Butyl chlorides

Butyl chloride reacts with ammonia to produce dibutyl amine, which is used to make ZnDBC accelerator. 

In organic synthesis, butyl chloride is used as a butylating agent as well as an industrial solvent. 

Normal butyl chloride boils at 78° and has the specific gravity 0.907 at 0°. 

—It has been shown recently that alkyl chlorides can be prepared from alcohols and hydrochloric add in the presence of water, provided zinc chloride is present. The metallic chloride probably acts as a catalytic agent and not as a dehydrating agent, as has been assumed in the past. During 

To 190 g. (2 moles) of cold concentrated hydrochloric add (sp. gr. 1.19) is added 272 g. (2 moles) of anhydrous zinc chloride. The mixture is kept cold to avoid loss of hydrogen chloride. To this solution, 74 g. of 71-butyl alcohol (1 mole) is added (Note 1). The mixture is then refluxed over a free flame for three and one-half to four hours (Note 2). After cooling, the upper layer is separated (Note 3) and placed in a distilling flask with an equal volume of concentrated sulfuric acid (Note 4). The side arm of the flask is closed and the neck is connected with a reflux condenser. After refluxing gently for one-half hour, the chloride is distilled. The distillate is washed with water, dried over calcium chloride, filtered, and distilled. The fraction boiling at 76-78° weighs 59-61 g. (64-66 per cent of the theoretical amount). 

The best results were obtained when the substances were used in the molecular ratio 1 of alcohol, 2 of hydrogen chloride as concentrated hydrochloric acid, and 2 of zinc chloride. 

5-mole alcohol run for nine hours to obtain the yield mentioned in the procedure. 

The zinc chloride may be recovered from the aqueous solution by evaporation until a syrupy residue is obtained. This may be used in the next run. 

This treatment with sulfuric acid is carried out in order to remove high-boiling impurities that are not easily separated by fractional distillation. 

Water content None 40 Methyl propyl ketone 77.0 

Errors in parentheses refer to the last figure quoted they are three standard deviations except where otherwise stated 

The results for t-butyl chloride demonstrate forcibly the difficulty of comparing ra parameters directly with rg, rf, or ra structures because the ra parameters do not have a clear physical significance. If, as in this case, the position of an atom close to the centre of mass contains most of the error in the r% structure, then ra bond lengths may be either too long e.g. C-C) or too short e.g. C-Cl). It should be pointed out that 0.46 A would not be considered a particularly small co-ordinate by many spectroscopists indeed, many co-ordinates in the principal axis system of acrolein are smaller than this, yet the ra structure of acrolein is apparently a good approximation to re. The errors in ra co-ordinates vary so much from molecule to molecule, and for different atoms in the same molecule, that a clear set of guidelines for interpretation of ra structures cannot yet be given. 

There is little doubt that for all but the simplest molecules the gas-phase molecular structure is most reliably determined by a simultaneous analysis of electron diffraction data and such rotational constants as are available, with attention given to the relative weights assigned to the two types of observation. The range of molecules studied to date (Appendix 1) is a convincing illustration of the scope of the method as well as the success of the theory. The principal area of uncertainty lies in estimation of Srt, the 

The author is extremely grateful to Professor K. Kuchitsu for supplying preprints of several articles in advance of publication. 

Some molecules for which precise interconversion of spectroscopic and electron diffraction data has been carried out. Results quoted by Kuchitsu which are still unpublished at the time of writing ate all given ref. 18. 

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After the butyl chloride fraction has been collected, change the receiver and continue the distillation untU the zinc chloride commences to crystallise. Allow to cool and stopper the flask. The anhydrous zinc chloride thus obtained may be used in another preparation and recovered repeatedly. This results in considerable economy when the preparation is conducted by a large number of students. 

Reflux a mixture of 68 g. of anhydrous zinc chloride (e.g., sticks), 40 ml. (47 -5 g.) of concentrated hydrochloric acid and 18-5 g. (23 ml.) of sec.-butyl alcohol (b.p. 99-100°) in the apparatus of Fig. 777, 25, 1 for 2 hours. Distil oflF the crude chloride untU the temperature rises to 100°. Separate the upper layer of the distillate, wash it successively with water, 5 per cent, sodium hydroxide solution and water dry with anhydrous calcium chloride. Distil through a short column or from a Claisen flask with fractionating side arm, and collect the fraction of b.p. 67-70° some high boiling point material remains in the flask. Redistil and collect the pure cc. butyl chloride at 67-69°. The yield is 15 g. 

In a 250 ml. separatory funnel place 25 g. of anhydrous feri.-butyl alcohol (b.p. 82-83°, m.p. 25°) (1) and 85 ml. of concentrated hydrochloric acid (2) and shake the mixture from time to time during 20 minutes. After each shaking, loosen the stopper to relieve any internal pressure. Allow the mixture to stand for a few minutes until the layers have separated sharply draw off and discard the lower acid layer. Wash the halide with 20 ml. of 5 per cent, sodium bicarbonate solution and then with 20 ml. of water. Dry the preparation with 5 g. of anhydrous calcium chloride or anhydrous calcium, sulphate. Decant the dried liquid through a funnel supporting a fluted Alter paper or a small plug of cotton wool into a 100 ml. distilling flask, add 2-3 chips of porous porcelain, and distil. Collect the fraction boiling at 49-51°. The yield of feri.-butyl chloride is 28 g. 

Alternatively, use the equivalent amount of n-butyl chloride and prepare the Grignard reagent as for aec.-biltyl magnesium chloride. 

In an alternative procedure 26 g. of anhydrous ferric chloride replace the aluniiniuni chloride, the mixture is cooled to 10°, and the 50 g. of tert.-butyl chloride is added. The mixture is slowly warmed to 25° and maintained at this temperature until no more hydrogen chloride is evolved. The reaction mixture is then washed with dilute hydrochloric acid and with water, dried and fractionally distilled. The yield of tert.-butyl benzene, b.p. 167- 170°, is 60 g. 

About 20 g. of n-butyl chloride, b.p. 76-80°, may be recovered by carefully rofractioiiating the distillate that passes over below 86°. 

The reason for this is that reaction (i) is usually much slower than (ii) and (iii) so that the main reaction appears to be (Iv) (compare the preparation of tertiary butyl chloride from tertiary butyl alcohol and concentrated hydrochloric acid, Section 111,33). If the reaction is carried out in the presence of P3rridine, the latter combines with the hydrogen chloride as it is formed, thus preventing reactions (ii) and (iii), and a good yield of the ester is generally obtained. The differentiation between primary, secondary and tertiary alcohols with the aid of the Lucas reagent is described in Section III,27,(vii). 

Draw the mechanism of the imaginary reverse reaction, the formation of t-butyl chloride from the alcohol. 

Apparatus and procedure Closely similar to the preparation of tert.-Ci,H3MgCl, cyclohexyl-MgCl and cyclopentyl-MgCl (see Exp. 2). The yield (estimated from the results obtained from reactions with this reagent) is at least 90%. Here, too, it is essential to use M-butyl chloride which is free from butyl alcohol. 

The crude tosylate obtained after evaporation of the diethyl ether was dissolved In 150 ml of THF. After addition of 1 g of CuBr the solution was cooled to -10°C and a solution of tert.-butylmagnesium chloride in 250 ml of THF, prepared from 0.40 mol of -butyl chloride and magnesium (see Chapter II, Exp. 4) was added... 

FIGURE 4 6 The mechanism of formation of tert butyl chloride from tert butyl al cohol and hydrogen chio ride... 

FIGURE 4 11 Combi nation of tert butyl cation and chloride anion to give tert butyl chloride In phase overlap between a vacant p orbital of (CHbIbC and a filled p orbital of Cr gives a C—Cl (T bond... 

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