940
INDUSTRIAL AND ENGINEERING CHEMISTRY
visible light) of the pigments and resins from which they are made, is shown in Table 11. The decrease in reflection factor on grinding is greater, the smaller the difference in refractive index between the pigment and the vehicle.
Conclusions The decrease in the reflection factor of certain paints on grinding is accompanied by a decrease in the proportion of aggregates. Since the paints are otherwise identical, it is concluded that a large part of the reflective power of such paints must be attributed to the presence of aggregates or clusters of pigment particles. The further fact that aggregates are much more effective when the pigment has almost the same refractive index as the vehicle suggests that air trapped within each aggregate may be the cause of their effectiveness. A necessary condition for this would be moderately poor wetting of the pigment by the vehicle so that the aggregate interstices would not be penetrated by the vehicle until aided by the grinding process. Other vehicle combinations (e. g., ethylcellulose-Vinylite, isobutyl methacrylate-butyl stearate) did not show the effect of aggregates with the same pigments; their paints retained high reflection factors after grinding, which indicates very poor wetting of the pigment. A vehicle which wet the pigment readily, on the other hand, might be expected to have low reflection factors, both before and after grinding. Inert pigments, which have an index of refraction about the same as that of most vehicles and which consequently scatter light poorly when immersed in such vehicles, would be much
Vol. 33, No. 7
more effective when in contact with air within an aggregate and could then make a paint with an improved reflection factor. Paints containing high hiding pigments, which have a refractive index already large compared with most vehicles, would increase in reflectance relatively little as the result of the presence of aggregates containing air. The presence of air is suggested as offering a reasonable explanation of the facts, but it has not been definitely demonstrated. Whatever the explanation may be, this phenomenon shows the possibility, under the proper conditions of dispersion and wetting, of making a more efficient use of inerts in white paints.
.4cknowdedgment The writ’er thanks The Lowe Brothers Company for its support of the fellowship which made this work possible and for permission to publish the results. Grateful thanks are due Walter Soller of the University of Cincinnnati, and R. W. Kewish of The Lowe Brothers Company for their assistance and advice
Literature Cited (1) Casperson, Torbjorn, Kolloid-Z., 60, 151 (1932): 65, 162 (1933). (2) Kithn, Curt, 2. ungev. Chem., 28, 126 (1915). (3) Shoulejkin, W-as.,Phil. M a g . , 48, 307 (1924).
(4) Wilcock, D. F., and Soller, W., IND.ENG.CHEM.,32, 1446 (1940).
PARTI1 of a dissertation submitted t o the faculty of t h e Institute of Scienti60 Research, University of Cincinnati, in partial fulfillment of the requirements for the degree of doctor of engineering science.
Derivatives of Allvlic Chlorides Beta-Methylglycerol and Its Derivatives G. HEARNE AND H. W. DE JONG Shell Development Company, Emeryville, Calif. excess, the reaction at room temperature is complete within a few seconds. I n fact, it can be used as an analytical method for determining the amount of the chloro alcohol in a solution. I n order to obtain the maximum yield, the P-methylepichlorohydrin should be recovered from the aqueous solution as soon as possible, for it hydrates to P-methylglycerol monochlorohydrin. This is particularly rapid a t elevated temperatures, so it is advisable either to distill under reduced pressure or to use a continuous stripping column whereby the contact time at elevated temperatures is reduced. The epichlorohydrin is obtained as an azeotrope with water. A large proportion of the dichloro-tert-butyl alcohol from the chlorohydrination of methallyl chloride is recovered as a Preparation of P-Methylepichlorohydrin dilute aqueous solution containing hydrochloric acid. This P-Methylepichlorohydrin (l-chloro-2-methyl-2,3-epoxy- can also be used for the synthesis of P-methylepichlorohydrin by supplying additional alkali to neutralize the hydrogen 0 chloride. Lime can be used instead of sodium hydroxide. /\ The following are data from a typical experiment: propane, CH2C1-C - CH2), was previously synthesized by \ Dichloro-tert-butyl alcohol (0.4mole) was added at a rate of 2 cc. per minute t o a lime slurry consisting of 120 grams of calCHa cium hydroxide in 300 cc. of water in a flask equipped with a the action of diazomethane on chloroacetone (1). stirrer and distillation column. A t a temperature of about 60” C. Dichloro-tert-butyl alcohol reacts with alkali readily to and a pressure of 135 mm., a constant-boiling mixture of the form P-methylepichlorohydrin with the elimination of one epichlorohydrin and water was distilled over as rapidly as the chloro alcohol was added to the flask. The yield was 93 per cent. molecule of hydrogen chloride (4).If the alkali is added in
HE synthesis of dichloro-tert-butyl alcohol [2-methyl1,3-dichloro-2-propanol,CH2C1C(CHs)OHCH2C1] from methallyl chloride by chlorohydrination was described in a previous article (I)of this series (I,8, IO). Its structure is similar to that of glycerol dichlorohydrin (CH,ClCHOHCHgCl); therefore we are not surprised that it has somewhat similar chemical properties. Thus it has served as the starting point for the synthesis of a number of new compounds which, by analogy with the well-known glycerol derivatives, might be termed “P-methylglycerol derivatives”. The present paper discusses the methods of preparation and some of the reactions of these compounds.
T
July, 1941
INDUSTRIAL AND ENGINEERING CHEMISTRY
The physical properties of p-methylepichlorohydrin are : boiling point 122.0" C., dai 1.1025, n9 1.4340, boiling point of azeotrope with water (25.6 per cent water) 89.8" C. One hundred grams of water dissolve 3 grams of 8-methylepichlorohydrin at 20° c. P-Methylepichlorohydrin reacts with 28 per cent aqueous ammonia and sodium hydroxide to form 1,3-diamino-2methyl-2 propanol [NH2CH2C(CHa)OHCH2NH2].This can also be prepared from dichloro-tert-butyl alcohol, ammonia, and two molecules of alkali. The product boiled a t 81.5" to 83.5' C. under 4 mm. p&ssure. It did not crystallize on standing a t room temperature.
Preparation of P-Methylglycerol Monochlorohydrin P-Methylglycerol monochlorohydrin [3-chloro-2-methyl1,2-propanediol, CHzClC(CH$OHCH20H] is formed by the hydration of P-methylepichlorohydrin (6). The reaction is best effected by stirring the epichlorohydrin with a n excess of water a t 90" to 95" C. using a small amount of a n acid catalyst such as sulfuric acid. Hydrochloric acid cannot be employed because it adds a t the oxide ring to form the dichlorohydrin. Alkalies also catalyze the hydration, but they react with the monochlorohydrin formed. The hydration is exothermic and the heat evolved will maintain the mixture at the reaction temperature, provided sufficient catalyst is present. The experimental procedure was as follows: p-Methylepichlorohydrin (500 grams) was added t o 1000 cc.
of water containing 1.3 grams of sulfuric acid and stirred at 90' to 95" C. during 2 hours. The heating and stirring was continued
for an hour, during which the mixture became homogeneous. The excess water was removed by distillation, and the monochlorohydrin was fractionated under reduced pressure. The yield was 95 per cent. p-Methyl lycerol monochlorohydrin is a colorless viscous liquid, misohe in all roportions with water, alcohol, and ether. It has the following pRyaical constants: boiling point 80" C. at 1.6 mm., da: 1.2362, n p 1.4748.
941
product from the hydration of P-methylepichlorohydrin can be used without isolating the monochlorohydrin. The procedure is as follows: An aqueous solution of p-methylglycerol monochlorohydrin prepared from 250 grama of p-methylepichlorohydrin was mixed with a slight excess of 15 per cent aqueous sodium hydroxide at 10' t o 20" C. The solution was made neutral t o phenolphthalein by the addition of a small amount of hydrochloric acid. It was extracted with ether in a continuous extractor for several hours, the ether was evaporated, and the p-methylglycerol was distilled under reduced ressure. The yield was 70 per cent based on the p-methylepichrorohydrin applied. p-Methylglycidol is a colorless liquid, completely miscible in water, alcohol, and ether. I t a physical constants are: boiling point 68" C. at 25 mm., da: 1.0420, ny 1.4299. Caution must be exercised in the handling of P-methylglycidol. Acids catalyze its hydration and polymerization and may cause these reactions to take place so rapidly and with such evolution of heat as to cause an explosion.
Dichloro- tert-butyl alcohol, the principal product from the chlorohydrination of methallyl chloride, has been employed for the synthesis of @-methylepichlorohydrin, @-methylglycerol monochlorohydrin, Pmethylglycidol, and P-methylglycerol. A similar but more complex series of compounds has been prepared from trichlorotert-butyl alcohol, a by-product from the chlorohydrination.
Preparation of @-Methylglycerol
P-Methylglycerol monochlorohydrin reacts with ammonia P-Methylglycerol [2-methyl-1,2,3-propanetriol, CH20H.and sodium hydroxide to form 3-amino-2-methy1-lJ2-proC(CH,)OH.CH2OH] can best be prepared by the hydration panediol. This boiled a t 108-112" C. under 4 mm. pressure. of P-methylglycidol. The procedure was as follows: It was a viscous liquid which, on standing for several days, crystallized to a white waxy solid melting at approximately p-Methylglycidol (1300 grams) was slowly added to 2000 cc. 3 5 O c. of water containing 0.5 gram of sulfuric acid at 35" to 40' C. When the reaction was complete, the acid was neutralized and the Preparation of p-Methylglycidol mixture fractionated under reduced pressure. The yield was about 75 per cent. The first attempt to prepare P-methylglycidol (2,3-epoxyp-Methylglycerol is a colorless, viscous liquid with the follow0 ing physical constants: boiling point 115-120' C. at 1.6 mm., da: 1.1863, ny 1.4730. /-\ 2-methyl-1-propanol, CH20H-C - CH2) was by the reaction I P-Methylglycerol can be obtained not only from P-methylI glycidol, but also directly from either dichloro-tert-butyl CHI alcohol or P-methylglycerol monochlorohydrin. The direct of metallic sodium with P-methylglycerol monochlorohydrin procedure, however, is more difficult because the glycerol according to the procedure used by Rider and Hill (9) for the must be recovered from the salt produced. This requires consynthesis of glycidol from glycerol monochlorohydrin. Alsiderable care because it is rather unstable toward acid, although some methylglycidol was isolated, the yield was poor kali, and elevated temperatures. The best method for hybecause of the formation of methallyl alcohol by a side fracdrolyzing the dichlorohydrin was by treatment a t 150" C. tion which is not fully understood. using sodium bicarbonate as a neutralizing agent. The Much better results were obtained using aqueous sodium monochlorohydrin was neutralized with sodium hydroxide hydroxide (6). The monochlorohydrin reacts a t room temat room temperature, and the P-methylglycidol which was peratures almost as rapidly as the alkali is added, but the formed as an intermediate product was allowed to hydrate glycidol, unlike the epichlorohydrin, cannot be recovered by to the glycerol in the aqueous solution. azeotropic distillation. Instead, i t is separated either by Chemically P-methylglycerol is distinguished from its extraction with a solvent such as ether or by distilling off the homolog, glycerol, by the ease with which it is converted to water under reduced pressure and separating the glycidol the unsaturated aldehyde. The reaction t o methacrolein (afrom the salt. It is necessary to remove the glycidol from the methylacrolein) occurs quantitatively by distillation of the aqueous solution as soon as possible; otherwise the yield is P-methylglycerol with dilute (12 per cent) sulfuric acid a t reduced by hydration to P-methylglycerol. Since the @atmospheric pressure (3). Under these conditions dichloromethylglycidol is synthesized in an aqueous solution, the
I N D U S T R I A L AND E N G I N E E R I N G
942
REACT WITH ISOBUTYR ISOBUTYRACETAL OF ALDEHYDE + H2SO4 ISOBUTYLENE GLYCOL
METHALLYL ETHERS
ALCOHOL + No OH
HYDROLYZE
Vol. 33, No. 7
CHEMISTRY DISTILL WITH DILUTE HZ S q
ISOBUTYLENE GLYCOL
ISOBUTYR-
METHALLYL ALOOHOL
OXIDIZE
ISOBUTYRIC ACID
I
METHALLYL BROMIDE, IOOIOE, SULFIOE, THIOCYANATE. MERCAPTAN,ETC.
'
T
, REACT ~ , "WITH R " GRIGNARO , [ ~ ~ M REAGENTS-METALS DIMETHALLYL I
CHLOROHYDRINATE
ISOBUTYLENE CHLOROHYDRIN
CHLORINATE
REACT WITH
METHALLyLCHLORIDE TRIMETHALLYLAMINE
J
DlOHLORO-lcrtBUTYL ALCOHOL
HYDRATE WITH ti2504
ISOBUTYL ALCOHOL
M E T ~ ~ ~ ~ ~ L ~OIMETHALLYLAMINE ~ ~ o R I D E
METHALLYLAMINE
AMMONIA
HYDROGENATE
HYDRATE EPICHLOROHYDRIN
DISTILL WITH ALKALI
@-METHYLGLYCEROL MONOCHLOROHYORIN
ISOBUTYLENE OXIDE
DICHLOROISOBUTYLENES
FIGURE1. DERIVATIVES OF METHALLYL CHLORIDE
tert-butyl alcohol, P-methylglycerol monochlorohydrin, 0methylglycidol, and P-methylepichlorohydrin are likewise converted t o methacrolein ( 7 ) . Glycerol is stable when heated with dilute acid a t atmospheric pressure, but by distilling with 8 per cent sulfuric acid a t 190" c. under pressure it can also be decomposed to give a fair yield of acrolein ( 3 ) .
methylepichlorohydrin but was finally accomplished by heating under reflux with 0.25 per cent sulfuric acid for 6 hours. The product boiled a t 120" C. a t 1.1 mm. pressure. An analysis showed that one of the two chlorine atoms in the molecule is easily removed with dilute sodium hydroxide a t room temperature, but the other requires more rigorous conditions.
Y\
Derivatives of Trichloro-tert-butyl Alcohol Trichloro-tert-butyl alcohol (1,3-dichloro-2-chloromethyl2-propanol, CH2C1-COH-CH2C1) is formed as a minor byCHgCl product from the chlorohydrination of methallyl chloride (a). Although the derivatives have been prepared only in small quantities, they are included here because of their similarity to those from dichloro-tert-butyl alcohol.
/"\
p(Chloromethy1)epichlorohydrin (CH2 - C-CH2C1)
was
I
CHzC1 prepared by the reaction of trichloro-tert-butyl alcohol with lime slurry a t 60" C. The product was distilled from the reaction mixture under reduced pressure, dried and refractionated. It boiled a t 89.5" C. under 31 mm. pressure. An analysis for carbon, hydrogen, and chlorine showed values in close agreement with the theory. P(Chloromethy1)glycerol monochlorohydrin (CHzCl-COH-CH20H) &H&I
was synthesized by hydrating P(chloromethy1)epichlorohydrin. This was more difficult than the hydration of p-
p(Chloromethy1)glycidol (CH20H-C-CH2)
I
was prepared
CHzCl by adding p(chloromethy1)glycerol monochlorohydrin t o an equivalent amount of sodium hydroxide a t rocm temperature. The mixture was extracted with ether in a continuous extractor for several hours. The ether was removed and the glycidol was fractionated under reduced pressure. It boiled a t 85" C. under 1.0 mm. pressure. Its analysis agreed closely with the theory. p( Chloromet hyl)glycerol (CH20H-COH-CH20H) was
I
CHlCl prepared by reacting p(chloromethy1)glycidol with four times its volume of 0.1 per cent sulfuric acid a t 100" C. for 30 minutes. The reaction takes place readily and with the evolution of heat, but is not so rapid as the hydration of P-methylglycidol. The water was removed under reduced pressure, but the chloromethylglycerol could not be fractionated since its boiling point was above 150" C. a t 0.6 mm. pressure. Its analysis showed: Carbon
Hydrogen Chlorine (total) Chlorine SaDonified with dilute K i O H a t room temp.
Found
Theory
34.8%
34.2%
6.9 26.1 26.1
25.3
6.4
25.3
. ..__
INDUSTRIAL AND ENGINEERING CHEMISTRY
July, 1941
In an attempt to prepare p(hydroxymethy1)glycidol 0
/\
(CH,0H-C-CH2),
equivalent quantities
I
of
P(ch1oro-
CHzOH methy1)glycerol and dilute aqueous sodium hydroxide were mixed and extracted with ether in a continuous extractor. However, the distribution coefficient between water and ether was so unfavorable that none of the glycidol could be extracted. The aqueous solution was evaporated under reduced pressure, leaving a mixture of salt and a high boiling residue. This was diluted with absolute alcohol and the salt was filtered off. After removal of the alcohol, a residue was left which could not be distilled even a t very low pressures. Analysis indicated that i t was principally isoerythritol, COH(CH20H),,formed by hydration of the glycidol: Carbon Hydrogen Oxygen (by difference)
Found 38.9% 7.6 53.5
Theory 39.3% 8.2 52.5
Conclusion This is the last article of a series on the derivatives of methallyl chloride. The previous publications described the
DE SCHEIDER By Jan Luyken
No. 127 in the Berolzheimer series of Alchemicaland Historical Reproductions is a fine and typical specimen of Seventeenth Century Dutch art. Jan Luyken (or Luiken) was born in Amsterdam in 1649. His art studies were carried out under Martinus Zaagmolen. Luyken first tried his hand at painting, without achieving very much, but he became eminently successful as an engraver. He died in 1712. The original engraving which we have copied is No. 90 in “Het Menselyk Bedrijf” (Human Achievement), published by Luyken in Amsterdam in 1694. The poem also by Luyken, in medieval Dutch, is somewhat obscure, but through the kind cooperation of Professor A. J. Barnouw of Columbia University, we are able to supply a proper translation:
.
THE SEPARATOR HE IS YOUR FRIEND.
WHO UNBINDS YOU,
The gross essence on the Fire Yields its spirit or its Very Best; Thus wisdom seeks through suffering, According to the nature and tendency of love, To separate towards Him the spiritual essence From the gross part in Man. D. D. BEROLZHEIMER Street New York, N. Y.
50 East 41st
The lists of reproductions and direotion? for obtaining copiea appear 88 follows. 1 to 96 January 1939, Issue, page 124; 97 to 120 January, i941, page i14. An idditional reproduotion appears eacd month.
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metathesis reactions (IO), the syntheses involving the double bond in methallyl chloride (B), and the derivatives of methallyl alcohol (8). The more important processes and products are listed in Figure 1. Some of these have been developed on a semicommercial scale under the direction of W. Engs. The number and the variety of the derivatives are proof of the reactivity and usefulness of methallyl chloride as a chemical intermediate. Many of the reactions are analogous to those of other allylic chlorides which, as a class, are particularly susceptible to chemical treatment. I n a larger sense the results illustrate the potential value of chlorination for utilizing petroleum products.
Literature Cited (1) Arndt, Amende, and Ender, Monatsh., 59,202 (1932). (2) Burgin, Hearne, and Rust, IND.ENQ. CHEM.,33, 385 (1941). (3) Groll and Hearne, U. S. Patent 2,042,224(May 26, 1936). (4) Ibid., 2,061,377(Nov. 17,1936). (5) Ibid., 2,070,990(Feb. 16,1937). (6) Ibid., 2,086,077(July 6,1937). (7)Ibid., 2,106,347(Jan. 25, 1938). (8) Hearne, Tamele, and Converse, IND.ENQ. C H E ~ I 33, . , 806 (1941). (9) Rider and Hill, J. Am. Chem. SOC.,52,1521 (1930). (10) Tamele, Ott, Marple, and Hearne, IND.ENQ.CHEM..33, 115 (1941).
