Dichloride Solution

Burger, A. Delay, and F. Mazenod, Helv. Chim. Acta, 51, 2106 (1974). 

Submitted by MARTIN POMERANTZ, GERALD L. COMBS JR., and N. L. DASSANAYAKE  

The authors wish to thank the Robert A. Welch Foundation and the Organized Research Fund of UTA for support of this work. 

A Textbook of Qualitative Inorganic Analysis, 3rd ed., Longman s, London, 1961, p. 399. 

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The solid appears to be a mixture of the complexes CH,COOH.BF, and 2CH COOH.BF,. The latter appears to be a liquid and is alone soluble in ethylene dichloride the former is a solid. The solid moiioocetic acid complex is obtained by saturating an ethylene dichloride solution of acetic acid with boron trifluoride, filtering and washing the precipitate with the solvent it is hygroscopic and should be protected from moisture. It may be used as required 0-75 mol is employed with 0-26 mol of ketone and 0 6 mol of anhydride. 

P-o 3-ketal in 130 ml of glacial acetic acid and 130 ml of water is maintained at 80° for 30 min, poured onto ice, made alkaline with sodium hydroxide and extracted with methylene dichlofide. The extracts are washed once with water, dried over magnesium sulfate, filtered, and evaporated to a residue. A solution of this residue in 240 ml of pyridine and 120 ml of acetic anhydride is kept at room temperature for 1.25 hr and then poured into hydrochloric acid-ice water. The mixture is extracted with methylene dichloride and the methylene dichloride solution is washed until neutral, dried over magnesium sulfate and filtered. The filtrate is evaporated to dryness to yield 13 g. Crystallization from aqueous acetone yields 11.8 g (92%) mp 251-255° [ ]d —1° (dioxane). 

In the 19-nor series, the reaction with NOF is more complex and there is isolated in addition to the fluoro nitrimine corresponding to (31) a 20% yield of the nitroso dimer (34), which dissolves in methanol-methylene dichloride solution to give the pure blue color characteristic of the monomer (35). The latter then isomerizes to the oxime (36). 

Apparently the role of methanol is to intercept unstable species which otherwise tend to polymerize or rearrange. The methoxy peroxide (72) can be isolated in crystalline form if desired, but it is preferable to treat the methylene dichloride solution at 0° with zinc dust and acetic acid until the mixture shows a negative potassium iodide test. The resulting crude seco-aldehyde (73) is then cyclized to (74) by stirring with neutral alumina in benzene at room temperature for 3 hr. ° Wechter has recently reported a number of transformations of a 5yS-hydroxy-6yS-formyl-B-norpregnane prepared in 8% yield by photolysis and hydrolysis of a 5a-hydroxy-6 -azidopregnane. 

The iso-LSD salt can be converted back into the base by the addibon of methanolic KOH or potassium methoxide to the mother liquor. The resulting mixture should be added to a separatory funnel containing salt solution and ethylene dichloride. The LSD base is extracted into the ethylene dichloride layer (the lower layer). The lower layer is removed and fresh ethylene dichloride used to extract the last traces of LSD base from the salt water-base mixture. The ethylene dichloride extracts are combined, dried with MgSO, decolorized and filtered through diatomaceous earth as earlier. I he resulting ethylene dichloride solution may be combined with the chloroform solutions of iso-LSD which eluted from the chromatographic column. The combined solution may be evaporated to dryness under reduced pressure. 

The methanolic solution is poured into a separatory funnel containing salt water solution and ethylene dichloride. The salt water layer is repeatedly extracted with ethylene dichloride to separate the LSD base from the w ater-base mixture. The ethylene dichloride extracts are combined, dried with MgS04, decolorized and filtered. The ethylene dichloride solution is then evaporated to dryness under reduced pressure. 

A ubiquitous co-catalyst is water. This can be effective in extremely small quantities, as was first shown by Evans and Meadows [18] for the polymerisation of isobutene by boron fluoride at low temperatures, although they could give no quantitative estimate of the amount of water required to co-catalyse this reaction. Later [11, 13] it was shown that in methylene dichloride solution at temperatures below about -60° a few micromoles of water are sufficient to polymerise completely some decimoles of isobutene in the presence of millimolar quantities of titanium tetrachloride. With stannic chloride at -78° the maximum reaction rate is obtained with quantities of water equivalent to that of stannic chloride [31]. As far as aluminium chloride is concerned, there is no rigorous proof that it does require a co-catalyst in order to polymerise isobutene. However, the need for a co-catalyst in isomerisations and alkylations catalysed by aluminium bromide (which is more active than the chloride) has been proved [34-37], so that there is little doubt that even the polymerisations carried out by Kennedy and Thomas with aluminium chloride (see Section 5, iii, (a)) under fairly rigorous conditions depended critically on the presence of a co-catalyst - though whether this was water, or hydrogen chloride, or some other substance, cannot be decided at present. 

Kinetic studies in methylene dichloride solution. The most detailed kinetic study was carried out by Plesch and his collaborators with methylene dichloride as solvent and water as co-catalyst, but only a preliminary summary of the results has been published [80] much of the information given below is taken from material which is being submitted for publication during 1963. 

Since the determination of absolute rate constants is one of the most urgent problems in cationic polymerization, and the styrene-perchloric acid system seemed to be so clean and simple, Gandini and Plesch set out first to check Pepper and Reilly s results by determining spectroscopically the concentration of carbonium ions during polymerization, and they intended then to extend the method to other monomers. However, their findings were not as expected. A comparison of spectroscopic and conductivity measurements with rate measurements in an adiabatic calorimeter showed [4] that in methylene dichloride solution ... 

With sulphuric acid, also in methylene dichloride solution, no carbonium ions were visible throughout the polymerization, and none were formed at the end of the reaction. 

With ethylene oxide the situation is complicated. Worsfold and Eastham [63] showed that under anhydrous conditions in ethylene dichloride solution boron fluoride reacts slowly with the monomer to form a co-catalyst and that after the induction period during which this occurs the polymerization proceeds smoothly and that the induction period can be eliminated if water, equivalent to the boron fluoride, is added to the system. 

We have shown [1, 2] that, in the polymerisation of styrene by perchloric acid under the conditions reported here, the initiation reaction does not produce carbonium ions and that the monomer is polymerised by non-ionic chain carriers. Since the most likely nonionic reaction product formed from perchloric acid and styrene is the ester 1-phenylethyl perchlorate we attempted its preparation in order to try it as catalyst for the polymerisation of styrene. However, we found this ester to be unstable in methylene dichloride solution. It forms styrene oligomers, polystyryl ions, and perchloric acid, and the preparative technique and the mechanism of the reactions involved will be discussed in a paper dealing with the spectroscopic behaviour of polymerising and polymerised systems. 

For the system styrene-perchloric acid-methylene dichloride we can now write the following reactions on the basis of what has just been discussed and of our findings on the state of perchloric acid in methylene dichloride solutions [9] ... 

Bywater and Worsfold s [25] and our own [26] results show that for the SD ions the optical density and conductivity are linearly related (methylene dichloride solution, concentration 10"5-10"3 M) showing that under these conditions ion-pairing is unimportant. 

When H2S is passed through palladium dichloride solution, it yields a brown-black precipitate of palladium monosulfide, PdS. 

CS-methylene dichloride solutions dropped into heated cup 20-m3 chamber group exposures—total body no motivation—as for study 1 0.40-0.90 21 0.7 0.6... 

From studies of the initial rates of the ethylene oxide-stannic chloride reaction in ethylene dichloride solution, Worsfold and Eastham (12) concluded that the rate was expressed rather closely by the equations. 

C to 229.8°C (corrected) recrystallized from a benzene-methanol mixture, [a]D25 = +76.5°C (1% in chloroform), was prepared by treating 17p-acetoxy-4-androsteno[2,3-d] isoxazole with maleic anhydride and hydrogen peroxide in methylene dichloride solution. 

A solution of 50 g. (0.228 mol) of dimethyltin dichloride in 750 ml. of anhydrous ether in a 3-1., three-necked flask equipped with a mechanical stirrer, a reflux condenser, and a 1-1. dropping funnel is cooled to —50°. A solution of diazomethane in ether (0.35 mol of CH2N2 in 500 ml.) at —5° is added slowly with vigorous stirring. The diazomethane solution is decolorized immediately on contact with the dimethyltin dichloride solution, and evolution of nitrogen is observed. After the addition is complete, the... 

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