Small scale distillation

The material to be steam-distilled (mixed with some water if a solid compound, but not otherwise) is placed in C, and a vigorous current of steam blown in from D. The mixture in C is thus rapidly heated, and the vapour of the organic compound mixed with steam passes over and is condensed in E. For distillations on a small scale it is not necessary to heat C if, however, the flask C contains a large volume of material or material which requires prolonged distillation, it should be heated by a Bunsen burner, otherwise the steady condensation of steam in C will produce too great a volume of liquid. 

Reflux Distillation Unit. The apparatus shown in Fig. 38 is a specially designed distillation-unit that can be used for boiling liquids under reflux, followed by distillation. The unit consists of a vertical water-condenser A, the top of which is fused to the side-arm condenser B. The flask C is attached by a cork to A. This apparatus is particularly suitable for the hydrolysis of esters (p. 99) and anilides (p. 109), on a small scale. For example an ester is heated under reflux with sodium hydroxide solution while water is passed through the vertical condenser water is then run out of the vertical condenser and passed through the inclined condenser. The rate of heating is increased and any volatile product will then distil over. 

Steam generator. For small scale work the steam generator D, Fig. 15, p. 33) is too cumbersome for the production of a small amount of steam. It is preferable to use a 250 ml. conical flask fitted with cork containing a vertical safety tube and an outlet-tube (Fig. 44). Care should be taken that the length of rubber tubing connecting the steam oudet tube to the flask containing the materi to be distilled should be as short as possible and should not contain kinks. 

Small scale apparatus with interchangeable ground glass joints (compare Section 11,56) are available commercially. One set of apparatus ( A) is based largely upon BlO and B14 joints, although occasionally a larger size joint is used as in the steam distillation apparatus shown in Fig. XII, 3, 1. 

If a small-scale special apparatus is not available, proceed as follows Place 1-5 g. (1-9 ml.) of re-butyl alcohol and 0 28 g. of purified red phosphorus in a 25 ml. round-bottomed flask, and add 2-5 g. of io ne in 2 portions. Allow to stand for 2-3 minutes, heat on a boiling water bath under reflux for 30 minutes, add 5 ml. of water and distil. Separate the lower layer of the distillate. Work up the product as described in 111,40. 

With the exception of the soHd methoxide [19727-40-3], the lower antimony trialkoxides are colorless or slightly colored distillable Hquids, easily hydroly2ed. Thermally these alkoxides are rather stable. The lower antimony trialkoxides are manufactured from antimony trichloride, the higher from antimony trioxide, both on a small scale. They are used in polyester manufacture, in fireproofing, as catalysts, and for coatings. For further information about antimony trialkoxides, see references 21, 65, 98. 

Boron Triiodide. Boron ttiiodide is not manufactured on a large scale. Small-scale production of BI from boron and iodine is possible in the temperature range 700—900°C (70—72). Excess I2 can be removed as Snl by reaction with Sn, followed by distillation (71). The reaction of metal tetrahydroborates and I2 is convenient for laboratory preparation of BI (73,74). BI can also by synthesized from B2H and HI in a furnace at 250°C (75), or by the reaction of B with excess Agl or Cul between 450—700°C, under vacuum (76). High purity BI has been prepared by the reaction of I2 with mixtures of boron carbide and calcium carbide at elevated temperatures. 

It may be purified by recrystallization from hot hydrochloric add, as recommended in Org. Syn. 3, 87, but on account of the difficulty of filtration this procedure is satisfactory on a small scale only. It is preferably distilled in 200-g. lots from a 500-cc. Claisen flask under 10-15 mm. pressure, b.p. 160-165V12 mm. It is important that no air inlet be used to prevent bumping, since under these conditions it partly sublimes and causes trouble by stopping up the connections. A filter or distilling flask is used as a receiver and only a short but wide bore (10 mm.) air condenser is necessary. This product is pale yellow and melts at 95-96°. The yield from 200 g. of crude product is 180-185 g-... 

The compound, prepared by by co-condensation of diethyl sulfite (3.5 mmol) and chlorine fluoride (10 mmol) at —196°C, followed by slow warming to —78, then —20°, is unstable. Trap-to-trap distillation must be effected with great care, as violent explosions occurred (even on this small scale) when cryogenic cooling was removed from the traps. Scaling up is not recommended. 

Following a patented procedure for the conversion of 2,4-dinitrochlorobenzene to 5-chloro-2-nitrophenol, 2,4-difluoronitrobenzene was treated with sodium hydroxide in hot aqueous dioxane containing a phase transfer catalyst. On the small scale, the reaction and isolation of 5-fluoro-2-nitrophenol, including vacuum distillation, were uneventful. On the 20 1 scale, vacuum distillation of combined batches of the crude product led to onset of decomposition at 150°C, which could not be controlled, and the residue erupted with explosive violence and a small fire ensued. Thermal examination of fresh small-scale crude material has shown that it is capable of highly exothermic decomposition, with onset of the exotherm at 150°C (ARC). It was then realised that difficulty in controlling the reaction temperature had been experienced on the 20 1 scale. It is recommended that this procedure and purification should not be attempted on so large a scale. 

Small-scale preparation is recommended [1], in view of a previous explosion through superheating of the liquid dining distillation at 109°C [2],... 

Though the ozonide appeared stable to small-scale high-vacuum distillation, the residue exploded violently at 130°C. 

Most studies of micellar effects upon rates or products of organic reactions have been made with very low concentrations of reactants, and this small scale of work is not very encouraging for the synthetic organic chemist. An additional disadvantage is that surfactants complicate product separation by extraction or distillation, and to date most studies in this general area have been exploratory and have been aimed at solving these problems. 

Over a three-year period at Rheinau, 1922-1925, Bergius and his assistants tested more than 200 different kinds of coal. Starting from a relatively small scale, they eventually hydrogenated coal in quantities as large as 1,000 kg (1 ton). A typical reaction run contained 100 kg of coal mixed with 40 kg of heavy oil, 5 kg of hydrogen gas, and 5 kg of ferric oxide to remove any sulfur present in the coal. The reaction yielded 20 kg of gas and about 128 kg of oil and solids. Distillation of the oil produced 20 kg of gasoline. (14)... 

Other factors important to the choice of catalyst are its stability under the reaction conditions (see Section 1.1) and its removal from the organic phase at the end of the reaction. Ideally, the catalyst should be sufficiently hydrophilic to be washed from the product by water, but any catalyst having this property has, by implication, a lower lipophilicity and lower catalytic effect. Where the product is volatile, it can be separated from the catalyst and isolated by fractional distillation of the organic phase or, alternatively, the catalyst can be precipitated from the concentrated organic phase by the addition of a non-polar solvent, such as diethyl ether, and removed by filtration. On a small scale, the catalyst can be separated efficiently by direct chromatography of the organic phase from, for example, silica. This procedure is, however,... 

The IR, NMR, and NMR spectra of this material are identical with those for distilled geranyl chloride (bp 49-51 C at 0.2 mm). Distillation on a small scale significantly reduces the yield, and there is no improvement in the yield of the phosphorylation reaction using distilled material. A synthesis of geranyl chloride was reported earlier in this series. We find, however, that the procedure of Corey, Kim, and Takeda is more convenient. 

The social component which is also very important for sustainability of a production of spirits is fulfilled too the production of fruit brandy, cacha a, tequila, rum, etc. is a very important basis of existence or additional earning for small-scale agricultural producers. These producers either directly sell their distillates as spirit drinks or they offer them to bigger distilleries for mass marketing. 

Cold-Water Process. The cold-water bitumen separation process has been developed to the point of small-scale continuous pilot plants. The process uses a combination of cold water and solvent. The first step usually involves disintegration of the tar sand charge, which is mixed with water, diluent, and reagents. The diluent may be a petroleum distillate fraction such as kerosene and is added in a ca 1 1 weight ratio to the bitumen in the feed. The pH is maintained at 9-9.5 by addition of wetting agents and ca 0.77 kg of soda ash per ton of tar sand. The effluent is mixed with more water, and in a raked classifier the sand is settled from the bulk of the remaining mixture. The water and oil overflow the classifier and are passed to thickeners, where the oil is concentrated. Clay in the tar sand feed forms emulsions that are hard to break and are wasted with the underflow from the thickeners. 

Benzoyl peroxide [94-36-0J M 242.2, m 95 (dec). Dissolved in CHCI3 at room temperature and ppted by adding an equal volume of MeOH or pet ether. Similarly ppted from acetone by adding two volumes of distilled water. Has also been crystd from 50% MeOH, and from ethyl ether. Dried under vacuum at room temperature for 24h. Stored in a desiccator in the dark at 0°. When purifying in the absence of water it can be EXPLOSIVE and it should be done on a very small scale with adequate protection. Large amounts should be kept moist with water and stored in a refrigerator. [Kim et al. JOC 52 3691 1987]. 

The addition of equivalent quantities of a (dialkylamino)trifluoro-/l4-sulfane (see Section 8.4.) to a (dialkylamino)trimethylsilane results in the formation of a bis(dialkylamino)difluoro-/l4-sulfane.71 The dialkylamino moieties of the reactants can be different, resulting in the synthesis of unsymmetrical products. This class of compound is not stable to distillation and is generally utilized without prior purification. For small-scale fluorinations, the bis(dialkylamino)difluoro-/l4-sulfanes are generated in situ, for example, by the addition of one equivalent of commercial-grade DAST to a solution of an appropriate (dialkylamino)trimethylsilane at low temperature.72 73 Examples for the preparation of a bis(dialkylamino)difluoro-/l4-sulfane l71 and dif-luoro-/l4-sulfane 25,11 with different dialkylamino groups are given below. 

Preparation.—It is either from nitrate of potassa or nitrate of soda that this odd is always obtained for chemical purposes. When saltpetre is heated with sulphuric acid, it is decomposed an alkaline sulphate remains in the retort, whilst the more volatile nitrio acid distils over, and may he condensed in tho usual manner. In preparing nitric add on the small scale, equal weights of nitre and concentrated sulphuric add are placed in a glass retort, and carefully dis-... 

On a small scale methyl nitrate can be obtained by carefully distilling a mixture of methyl alcohol with nitric add containing urea nitrate [18] or with nitric-sulphuric acid mixture at 40 or 18°C [19]. 

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