.espacenet.com/dips/viewer?PN=GB305603&CY=gb&LG=en&DB=EPD)
). InPatent GB267925 (http://l2.espacenet.com/dips/viewer?PN=GB267925&CY=gb&LG=en&DB=EPD)
the same firm describes the preparation of acetaldehyde by passing carbon monoxide and acetic acid vapour at 200°-550° over a mixture of iron and cobalt; whilst Dreyfus reduces waste or dilute acetic acid to acetaldehyde by catalytic reduction with hydrogen, using finely divided nickel, iron, zinc, tin, lead, pumice, etc., as catalysts (Patent GB273810 (http://l2.espacenet.com/dips/viewer?PN=GB273810&CY=gb&LG=en&DB=EPD)
). The formation of acetaldehyde as a by-product during the catalytic oxidation of various gaseous hydrocarbons at 350°-600° is noted inPatent GB321494 (http://l2.espacenet.com/dips/viewer?PN=GB321494&CY=gb&LG=en&DB=EPD)
(Arnold and Standard Oil Development Co., Ltd.), whilst Gutehoffnungshutte Oberhausen A.-G. note the production of acetaldehyde and formaldehyde by treating a mixture of methane and carbon dioxide with a high-frequency field of 20,000 volts or over, at cycles greater than 10,000 per second (Patent GB353455 (http://l2.espacenet.com/dips/viewer?PN=GB353455&CY=gb&LG=en&DB=EPD)
). Behrens describes the production of acetaldehyde by mixing the gases obtained by distilling coal, wood, turf, etc., with 5-6% of carbon dioxide and heating the mixture for some time (Patent DE276764 (http://l2.espacenet.com/dips/viewer?PN=DE276764&CY=gb&LG=en&DB=EPD)
). Aldehyde is also formed to some extent by heating charcoal saturated with acetylene to 350°C. with water (Degriz, Ann. Chim. Phys. 1894 [vii], 3, 216). I.G. Farbenind. A.-G. claim the production of acetaldehyde by passing ethylene oxide over a reduced catalyst such as one prepared from copper carbonate and magnesium ammonium phosphate, at 180°-200°C. (Patent GB331185 (http://l2.espacenet.com/dips/viewer?PN=GB331185&CY=gb&LG=en&DB=EPD)
). A more unusual claim is made by Curme consisting in passing ethylene into a solution of a mercuric salt, the compound produced being then subjected to anodic oxidation to produce acetaldehyde, which is removed continuously by distillation (Patent US1315543 (http://l2.espacenet.com/dips/viewer?PN=US1315543&CY=gb&LG=en&DB=EPD)
,Patent US1315546 (http://l2.espacenet.com/dips/viewer?PN=US1315546&CY=gb&LG=en&DB=EPD)
).Post 417762 (missing)
(Rhodium: "Isosafrole Wacker - MDP2P in 69% yield", Novel Discourse) for other reasons - it deals with the Wacker oxidation of a whole lot of alkenes, not just ethylene.J. Chem. Soc. Chem. Commun. 1272-1273 (1988) (https://www.thevespiary.org/rhodium/Rhodium/pdf/ethene2ethanal.fuelcell.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/ethene2ethanal.fuelcell.pdf) deals with the oxidation of a C2H4/H2O mixture to CH3CHO on one side, and reduction of O2 to H2O on the other of a { Pd|H3PO4|Pd } fuel cell system (which acts as a proton transfer medium between the different half-reactions) at between 45-122°C.Patent GB425973 (http://l2.espacenet.com/dips/viewer?PN=GB425973&CY=gb&LG=en&DB=EPD)
names contact time at different temperatures and related conversion. More important it tells the density of the actone vapours at about 75°C and gives a an example to calculate flow contact time etc.Patent DE1049845 (http://l2.espacenet.com/dips/viewer?PN=DE1049845&CY=gb&LG=en&DB=EPD)
Patent DE1061767 (http://l2.espacenet.com/dips/viewer?PN=DE1061767&CY=gb&LG=en&DB=EPD)
Patent DE1080994 (http://l2.espacenet.com/dips/viewer?PN=DE1080994&CY=gb&LG=en&DB=EPD)
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_imgs/djvu.gif)