Derivatives of Allvlic Chlorides Metathesis Reactions of Methallyl Chloride M. TAMELE, C. J. OTT, K. E. MARPLE, AND G. HEARNE c
Shell Development Company, Emeryville, Calif.
F""
several years the preparation of allylic chlorides and their derivatives has
*
increases the reactivity of the chlorine atom. This is confirmed by the observation that 1-chloro-2-methyl-2-butene is more reactive than crotyl chloride. However, the influence of a methyl group in the beta position is apparently less than that of a methyl group in the gamma position; e. g., methallyl chloride is less reactive than crotyl chloride. The velocity of reaction with sodium alcoholate in anhydrous alcohol was also determined for the various chlorides. Methallyl chloride has about the same reactivity as allyl chloride a t 35" C., but slightly less a t 50" C. It is less reactive than crotyl chloride. and the latter is less reactive than l-chloro-2-methyl-2-butene.
Methallyl chloride as a typical allylic chloride is extremely reactive and can be employed for the synthesis of a large number of derivatives by metathesis. Methallyl alcohol is produced on a semicommercial scale in good yield by hydrolysis under pressure. A number of methallyl ethers have been obtained by reaction with alcohols and a variety of methallyl-substituted amines by ammonolysis. The chloride has also been reacted with metals and metal salts to form characteristic derivatives. Since methallyl chloride has been available commercially for only a short time, many of these products have not previously been prepared.
been studied in considerable detail in these laboratories. Previous publications (4, 8) described the development of some of the chlorides from little-known laboratory curiosities to valuable chemical intermediates, which in some cases are available in commercial quantities. Because the allylic chlorides possess a reactive chlorine atom and an olefin linkage, they can be employed in a large number of syntheses, many of which have been tried for the first time in these laboratories. I n this and subsequent publications, these reactions will be described in a n effort to present a more concise picture than can be gathered from the various patents on the subject. The present paper describes some of the derivatives which can be made available by reacting the chlorine atom in methallyl chloride. The products from reaction of the double bond will be described in the second paper of this series. As was pointed out in a previous paper (4, methallyl chloride (isobutenyl chloride) was originally prepared by Sheshukov (19) in 1884,but i t remained relatively unknown until recent work on the chorination of isobutylene renewed interest in it. The commerical product contains approximately 4 per cent of P,P-dirnethylvinyl chloride (CHs)AC=CHCl, which is formed simultaneously in the isobutylene chlorination. The chlorine in this isomer is extremely inert, so that if commercial methallyl chloride is used in the reactions described in this paper, the &@-dimethylvinyl chloride is recovered unchanged. Hence its presence is of little importance. This is not true, however, for reactions involving the double bond.
R~~~~~~~~~of Methallyl Chloride ~
~to Other l
Allylic Chlorides It has long been known that the allylic halides are among the most reactive in metathesis. This has been established by various methods, but apparently the most reliable is by comparison of the velocity of reaction between various halides and potassium iodide (6, IS). This method was employed for determining the position of methallyl chloride with reference to other allylic chlorides. Under identical conditions, reaction was more rapid with methallyl than with allyl chloride, but less rapid than with crotyl chloride. Thus i t appears that the introduotion of a methyl group into allyl chloride
Hydrolysis Methallyl chloride was first hydrolyzed to methallyl alcohol (isobutenol) by Sheshukov (19), who refluxed the chloride with aqueous potassium carbonate for 30 hours. The hydrolysis was also tried by Pogorshelski (16) and more recently by Schales (18), but they contributed little additional information on this reaction. The rate of hydrolysis can be greatly increased by operating under pressure a t temperatures above the boiling point of the chloride (91). The time required depends upon the temperature, the alkalinity of the hydrolysis medium, and the efficiency of agitation. At 116" C. the chloride has been completely reacted in less than 15 minutes using 10 per cent aqueous sodium hydroxide as hydrolyzate. At temperatures of about 200" C. the hydrolysis proceeds so rapidly that points of local acidity may develop in the reaction mixture unless it is rapidly stirred. Various neutralizing agents have been tried, such as sodium hydroxide, carbonate, and and~calcium hydroxide-and car~ ~ bicarbonate i ~ bonate. The hydrolysis using sodium hydroxide is more rapid than with calcium hvdroxide. The nature of thk hydrolysis product depends upon the reaction conditions. If the mixture becomes acid either through inefficient mixing or lack of a suitable neutralizing agent, isobutyraldehyde is formed. When a suspension of calcium carbonate in water was used a t 140-180" C., all of the alcohol produced was converted to aldehyde. This is not surprising, since Sheshukov (19) was able to effect the rearrangement merely by warming methallyl alcohol with dilute aqueous sulfuric acid. When the hydrolyzing mixture develops points of local acidity through inefficient agitation, a 115
I16
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 33, No. 1
TABLEI. PKPSICAL CONSTANTS OF METHALLYL DERIVATIVES Compound
Formula
Boiling Point, C.
Sp. Gr.. d’:
Refractive Index,
114.49 134.34 84,8-86.8 103.8-104.2 129.8-130.8 114.9-115.9 78.8 148-149 83-85 (15 mm.) 100-106 (10 mm.) 91,8-94.8 (10 mm.) 154-155.5 197-198 92.0-92.5 25-30 (3-5 mm.) 172.8-173.0 92.4-92.6 136.2-136.4 69 (20 mm.) 114.3 129 126 208-210 119-121 140-143 175-1 76
0.8515 0.8163 0.8151 0.7748 0.7930 0.8167 0.782 0.799 0.8256
1.4256 1.4276 1.4067 1.4015 1,4136 1.4236 1.431 1.446 1.457
n’+? -
Methallyl alcohol Dimethall 1 ether E t h y l metxall 1 ether Is0 ropy1 metgaily1 ether sec-%utyl methallyl ether Allyl methallyl ether Methallylamine Dimethallylamine Trimethallylamine
M ethallylphenylamine
CHz=C(CHa)CHzNHCsH,
N,N’-Dimethallylethylenediamine
[CHz=C(CHs)CHzNHCHz]z
Crotylmethallylamine Crotyldimethallylamine Methallyl bromide Methallyl iodide Dimethallyl sulfide Methallyl merca t a n k e t h a l l y l pyani& Methallyl isothiocyanate Dimethallvl 4-Methyl-4-pentene-2-01 2,4-Dimethy1-4-penten-2-01 2 4-Dimethyl-1-hepten-4-01 2LMeth yl-1-heptene 2,6-Dimethyl-l-heptene Phenylmethallyl
complex mixture of products may result from the subsequent reactions of isobutyraldehyde with alkali. Isobutyric acid, octaglycol (2,2,4-trimethyl-1,3-pentanediol),and isobutyl alcohol have been isolated in substantial quantities. These are known to be formed by the action of alkali on isobutyraldehyde ( 2 1 ) . I n practice it has not proved difficult to avoid acidity during the hydrolysis, and consequently these side reactions are easily eliminated. The principal by-product from the hydrolysis under neutral and alkaline conditions is dimethallyl ether [CHpC(CHa)CH,],O. It is always formed a t least to a small extent (around 5 per cent) in the hydrolysis, but by changing the reaction conditions i t may be made the principal product. The ether was not discovered by earlier workers, and even in some of the preliminary experiments in this investigation, i t was not observed probably because i t forms an azeotrope with methallyl alcohol which boils almost exactly a t the boiling point of the pure alcohol (Tables I and 11). Dimethallyl ether is formed by reaction of equimolecular quantities of chloride, alcohol, and alkali : CHFC (CHs)CHzCl
+ NaOH---t + CHF=C(CH~)CH~OH [CHF==C(CHS)CHZ]~O + NaCl + HzO
It is not formed by elimination of one mole of water from two alcohol molecules, for the alcohol is quite stable in neutral and alkaline solutions a t the temperature employed in the hydrolysis. The ratio between the hydrolysis and alcoholysis which occur simultaneously depends upon the ratio of water to alcohol in the hydrolyzate. Actually the percentage of ether formed is slightly higher than would be predicted from the mole ratio of alcohol to water. This can be explained in part by the fact that the hydrolysis mixture is not homogeneous and the mutual solubility of alcohol and chloride is greater than that of water and chloride. The best yields of alcohol have been achieved by hydrolyzing in the presence of a large excess of water. The alkalinity of the hydrolyzing solution is another factor influencing the relative proportions of alcohol and ether. I n strongly alkaline solutions, the percentage of ether formed is larger than in an approximately neutral medium. A complete explanation of this difference would require a more detailed kinetic study than has been given in the present investigation. It should be noted however that, as pointed out by
...... ......
...... ...... ...... ......
...... ......
......
1.4862
0.8836 0.9137 0.844 0.9926 0.7487
1.4862 1.4872 1.4202 1.5220
...... ...... ...... ......
......
......
......
......
...... ...... ......
......
......
Hughes ( I d ) , the allylic chlorides are capable of reacting readily by two distinct mechanisms-i. e., a unimolecular reaction with the solvent (alcohol or water) and a bimolecular replacement of the chlorine atom by a hydroxyl or an alkoxy1 group. The former predominates when the chloride is hydrolyzed under approximately neutral conditions, but the latter may be the principal reaction under alkaline conditions where the concentration of hydroxide and alkoxy ions is high. Both of the reactions lead to the formation of alcohol and ether, but the ratio may be quite different. The high percentage of ether formed under more alkaline conditions indicates that the bimolecular replacement reaction favors ether formation more than the solvolytic reaction. Since both acid and alkali are detrimental to the yield of alcohol, it is important to maintain the pH of the hydrolyzing solution within narrow limits. If this is done, methallyl alcohol can be prepared in a yield of about 90 mole per cent. TABLE11. AZEOTROPIC DATAON METHALLYL DERIVATIYIOS Compn. of Azeotrope, Wt. % Mrthallyl alcohol 69.6, water 40.4 Dimethallyl ether 69.0, water 31.0 Dimethallyl ether 81.3, methallyl alcohol 18.7 Dimethallyl ether 46.06, methallyl alcohol 26.73, water 27-21 Methallylamine 94, water 6 ,
Boiling Point, C. 92.5
-Compn. of Phases. W t . %-Upper layer Lower layer
92.5 114.06 90.0 78 4
Ether 63.7 Ether 0 , l alcohol 3’3.5, alcohol b . 1 water 2 , s water 90.8 Homogeneous
It is of interest to note that, although one of the principal difficulties in the hydrolysis of some saturated chlorides is the elimination of hydrogen chloride to form an olefin, this is not observed to any appreciable extent in the hydrolysis of the allylic chlorides (22). Methallyl chloride has the added advantage that an elimination of hydrogen chloride of this type is structurally impossible.
Etherification The first methallyl ether was prepared by Sheshukov (19) who treated the chloride with sodium ethylate, as well as with anhydrous alcoholic potassium hydroxide, and obtained
INDUSTRIAL AND ENGINEERING CHEMISTRY
January, 1941
4
ethyl methallyl ether. Methallyl chloride, however, is so reactive that many of its ethers can be synthesized merely by heating it with the alcohol and concentrated aqueous sodium hydroxide (9). The rate of reaction varies greatly with the alcohol employed. The allylic alcohols are very reactive, as was indicated by the formation of dimethallyl ether during the hydrolysis of methallyl chloride even in the presence of a large excess of water. The reaction of methallyl chloride with methallyl alcohol in the presence of 50 per cent aqueous sodium hydroxide occurs a t a much lower temperature than hydrolysis. At 90' C. it proceeds rapidly enough t o maintain this temperature by the heat of reaction. Dimethallyl ether is formed in a yield of 90 mole per cent with only a small amount of alcohol formed by hydrolysis. Some of the ethers which can be prepared from methallyl chloride, concentrated aqueous sodium hydroxide, and alcohol are methyl methallyl, ethyl methallyl, isopropyl methallyl, a n d phenyl methallyl ether. (The physical properties of the ethers are shown in Table I.) Secondary butyl methallyl ether can also be synthesized by this method, but the reaction is slow. It can be obtained readily using anhydrous secbutyl alcoholate prepared from sodium and the alcohol. Methyl methallyl ether was doubtless obtained by Schales (18) when he treated methallyl chloride with methyl alcoholic potassium hydroxide, but he did not isolate it. Barta, Miller, and A d a m ( 2 ) prepared the phenyl methallyl ether from phenol, methallyl chloride, and sodium carbonate in acetone solution. This was rearranged to methallyl phenol, which was hydrogenated to isobutyl phenol. The method was used for introducing the isobutyl group into other phenols as well. It is noteworthy that no tert-butylphenols are formed as is the case in other alkylation processes where isobutyl derivatives might be expected. The rate of etherification of methallyl chloride with an alcohol apparently depends upon the ability of the latter to dissociate into hydrogen ions and alkoxy ions. The alcohols which are known to be most highly ionized show the greatest reactivity. For example, Barta, Miller, and Adams (2) prepared the phenyl methallyl ether from phenol, methallyl chloride, and sodium ethylate. The difference in reaction rate cannot be explained on the basis of the physical properties of the alcohols, for the solubilities of sec-butyl alcohol and methallyl alcohol in water are of the same order (12.5 and 14.7 per .cent, respectively, a t 20' (3.). It thus appears that etherification involves a reaction between the organic chloride and alkoxy ions. When the chloride is etherified with a mixture of an alcohol and a base, hydroxide ions are also present, and the ratio between these and alkoxy ions depends upon the equilibrium in the reaction: ROH
+ OH-
OR-
+ H10
The ratio between etherification and hydrolysis depends to a great extent upon the relative amounts of alkoxy and hydroxide ions in contact with the organic chloride: Hydrolysis: CH-C(CHs)CHzCl
+ OH-
--f
CHz=C(CHs)CH,OH
+ C1-
Etherification: CHFC(CH3)CHzCl
+ OR-
----f
CHz=C(CHs)CHzOR
+ C1-
The more highly dissociated alcohols have a more favorable ratio of alkoxy to hydroxide ions, and consequently methallyl chloride forms ethers of these alcohols in good yield even in the presence of water. One of the best known methods for preparing ethers is by an acid-catalyzed dehydration of the alcohol. However, this cannot be used for preparing methallyl ethers since the alcohol is rearranged to aldehyde under acid conditions as noted above.
117
Ea terification Pogorshelski (16) reacted methallyl chloride with potassium acetate and obtained methallyl acetate. This reaction was not studied further because the synthesis of the methallyl esters starting from the alcohol appeared to be superior.
Ammonolysis Methallyl chloride reacts readily with ammonia and amines to form methallyl amines (23). One convenient method of preparation is to treat the chloride with an excess of 28 per cent aqueous ammonia in an autoclave under pressure. At 90" C. the reaction is extremely rapid and reaches completion in less than 2 minutes. With a mole ratio of chloride to ammonia of 1 to 10, the methallyl amines have been obtained in the following yields based on the chloride applied: primary 56 per cent, secondary 26, tertiary 8 , and quaternary 5. The high percentage of secondary was surprising in view of the large excess of ammonia employed; therefore some tests were undertaken to find an explanation. The amount of secondary was not increased by heating the reaction mixture for a longer time at the reaction temperature. A sample of primary amine was heated for 30 minutes with 28 per cent aqueous ammonia, both in the presence and absence of ammonium chloride. No secondary amine was formed. It was concluded, therefore, that the secondary amine is not formed by elimination of ammonia from two molecules of primary amine but is formed instead by reaction of the primary amine with the unsaturated chloride. The ratio between the quantities of primary and secondary depends upon the relative velocities of the two competing reactions: RC1
+ NHa +RNHaCl (+"8)
RC1
+ RNHz
RSNHzCl
+ NHdCl RzNH + NH,C1
RNHi
(+"a)
(1) (2)
The large amount of secondary shows that reaction 2 is much more rapid than 1, and that primary methallylamine is more reactive than ammonia. A further indication of the greater reactivity of the primary amine is the fact that i t is slightly more alkaline than ammonia. The pH of a 1M methallylamine solution a t room temperature is 11.90, whereas an ammonia solution of the same concentration has a pH of 11.74 as measured under identical conditions with a glass electrode. The addition of hydrogen chloride to a solution of the primary amine and ammonia would be expected to form amine hydrochloride preferentially t o ammonium chloride. Consequently, i t would be predicted that the ammonolysis of methallyl chloride in the presence of some hydrogen chloride (as ammonium chloride) would produce the primary amine in a more favorable ratio. This was confirmed by reacting methallyl chloride with ammonia and ammonium chloride in mole ratios of 1 t o 2 to 3. The yield of primary amine was 58 per cent, of secondary, 10 per cent based on the chloride applied. This is a more favorable ratio of primary to secondary than was obtained with a much larger excess of ammonia. There was a poor product balance, which may indicate the formation of some isobutyraldehyde. When ammonium carbonate was used instead of the chloride, some methallyl alcohol was isolated, and this is known to rearrange to aldehyde easily under acid conditions. The influence of temperature and solvent on the ammonolysis was also determined, using a mole ratio of organic chloride to ammonia of 1 to 10. The ratio between primary and secondary amine was not greatly altered, but there was a large variation in the rate of reaction. It was very rapid in aqueous and anhydrous ammonia, but was progressively slower in a 50 per cent water-50 per cent ethyl alcohol mix-
118
INDUSTRIAL AND ENGINEERING CHEMISTRY
ture, in anhydrous ethyl alcohol, and in benzene. The rate apparently depends upon the polarity of the solvent. Methallyl chloride reacts readily with primary and secondary amines to formsecondary and tertiary methallyl-substituted amines. Aniline forms methallylphenylamine in a yield of 84 mole per cent. Ethylenediamine is converted into N,N'-dimethallylethylenediamine. Crotylamine reacts to form crotylmethallylamine and crotyldimethallylamine. Dimethallylamine is easily converted to trimethallylamine. Diphenylamine, however, reacts with methallyl chloride only slowly if a t all. The reaction of dimethylaniline with methallyl chloride was studied briefly to determine the feasibility of preparing methallyl-substituted quaternary bases. The materials could be reacted by warming them together either in the presence or absence of solvents, but by-products were formed in all cases. Some of the quaternary salt was isolated and dried i n vacuo, but it was found t o decompose easily.
Reaction with Metal Salts A wide variety of methallyl compounds can be prepared by reaction of methallyl chloride with metal salts (IO). METHALLYL BROMIDEwas synthesized from the chloride and sodium bromide in anhydrous acetone solution by heating under reflux for 5 hours. It had previously been prepared from zinc and 1,2,3-tribromoisobutane (16). METHALLYL IODIDE was prepared from the chloride and sodium iodide in anhydrous methyl ethyl ketone by refluxing for 3 hours. It is unstable and may decompose violently a t elevated temperatures or even on prolonged storage a t room temperatures; consequently, adequate precautions should be taken when working with this compound. DIMETHALLYL SULFIDEwas synthesized by heating the chloride and sodium sulfide (as NazS.9Hz0) a t 120" C. under pressure. DIMETHALLYL DISULFIDEwas synthesized in a similar manner using sodium disulfide prepared from sulfur and sodium sulfide. Both the sulfide and disulfide are valuable as a fly repellent or fumigant (34). METHALLYL MERCAPTAN was prepared by heating the chloride with aqueous or alcoholic sodium hydrosulfide. METHALLYL CYANIDE was obtained from methallyl chloride and cuprous cyanide or sodium cyanide. The former gives a n apparently pure product boiling a t 136.2-136.4' C., but the latter yields a mixture boiling somewhat higher (138.C139.5' C.). This indicates that some methallyl cyanide has rearranged to P,P-dimethyl acrylonitrile [(CH3)2C==CH-CN], the boiling point of which is listed as 140-142" C. (14). The allyl halides are known to form crotyl nitrile (CH,-CH= CH-CN) instead of allyl cyanide (CH,--CH-CHzCN) on treatment with sodium or potassium cyanide ( I ) . The reaction of methallyl chloride with cuprous cyanide is apparently autocatalytic. The best method for preparing the cyanide was to add the chloride in small batches to the cuprous cyanide in nitrobenzene solution. At temperatures of the order of 115-120" C. the reaction could not be initiated, but a t 125-130' C. it was vigorous. METHALLYL ISOTHIOCYANATE was prepared by Bruson and Eastes (8) by heating methallyl chloride with sodium thiocyanate in methyl alcohol solution. They converted i t to 5,5-dimethyl-2-mercaptothiazolineby treatment with sulfuric acid. METHALLYL-SUBSTITUTED BARBITURIC ACIDS were prepared by Schales (18) and also Doran and Shonle (6) from methallyl chloride, a mono-substituted barbituric acid, and caustic. The latter investigators also synthesized many of them by reacting the chloride with malonic ester and sodium, followed by condensation with urea. Some methallyl thiobarbiturates have also been synthesized (10).
Vol. 33, No. 1
Reaction with Metals Methallyl chloride was converted t o dimethallyl (2,5dimethyl 1,5-hexadiene) by Przybytek ( I 7 ) by heating it with sodium in anhydrous ether for 2-3 months. Schales (18) subsequently found that the reaction was much more rapid when magnesium was used instead of sodium. The first investigator obtained a product boiling a t 113-114" C., whereas the latter reported 136-137" C. The reaction was tried in these laboratories prior to the publication of Schales but under approximately the same conditions. A similar rapid exothermic reaction was observed, but the diolefin produced (90 mole per cent yield) boiled a t 114.3' C., in agreement with Przybytek (17) and other investigators (7). No material boiling a t 136-137" C. was observed. The primary reaction of methallyl chloride with magnesium is to form the Grignard reagent. Coupling between this and another molecule of methallyl chloride forms the dimethallyl: CH*=C(CH,)CHzCl CHPC(CHa)CH&l
+ CHz=C(CH3)CH2MgCl + Mg CHFC(CHa)CHzMgCl[CHz=C(CHdCHzlz
+ MgCL
The coupling can be prevented by adding the chloride to magnesium and anhydrous ether slowly, using a large excess of magnesium and ether. Methallyl magnesium chloride has actually been prepared in a yield of 90 mole per cent as determined by titration and by measurement of the isobutylene produced on hydrolysis of a Bample. However, this can be obtained only by careful operation, since the coupling is difficult to avoid. Methallyl magnesium chloride prepared in this manner has been reacted with acetaldehyde to form a secondary alcohol, 4-methyl-4-penten-2-01, CH2=C(CH3)CH2CHOHCH3,in a 65 per cent yield. The Barbier synthesis has been successfully applied to utilize the methallyl magnesium chloride as soon as formed. Thus acetone, methallyl chloride, and magnesium have been reacted in anhydrous ether to form 2,4-dimethyl-4-penten2-01, CH-C (CH,)CH&(CH,)OHCH,, in a yield of 59 mole per cent. Dimethallyl was obtained simultaneously in a 37 mole per cent yield. \;tThen methyl propyl ketone was used instead of acetone, the alcohol formed was 2,4-dimethyl-l-hepten4-01, CH+2(CH,)CH&(CHs)OHCHzCH&Ha. Methallyl chloride reacts readily with other Grignard reagents as would be expected. n-Butyl magnesium chloride formed 2-methyl-1-heptene in a yield of 83 mole per cent. Isoamyl magnesium chloride and methallyl chloride formed 2,6-dimethyl-l-heptene and phenyl magnesium bromide was converted into phenyl methallyl, CaHjCHzC(CH3)=CHZ, in a similar manner. Methyl magnesium bromide was reacted with methallyl chloride in diisopropyl ether solution to form 2-methyl-1-butene, Diethyl ether could not be used as the solvent in this preparation because it boils too close to the olefin t o permit satisfactory separation.
Relative Reactivity of Allylic Chlorides Samples of pure allyl chloride, methallyl chloride, crotyl chloride, and 1-chloro-2-methyl-2-butene boiling constantly within a fraction of a degree were prepared from the corresponding alcohol, phosphorus trichloride, and pyridine according to the method described by Juvala (13). The crotyl chloride boiled at 83.8' C.; d":, 0.9340; ng, 1.4356. The properties of the other chlorides were described in the previous publications (4, 8). For the reaction,
RCl
+ KI +RI + KCl
thick-walled test tubes 16 cm. long and 2.5 cm. in diameter were used as reaction vessels. Exactly 0.0002 mole of a standard solution of potassium iodide in acetone (5 cc.) was introduced into each tube, and a thin-walled bulb containing 0.001 mole of organic chloride was inserted along with several glass beads. (The molecular proportion of iodide t o organic chloride was 1 t o 5.)
INDUSTRIAL AND ENGINEERING CHEMISTRY
January, 1941
119
TABLE 111. RELATIVE REACTIVITIES OF ALLYLIC CHLORIDES Reaction with Sodium Ethylate a t 35O C.
Reaction with Potassium Iodide a t 20' C. Allyl chloride
Time, hr. %reacted k
Methallyl chloride
Time, hr. yo reacted
3.00 26.98 0.235
4.50 37.57 0.238
5.00 39.41 0.228
1.50 2.00 14.60 26.00 0.360 0.336
3.00 38.40 0.366
Av. k
Av. k
18.00 20.00 0.253
20.00 21.00 0.242
3.50 41.55 0.350
4.00 46.36 0.357
6.00 61.00 0.367
18.00 19.50 0.245
20.00 21.40 0.248
k
1.00 22.14 0.557
2.00 2.50 35.92 46.33 0.503 0.507
6.00 73.61 0.531
7.00 78.87 0.537
20.00 50.00 0.911
22.00 52.10 0.900
Av. k
3.00 48.83 0.513
k
0.50 1.00 18.13 30.15 0.885 0.805
Av. k
1.75 2.00 43.59 53.23 0.752 0.879 0.867
4tb
42.00 38.00 0.266
4.00 21.00 1.222
22.00 22.90 0.245
24.00 55.00 0.926
5.00 25.50 1.218
24.00 24.70 0.260
42.00 36.40 0.251
4.00 5.00 19.5 22.6 1.118 1.064
6.00 27.10 1.146
24.00 61.00 1.190
1.194 6.00 24.00 25.2 59.5 1.038 1.118
1.084 27.00 44.00 57.00 69.00 0.900 0.924
0.912 2.50 65.45
3.00 67.35 1.001 0.882
The tube was sealed and placed in a thermostat bath a t 20.0" C. * 0.05' for 30 minutes; the reaction was started by breaking the inner bulb. After a given period of time, the tube was removed from the thermostat and broken, and the contents were introduced into a flask containing ice and hydrochloric acid. The amount of unreacted potassium iodide was determined by titration with 0.003 M potassium iodate. The results are shown in Table I11 together with the velocity constant IC calculated from the equation 1 k = - log
24.00 23.80 0.231
0.248
0.535
Time,hr. %reacted
22.00 22.40 0.239 0.246
0.354
Time hr % re;cteb.
1-Chloro-%methyl2-butene
7.50 50.28 0.214
0.226
k
Crotyl chloride
6.00 7.00 43.08 49.72 0.214 0.226
Reaction with Sodium Ethylate a t 50.0' C.
5 -z 5(1-Z)
where b = concentration of potassium iodide, moles/liter 2 = fraction of potassium iodide which has reacted in time t measured in hours For the reaction, RCl
+ NaOEt +ROEt + NaCl
absolute alcohol containing 0.1097M sodium ethylate was used. Solutions containing the same concentration of the organic chlorides in alcohol were also made up. All of them were kept in a thermostat a t 35.0' C. The reaction velocity coefficients were determined by mixing 25 cc. of organic chloride solution with 25 cc. of sodium ethylate solution and titrating the unreacted alkali in a 10-cc. samDle a t regular intervals. Other measurements were made a t 50.0" C. HYDROLYSIB. Methallyl chloride (5 moles) was injected into a 10 per cent excess of 10 per cent aqueous sodium hydroxide in a horizontal autoclave 4 inches (10.2 cm.) in diameter and 30 inches (76.2 cm.) long, equipped with a stirrer rotating at 200 r. p. m. At 200" C. the products were: methallyl alcohol, isobutyl alcohol, and dimethallyl ether, 38.5 per cent; isobutyraldehyde, 17.5; isobutyric acid, 14.6; and octaglycol, 29.2. The yield of methallyl alcohol was increased in successive experiments at 180°, 160", 150°, and 120' C. At the lowest temperature the yield of unsaturated alcohol plus ether was 94.7 per cent with
20.00 22.00 24.00 27.00 59.00 61.40 64.20 67.00 1.313 1.318 1.366 1.378 1.340
44.00 76.20 1.325
apparently none of the by-products noted at the higher temperatures. The reaction was complete in 15 minutes. Methallyl chloride (5 moles) was introduced into a suspension of calcium carbonate in 2.5 liters of water in the same autoclave. Isobutyraldehyde equivalent to 70 per cent of the chloride a p plied was formed by treatment a t 140-180" C . for 60 minutes. The experiment was repeated using sodium bicarbonate instead of calcium carbonate. N o aldehyde was formed a t 114-164O C. and a contact time of 40 minutes. Methallyl chloride (5 moles) was introduced into a 10 per cent excess of 10 per cent sodium hydroxide in a 1.5-gallon (5.7-liter) autoclave a t 120" C. and reacted for 15 minutes. The yield of methallyl alcohol was 85 per cent and of dimethallyl ether, 11.1 per cent. The experiment was repeated using sodium carbonate instead of sodium hydroxide but with the same ratio of chloride to water. The yield of alcohol was 90 per cent with 4.8 per cent of ether. Methallyl chloride (2.5 moles) was reacted with a 10 per cent excess of 5 er cent sodium hydroxide under the same conditions as describe: above for 10 per cent alkali. The yield of alcohol was 87 per cent with 8.7 per cent ether. ETHERIFICATION. Methallyl chloride (2.0 moles) was stirred and refluxed with 3.0 moles of methallyl alcohol and 2.8 moles of potassium hydroxide for one hour. Approximately 84 per cent of the chloride was reacted to form dimethallyl ether in a yield of 91.0 per cent. Methallyl chloride (2.0 moles) was reacted with 3.0 moles of methallyl alcohol and 4.0 moles of 50 per cent aqueous sodium hydroxide for 2 hours under reflux. About 67 per cent of the chloride was reacted to form dimethallyl ether in a yield of 91.9 per cent. Five moles of methallyl chloride, 10 moles of ethyl alcohol, and 6 moles of 50 per cent aqueous sodium hydroxide were refluxed for 7 hours. Water was added and the ether layer was washed with water, dried over calcium chloride, and distilled. Methallyl ethyl ether was obtained in a good yield. Methallyl chloride (2.0 moles) was mixed with 3.0 moles of sec-butyl alcohol and 4.0 moles of 50 per cent aqueous sodium hydroxide and heated under reflux with stirring for 2 hours. Only
TABLE IV. REACTION OF METHALLYL CHLORIDE WITH AMMONIA Operating Conditions 1 Methallyl 2 chloride, Ammonia, moles moles 10 10
0
Methallyl Chloride Conversion to: 3 OthFr materials None None
Mole ratio reactants, 1:2:3
1:lO 1:lO
10
None
1:lO
10 10 10 20 2 2 2 9
None None None None None (NHdzCOa NHiCl NH&l
1:10 1:lO 1:lO 1:20 1:2 1:2:1 1:2:3 1:9:3
Includes 11.0% methallyl alcohol.
Solvent (total vol. 800 CC.) Water Water 50% f alcohol 50% Water 50% f alcohol 50% Alcohol Benzene None None Water Water Water Water
Time, min.
90-95 96-102
4
50-51
35
58.6
32.9
6.6
None
1.9
90-96 68-81 62-66 60-63 100 100 100 54
5 90 15 15 3 15 10
59.4 17.0 55.5 70.5 37.6 35.0 58.0 , 65.0
24.3 14.8 25.5 11.8 27.2 12.0 10.3 6.6
4.3 4.0 5.5 1.4 7.7
