Commercialized products

A mixture of polymethylene glycols of the type (CH20) ,xH20 where n is 6- 50. It is a white, amorphous powder having the odour of meth-anal, m.p. I20-130°C. The commercial product contains 95% methanal and is obtained in while flocculent masses when solutions of methanal are evaporated or allowed to stand. When heated it is converted to methanal. Used as a convenient solid substitute for methanal. 

Moreover, certain commercial products should meet specifications including those for fractions distilled at certain temperatures. 

The distillation initial and end points are not specified because their determination is not very accurate the values obtained for commercial products are found to be between 160 and 180°C for the initial point and between 350 and 385°C for the end point. 

The luminometer index (ASTM D 1740) is a characteristic that is becoming less frequently used. It is determined using the standard lamp mentioned above, except that the lamp is equipped with thermocouples allowing measurement of temperatures corresponding to different flame heights, and a photo-electric cell to evaluate the luminosity. The jet fuel under test is compared to two pure hydrocarbons tetraline and iso-octane to which are attributed the indices 0 and 100, respectively. The values often observed in commercial products usually vary between 40 and 70 the official specification is around 45 for TRO. 

The specifications require a maximum Conradson Carbon of 0.35%. This limit is very easily met in fact the values obtained on commercial products rarely exceed 0.1%. On the other hand, for heavy fuels, the Conradson Carbon can often reach 5 to 10%, as we will show later. 

The tendency of the color to become darker with time is often indicative of chemical degradation. The test is conducted with the aid of a colorimeter (NF T 60-104 and ASTM D 1500) and by comparison with colored glass standards. The scale varies from 0.5 to 8. The French specifications stipulate that diesel fuel color should be less than 5, which corresponds to an orange-brown tint. Generally, commercial products are light yellow with indices from 1 to 2. 

Until 1992, the total sulfur content of jet fuel was limited to 0.2 wt. %. Starting in 1993, a reduction to 0.1% was instituted apparently without major incident since for commercial products, lower levels (to 500 ppm) had been observed very often. 

The French specification for sulfur in all types of gasolines —regular, premium, with or without lead— is 0.1% maximum, that is, 1000 ppm. This value is easily achieved because in the majority of commercial products, the content is less than 500 ppm. 

The commercial production of carbon monoxide in the form of water gas is now largely obsolete. The production by the reaction between steam and hydrocarbons is considered later (p. 180). 

The HyperChem philosophy associated with back end computations is one which is in tended to in still eon fiden ce. as far as is possible. in the scientific results emanating from HyperChem. This ph ilosoph y is on e of open n ess — open n ess aboii t the prod net. the calculations being performed, the science embodied in the product, etc. Apart from protecting the proprietary code associated with a commercial product. Hypercube wushes to document and describe as fully as is possible tb e calculation s th at HypcrCb cm performs. There should be no mystery about the scientific results obtained with HyperChem. 

Reasonably pure solvents are required for many organic reactions and for recrystaUisations methods for obtaining these from commercial products will accordingly be described. Frequently, the pure solvent (e.g., the analytical reagent) can be purchased, but the cost is usually iiigh, particularly if comparatively large volumes are required. Furthermore, it is excellent practice for the student to purify inexpensive commercial solvents. 

Di-teo-propyl ether. The commercial product usually contains appreciable quantities of peroxides these should be removed by treatment with an acidified solution of a ferrous salt or with a solution of sodium sulphite (see under Diethyl ether). The ether is then dried with anhydrous calcium chloride and distilled. Pure di-iao-propyl ether has b.p. 68-5°/760 mm. 

Mono-alkyl ethers of ethylene glycol, ROCHjCHjOH. The mono methyl, ethyl and n-butyl ethers are inexpensive and are known as methyl cellosolve, cellosolve, and butyl cellosolve respectively. They are completely miscible with water, and are excellent solvents. The commercial products are purified by drying over anhydrous potassium carbonate or anhydrous calcium sulphate, followed by fractionation after... 

Chloroform. The commercial product contains up to 1 per cent, of ethyl alcohol, which is added as a stabiliser. The alcohol may be removed by either of the following procedures —... 

Bromine. The commercial product may be dried (and partially purified) by shaking with an equal volume of concentrated sulphuric acid, and then separating the acid. Chlorine, If present, may be removed by fractionation in an all-glass apparatus from pure potassium bromide the b.p. is 59°/760 mm. The analytical reagent grade is satisfactory for most purposes where pure bromine is required. 

This secondary amyl alcohol (2-pentanol) is a commercial product (Sharpies Solvent Corporation, etc.). 

The simpler nitrop>arafIins (nitromethane, nitroethane, 1- and 2-nitroproj)ane) are now cheap commercial products. They are obtained by the vapour phase nitration of the hydrocarbons a gaseous mixture of two mols of hydrocarbon and 1 mol of nitric acid vapour is passed through a narrow reaction tube at 420-476°. Thus with methane at 476° a 13 per cent, conversion into nitro methane is obtained ethane at 420° gives a 9 1 mixture of nitroethane (b.p. 114°) and nitromethane (b.p. 102°) propane at 420° afifords a 21 per cent, yield of a complex mixture of 1- (b.p. 130-6°) and 2-nitropropane (b.p. 120°), nitroethane and nitromethane, which are separated by fractional distillation. 

The preparation of these compounds in the laboratory is not recommended and is rarely worth while because of the cheapness of the commercial products. Dimethyl sulphate is a heavy liquid, boiling at 188-6°, and is practically without odour. The vapour is highly poisonous and the substance should only be used in a fume cupboard with a good draught. The liquid itself is readily absorbed through the skin, with toxic results. 

Undecylenic acid (or 10-undecenoic acid) (I), a comparatively inexpensive commercial product obtained from castor oil, reacts with bromine in dry carbon tetrachloride to give 10 11-dibromoundecoic acid (II), which upon heating with a concentrated solution of potassium hydroxide yields 10-niidecynoic acid (III) ... 

I) Dry carbon tetrachloride may be prepared by distillation of the commercial product and rejection of the first 20 per cent, of the distillation. 

Secondary and tertiary amines are not generally prepared in the laboratory. On the technical scale methylaniline is prepared by heating a mixture of aniline hydrochloride (55 parts) and methyl alcohol (16 parts) at 120° in an autoclave. For dimethylaniline, aniline and methyl alcohol are mixed in the proportion of 80 78, 8 parts of concentrated sulphuric acid are added and the mixture heated in an autoclave at 230-235° and a pressure of 25-30 atmospheres. Ethyl- and diethyl-anihne are prepared similarly. One method of isolating pure methyl- or ethyl-aniline from the commercial product consists in converting it into the Y-nitroso derivative with nitrous acid, followed by reduction of the nitroso compound with tin and hydrochloric acid ... 

Make a thin paste of 21 5 g. of finely-powdered o-tolidine (a commercial product) with 300 ml. of water in a 1-litre beaker, add 25 g. (21 ml.) of concentrated hydrochloric acid, and warm until dissolved. Cool the solution to 10° with ice, stir mechanically, and add a further 25 g. (21 ml.) of concentrated hydrochloric acid (1) partial separation of o tolidine dihydrochloride will occur. Add a solution of 15 g, of sodium nitrite in 30 ml. of water as rapidly as possible, but keep the temperature below 15° a slight excess of nitrous acid is not harmful in this preparation. Add the clear, orange tetrazonium solution to 175 ml. of 30 per cent, hypophosphorous acid (2), and allow the mixture to stand, loosely stoppered, at room temperature for 16-18 hours. Transfer to a separatory funnel, and remove the upper red oily layer. Extract the aqueous layer with 50 ml, of benzene. Dry the combined upper layer and benzene extract with anhydrous magnesium sulphate, and remove the benzene by distillation (compare Fig. II, 13, 4) from a Widmer or similar flask (Figs. II, 24, 3-5) heat in an oil bath to 150° to ensure the removal of the last traces of benzene. Distil the residue at ca. 3 mm. pressure and a temperature of 155°. Collect the 3 3 -dimethyldiphenyl as a pale yellow liquid at 114-115°/3 mm. raise the bath temperature to about 170° when the temperature of the thermometer in the flask commences to fall. The yield is 14 g. 

The carbon tetrachloride may bo dried by distilling the commercial product and rejecting the first 10 per cent, of the distillate. 

The commercial product, m.p. 53-55°, may be used. Alternatively the methyl -naphthyl ketone may be prepared from naphthalene as described in Section IV,136. The Friedel - Crafts reaction in nitrobenzene solution yields about 90 per cent, of the p-ketone and 10 per cent, of the a-ketone in carbon disulphide solution at — 15°, the proportions ore 65 per cent, of the a- and 35 per cent, of the p-isomer. With chlorobenzene ns the reaction medium, a high proportion of the a-ketone is also formed. Separation of the liquid a-isomer from the solid p-isomer in Such mixtures (which remain liquid at the ordinary temp>erature) is readily effected through the picrates the picrate of the liquid a-aceto compound is less soluble and the higher melting. 

S e Section I1.50,S. The commercial product, obtained soon after its preparation from the manufacturers, is satisfiEictory. 

Acetoacetanilide is an inexpensive commercial product. If necessary, it may bo recrystallised from 50 per cent, ethanol m.p. 84-85°. 

Pure acrylonitrile boils at 78°. Acrylonitrile vapour is highly toxic it should therefore be handled with due caution and all operations with it should be conducted in a fume cupboard provided with an efficient draught. Acrylonitrile forms an azeotropic mixture with water, b.p. 70-5° (12-5 per cent, water). The commercial product may contain tte polymer it should be redistilled before use and the fraction b.p. 76 -5-78° collected separately as a colourless liquid. 

Prepare anhydrous tert.-butyl alcohol by refluxing the commercial product with sodium ca. 4 g. per 100 ml.) until the metal is about two-thirds dissolved and then distilling. Free metal should be present during the distillation. 

Hydrazine hydrate of 95-100 per cent, concentration is a commercial product. The 40-60 per cent, solution may be concentrated to 80-85 per cent, strength by distillation with xylene in an all-glass apparatus. 

Until World War 11, there was no commercial production of elemental fluorine. The nuclear bomb project and nuclear energy applications, however, made it necessary to produce large quantities. 

The method of obtaining aluminum metal by the electrolysis of alumina dissolved in cryolite was discovered in 1886 by Hall in the U.S. and at about the same time by Heroult in France. Cryolite, a natural ore found in Greenland, is no longer widely used in commercial production, but has been replaced by an artificial mixture of sodium, aluminum, and calcium fluorides. 

Commercial production from petroleum ash holds promise as an important source of the element. High-purity ductile vanadium can be obtained by reduction of vanadium trichloride with magnesium or with magnesium-sodium mixtures. 

Synthesis Control will be needed in the condensation as the ketone C is more reacfiye than the acid D both in enolisation and electrophilic power. The Reformatsky looks a good method. Again we don t know how this commercial product is actually made ... 

The other main illogical electrophiles are epoxides, easily made from an olefin and a per-acid, the usual one being m-chloroperbenzoic acid (MCPBA) a commercial product. A more detailed explanation comes later, in fiiames 276-7. 

You see that vacuum adapter stuck to the top of the condenser in fig. 7a Well, a closer look at it in fig. 7b will show that it has some drying agent sandwiched between two cotton balls and the nipple (tee heel) sealed with plastic wrap or foil. The drying agent can be either a commercial product called Drierite or calcium chloride. This attachment is placed on top of a condenser when refluxing solutions that have no water in them and must remain that way during the time they are refluxed. All this is to prevent moisture in the outside air from coming into contact with the cold surface of the of the inside walls of the condenser. This will surely happen and the condensed outside-air water will drip down into the reaction flask and ruin the experiment. This is not so much a... 

General note All reagents and glassware should be dry. The best way to obtain dry THF is to shake the commercial product with machine-powdered KOH (about 70 g/1) and distil the filtered liquid from a small amount of Li A1 Hi,. 

To a vigorously stirred suspension of 2 mol of lithium amide in 2 1 of liquid atimonia (see II, Exp. 11) was added in 15 min 1 mol of propargyl alcohol (commercial product, distilled in a partial vacuum before use). Subsequently, 1 mol of butyl bromide was added dropwise in 75 min. After an additional 1.5 h, stirring was stopped and the ammonia was allovied to evaporate. To the solid residue were added 500 ml of ice-water. After the solid mass had dissolved, six extractions with diethyl ether were performed. The (unwashed) combined extracts were dried over magnesium sulfate and then concentrated in a water-pump vacuum. Distillation of the residue through a 40-cm Vigreux column afforded 2-heptyn-l-ol, b.p. 

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