Acrylates and Methacrylates Ester Manufacture and Markets
Acrylate synthesis reactor. The notable thing about this reactor is its small size relative to the volume of product manufactured in it. The 55gallon drums at bottom right corner give measure of size
THE Houston plant of Rohm e~ Haas Co. produces methyl and ethyl acrylate by a unique process in which five starting materials-acetylene, carbon monoxide, an alcohol, nickel carbonyl, and hydrogen chloride-are brought together in carefully controlled ratios in a continuous reaction. This process is a modification of a reaction discovered by Walter Reppe in Germany, involving a stoichiometric process carried out under mild conditions :
+
+
+ +
4HCrCH 4ROH Ni(CO), 2HC1--+- 4CH?=CHCOOR HI NiC1,
+
(1)
Reppe's stoichiometric process is uneconomical because of low yield of acrylate and high cost of nickel carbonyl. Attempts by Reppe to make methyl and ethyl acrylate catalytically, requiring high temperatures and pressures, were equally unpromising ( 7 7 ) . Rohm & Haas research chemists came up with a solution in 1948 ( 8 ) . Although carbon monoxide gas will not react in the stoichi1 Present address, Molesworth Associates, New York, N. Y .
1 328
Last month, basic acrylate and methacrylate chemistry, and r a w material and intermediate manufacture was presented. This article describes processes used for acrylate and methacrylate esters, and markets for these esters. ometric reaction: it was found that once the stoichiometric reaction is started CO gas will react with acetylene and alcohol to produce acrylate. In other words, a catalytic reaction of carbon monoxide? acetylene, and alcohol is superimposed upon the stoichiometric reaction. The carbonyl group in the acrylate ester is derived from both nickel carbonyl (stoichiometric reaction) and from carbon monoxide (catalytic reaction). In practice, up to 80% of total carbonyl needed comes from CO gas, and the remainder from nickel carbonyl. Advantages of this continuous, semicatalytic process include high yields, relatively little nickel
INDUSTRIAL AND ENGINEERING CHEMISTRY
recovery and recycle. mild conditions, and very short reaction time. Preferred conditions include a temperature of 30 to 50' C., HC1-Ni(CO)4 equivalent ratio of 1 :1.01 to 1 : l . Z ; acetylenetotal CO ratio of 1.01 : 1 to 1.1 : 1, and an alcohol-total CO ratio of 1.1 : 1 to 3 : 1 (alcohol also acts as solvent to improve fluidity). With five raw materials to be introduced at essentially the same time in correct ratios, instruments for accurately controlling starting material feed rates are an important factor. The reaction to produce methyl and ethyl acrylate is carried out in an agitated stainless steel reactor. The reactantsnickel carbonyl, carbon monoxide, ethyl or methyl alcohol (depending on the ester being produced), hydrogen chloride, and acetylene-are introduced into the vessel under the surface. Inert gases, impurities in the feeds, traces of alcohol, nickel carbonyl, and acrylate are vented but these vented gases are scrubbed with alcohol in order to recover valuables and to remove all traces of carbonyl. The liquid stream from the reactor is stored under refrigeration to prevent polymerization and then is fed continuously to a packed axtraction column.
Recycled nickel chloride brine enters the top of the column. extracts the alcohol, salts out the acrylate, and is withdrawn from the bottom of the column. The crude acrylate comes off the top. Material from the bottom of the column goes into a series of distillation columns to separate alcohol and brine and to concentrate the alcohol. The alcohol comes off the top of the final column and is recycled to the process. The brine coming from the bottom of this final column is recycled to the wash column with the excess being returned to the nickel carbonyl unit. Inhibitors are added a t the top of the columns to prevent polymerization. The main stream containing the acrylate is washed batchwise with a soda ash solution to neutralize small amounts of HC1 and acrylic acid. The neutralized acrylate solution is fed continuously to a series of columns to produce the final product. In the first column small amounts of water, light hydrocarbons, etc., are removed overhead. In the second column the finished product is removed overhead and the heavy ends, together with some acrylate, leave a t the bottom. Inhibitors are again added to the tops of columns to prevent polymerization. Columns are operated under vacuum and acrylate monomer is condensed by means of refrigerated water. The finished monomer, after being mixed with its shipping inhibitor, is stored in large tanks. Bottoms from the second stage column are pumped to a third stage column which is also operated under vacuum. T h e overhead stream from this column contains mainly acrylate and is recycled to the first stage column while the residue, containing polymers, tars, etc., is sent to the decontamination furnace and burned. Higher acrylates, such as butyl and 2ethylhexyl acrylates, can also be produced by this semicatalytic process for large volumes. However, for relatively small volumes, it is more economical to produce these higher esters either by transesterification from methyl or ethyl acrylate (70) :
+
plant the ethylene cyanohydrin process discussed earlier : HOCH?CH?CN
H+ + ROH +
CH?=CHCOOR
(4)
As the largest ethylene oxide producer in the LT.S., Union Carbide produce ethylene cyanohydrin a t low cost from HCN and ethylene oxide. Celanese, with acrylate production at Pampa, Tex., dating from 1958, is a licensee under the Goodrich process ( 7 ) , in which ketene (from acetone or acetic acid) and formaldehyde form 0-propiolactone : CH?=C=O
-+ CH.i-C=O
Acrylate ester is produced by reacting propiolactone with an alcohol in the presence of acid : CH?-C=O AH2-(?)
'
cat.
HCzCH
C:O
+ HrO + CHr-CHCOOH
(7)
This plant is scheduled for production in Januarv 1960. Methacrylate Esters
Both Rohm & Haas and Du Pont manufacture methyl methacr) late by the same process. developed by Imperial Chemical Industries (5). Starting with acetone cyanohydrin and 98Yc sulfuric acid. methacrylamide sulfate is formed as intermediate : CH 3
ROH
-+
+ H30,
CH,-(!-CN
HSOI
CHr=CHCOOR
jointly by Dow Chemical Co. and Badische Aniline & Soda-Fabrik. for the production of acrylate esters by direct esterification of acrylic acid. The acrylic acid is to be manufactured from acetylene? carbon monoxide, and Lvater by a catalytic process developed by Reppe and used in Europe for several years (2) :
(6)
Celanese was already a producer of the basic raw materials a t Pampa. Recently plans were announced by DOWBadische. a new company formed
I OH
--f
CH, CH?=&-CONH2.
H,SO,
(8)
This is not isolated, but reacts \kith metha-
H4
CHi=CHCOC)CH, ROH + CH,=CHCOOR CH,OH
+
(2)
or by direct esterification of acrylic acid:
+
H f
CH>=CHCOC)H ROH + CHF=CHCOOR H?O ( 3 )
+
Other Acrylate Processes
Rohm & Haas is the largest producer of acrylate monomers in the U. S. Both present competitors and a third one close to production use different processes. Union Carbide Chemicals, who began production of acrylate esters in 1949, use a t their Institute, W. Va.,
Decontamination furnace of the acrylate plant. All vapors that might contain nickel carbonyl are passed through this decontamination unit before venting through the 150-fooI stack. The man at the bottom gives some idea of its size VOL. 51, NO. 11
NOVEMBER 1959
1329
I/EC
PLANT PROCESS SERW
WASH CRUDE TO RERUN AREA NICKEL CARBONYL FEED
ALCOHOL FEED
EXCESS BRINE ACETYLENE FEED
TO ALCOHOL DEHYDRATION
1
-L$J
OLING
ji STEAM
w k
SYNTHESIS
SEPARATION
6 H E D CRUDE FROM WASH COLUMN
,
SODA ASH SOLUTION
SODA ASH MEASURING
c
U
1 1
CONDENSER INHIE ITOR
CONDENSER
INHIBITOR
I z CRUDE FEED W
-)n
c
*STEAM
3 I\
1 t-
RESIDUE
PURIFICATION
Flowsheet for the manufacture of acrylate monomers, Rohm & Haas Co., Houston, Tex.
1 330
INDUSTRIAL AND ENGINEERING CHEMISTRY
w
ACRYLATES A N D METHACRYLATES no1 to produce methyl methacrylate: CH3
I
CH ?=C-CONHz CHB
.HrSOa
CHZ=&-COOCH~
+ CHaOH
+ NHiHSOi
(9)
Both steps are carried out continuously. At Houston, Rohm & Haas has two identical units for manufacture of methyl methacrylate. Acetone cyanohydrin and concentrated sulfuric acid are pumped into a cooled hydrolysis kettle to make the intermediate methacrylamide sulfate. The stream leaving the hydrolysis kettle is dehydrated a t steam temperature. After cooling, it goes into an esterification kettle where it is reacted with methanol continuously. T o prevent polymerization, inhibitors are added a t various points in the process. The esterified stream is pumped to the acid stripping column. Methyl methacrylate, methanol, and some water come overhead while the residue, made up of sulfuric acid, ammonium bisulfate, and water, is sent to the ammonium sulfate plant. The overhead stream from the acid stripping column enters a rectifier column where methyl methacrylate with some methanol comes over the top, is condensed, and sent to the wash column. T h e bottoms from the rectifier, containing methanol and water, are sent to a methanol recovery column. Recovered methanol is recycled to the esterification kettle. The water solution leaving the bottom of the column, containing some methyl methacrylate and methanol, is recycled to the rectifier column for recovery. Crude methyl methacrylate (free from methanol) comes off the top of the wash column. This crude material is shipped to the Knoxville, Tenn., p!ant for further purification by distillation. T h e inhibitor introduced in processing is sufficient for shipment of crude methyl methacrylate. The higher methacrylates are made at Houston (and a t the Rohm & Haas’ Bristol plant) by the process originally used by Rohm & Haas for methyl methacrylate, involving the dehydration with phosphorus pentoxide of the a-hydroxyisobutyrate ester obtained from acetone cyanohydrin and a fatty alcohol. Because several higher methacrylates are made in the same equipment, batch operation is necessary.
both used to make a series of tert-alkylamines-tert-butylamine, tert-octylamine, tert-nonylamine, Primene 81-R (12-14 carbons), Primene JM-T (18-22 carbons), and menthane diamine. The process starts with reaction of H C N with an olefin such as isobutylene:
+
+ +
(CH3)2C=CHz HCN H Y S O+ ~ (CH,),C-NH?.H?SOa HCOOH (10) The resulting tert-butylamine sulfate is neutralized with ammonia to give tertbutylamine:
+ +
plant with 500,000-pounds-per-year capacity to investigate a different route involving oxidation of isobutylene with oxides of nitrogen to give a-hydroxyisobutyric acid :
CH3-
IH3 =CHr
CH3 CH3-C!-COOH
I OH
(12)
The hydroxyisobutyric acid is then dehydrated to methacrylic acid : CHI
CH3
+ CHr=L-cOOH
( C H ~ ) ~ C - N H ? . H Z S O ~NH3 -+ ( C H ~ ) ~ C - N H Z NH4HSO.i ( 1 1 )
CH,--d-cOOH
Ammonium bisulfate by-product from this operation, as well as from HCN, methyl methacrylate, and higher methacrylate units, is combined with additional ammonia in the 300-ton-per-day ammonium sulfate plant. Ammonium sulfate is sold to fertilizer manufacturers in the Southwest and is also exported.
Methacrylate esters would be produced by direct esterification of methacrylic acid with the appropriate alcohol.
Other Methacrylate Processes
The acetone cyanohydrin process is the only methacrylate process used commercially in this country. However, Escambia Chemical Co. recently disclosed plans ( d ) to construct a pilot
I
OH
(13)
Markets
A wide range of acrylate and methacrylate esters are available commercially from methyl to 2-ethylhexyl in the acrylate series and methyl to stearyl in the methacrylates. There is a n equally wide variation in the properties of the polymers prepared from these monomers. Lb‘hereas poly(methy1 acrylate) is a tough, rubbery polymer which forms a pliable film of high extensibility, poly-
fert-Alkylamine and By-product Manufacture
Completing extensive plant integration a t Houston. several nonacrylic units are tied in with other manufacturing operations, providing an important key to over-all product economy. Ammonia and hydrogen cyanide are
The methyl methacrylate plant. facilitate maintenance
Note the open structure a t top for cranes t o
VOL. 51, NO. 1 1
NOVEMBER 1959
1331
(methyl methacrylate) is a relatively hard material which, in cast sheet or molded form, can be sawed, carved, or worked on a lathe with ease. In both the acrylate and methacrylate series, progressing from methyl to ethyl to nbutyl ester, the polymers become softer, more extensible, and tackier, with the acrylate in each case having these properties to a greater degree than the corre-
sponding methacrylate. A minimum in the brittle point is reached in the acrylate series with n-octyl ester and in the methacrylate series with n-dodecyl methacrylate. The long-chain acrylates and methacrylates, such as n-octadecyl esters, giye polymers which, as a result of side-chain crystallization, are waxlike solids becoming soft and tacky above their relatively low melting points. As would be
expected, solubility of the polymers in organic solvents increases and water absorption decreases as the alcohol portion of the acrylate or methacrylate ester is lengthened. All of these acrylates and methacrylates give polymers exhibiting outstanding transparency and aging properties which have made them of interest in a wide variety of applications. In addi-
RECYCLE METHANOL STEAM
KETTLE C 0 ND ENSAT E
m
CONTINUOUS HYDROLYSIS
I
ESTERIFICATION
+CONTINUOUS
-
' I
I
y
RECYCLE METHANOL
INHIBITOR
I
k
i
CRUDE METHYL METHACRYLATE TO RERUN UNIT
WATEF
SIMILAR TO ETHYL ACRYLATE RERUN
f
l
SURGE
STEAM
STEAM
_ I
I
t
ACID RESIDUE TO *AMMONIUM SULFATE PLANT
n
SEPARATION
w
Flowsheet for the manufacture of methacrylate monomer, Rohrn & Haas Co., Houston, Tex.
1 332
INDUSTRIAL AND ENGINEERING CHEMISTRY
w
ACRYLATES A N D METHACRYLATES tion, a broad range of physical properties may be obtained by copolymerizing acrylates and methacrylates with each other. Thus, considerable variation in properties such as hardness and minimum film-forming temperature can be obtained by copolymerizing methyl methacrylate and ethyl acrylate in varying proportions. Acrylates and methacrylates are also widely used in copolymers with other monomers such as acrylonitrile, styrene, vinyl acetate, vinyl chloride, and vinylidene chloride. Major applications for acrylate and methacrylate polymers and copolymers are discussed below: Cast Sheet. This product developed from one of the first applications in the plastics field for which acrylics were investigated-as an interlayer for safety glass. In manufacturing laminated glass with acrylic esters, one step was cast polymerization of the monomers berween plates of glass. When methyl methacrylate was polymerized by itself in this way: the polymer was found to separate from the glass to give a rigid transparent sheet. After extensive experimental work, the first poly(methy1 methacrylate) sheet material was introduced commercially in 1936. This sheet was crystal-clear! weather resistant, and tough. Soon the Army Air Force discovered that on the score of light weight. ease of forming, and high impact strength: this sheet met requirements for a glazing material for military aircraft, \Yorld War I1 enormously expanded the need for material for this application. The rapid rise in air transport after the war stimulated demand for material for commercial aircraft. O n the military side, pressurized, large-canopy, high-speed aircraft flying at extreme altitudes created a need for acrylic sheet with higher resistance to crazing. I n 1951, a modified cast acrylic sheet was introduced which had much improved craze resistance, and this sheet soon came into general use on both military and civilian planes. While these developments were in progress, procedures were worked out for biaxial stretching, which mparts to acrylic sheet much greater resistance to impact and cracking. Development of the stretching technique was made possible by collaboration of several leading plastics fabricators, U. S. Air Force, and Rohm &: Haas plastics laboratories. The improved properties of stretched sheet have already led to its widespread use in glazing of high performance military aircraft, and in both turboprop and jet civilian transport planes. While use of acrylic sheet in aircraft glazing continues to grow, it recently yielded first place among volume applications to the manufacture of signs, Large, interior-lighted, outdoor signs comprise the largest portion of this mar-
ket. with indoor, edge-lighted signs also a n important factor. New fabricating techniques, development of corrugated and patterned designs, and a complete spectrum of colors have greatly broadened cast sheet markets, which now include lighting diffusers and covers; window glazing in schools. industrial plants, and wherever else breakage is a threat; skylights, military plotting boards, chalkboards for schools, boat windshields, instrument panel covers, and industrial applications such as office partitions, machine guards. seethrough models, and many others. Molding Powders. I n response to the demand from the plastics industry for an acrylic resin molding powder to match the permanence. clarity, and strength of acrylic sheet. molding powders for both compression and injection molding were introduced in 1938. based on methyl methacrylate. From the start principal application of these powders has been on automobiles. including lenses for steering wheel medallions. instrument panels, radiator ornaments and escutcheons, and lenses for stop lights, tail lights, back-up lights, and braking lights. After World War I1 many improvements were made in acrylic molding powders. These improvements stimulated their use in nameplates for home appliances, in dentures. optical parts. personal accessories, extruded sheet for fluorescent lighting diffusers and for the molding of letters for outdoor signs. I n 1955 a tough, high impact acrylic molding material was introduced, and its use is steadily increasing for a number of applications, including heels for women’s shoes,keys on business machines, housings for electronic equipment, vending machine parts, and control knobs for radio receiving sets. I n 1958, a styrenemethyl methacrylate copolymer molding powder was made available for use in those applications not requiring the excellent weathering and color retention of the higher-priced straight acrylics. Emulsion Polymers. This categorv is the most diversified of all of the acrylic materials. Historically, markets were opened in major industries in this order: leather, textile, paper, and paint. O n a volume basis, however, today’s marketing picture inverts this order and puts paint first. Consumption by the paint industry has soared in recent years. It ha5 been estimated that annual production of acrylic latex paints in 1960 will be in excess of 10,000,000 gallons (9). compared with 1,000,000 gallons in 1954. Production of new acrylic paints for exterior application on wood is expected to expand this market substantially. The coming years should see a sharp increase in production of paint made with 100% acrylic base (primarily copolymers of methacrylates and acrylates) and
of paints based on copolymers of acrylate esters with vinyl acetate or with styrene. Of special interest is the recent development of thermosetting acrylic emulsions which are certain to find numerous applications in industrial coatings. In the paper industry, acrylic polymer dispersions are used as binders for pigmented coatings; as clear, grease-resistant coatings; as saturants; and as ingredients in heat-sealing adhesives. I n pigmented coatings, resins can be manufactured with excellent pick resistance, wet rub resistance, color, gloss, and printing quality. Principal advantages in clear coatings are resistance to oils and solvents, freedom from color, and permanent flexibility. These properties also are desirable in many grades of saturated paper. I n heat-sealing adhesives, acrylic polymers permit considerable freedom in formulating to specific requirements as to flexibility and heat-sealing temperatures; the desired properties, once achieved, do not vary with age. I n the textile field, acrylic emulsion polymers are used in place of rubber latex as binders for the relatively new nonwoven fabrics, as backings for automotive and furniture upholstery fabrics, and as bonding agents in pigment dyeing and printing. I n these applications, excellent binding efficiency, superior stability to light and aging, and ease of handling give the acrylics important advantages over natural and synthetic rubber latices. Many different acrylic emulsion polymers and copolymers are used to impart varying degrees of hand and drapability to a wide variety of fabrics from natural and synthetic fibers. The earliest use for acrylic polymer dispersions was in finishing of leather, as base coats for nitrocellulose finishes. and as components of water finish systems. -4s base coats for nitrocellulose finishes, acrylic polymers produce permanently flexible and strongly adhering coatings which not only do not require any plasticizer. but are effective in preventing migration into leather of plasticizers present in subsequent lacquer coats. A large proportion of shoe upper, upholstery, and garment leather has been finished for many years with acrylic polymer dispersions. There is increasing use of these dispersions as components of waterbased finishes, where the acrylic polymer improves washability, adhesion, flexibility, and leveling of the finish. Synthetic floor polishes based on acrylic emulsions are rapidly gaining acceptance in a market previously dominated by natural waxes ( 3 ) . Acrylic emulsions have also found application as sealers in the building products industry, preserving attractive colors in cement products by sealing in white salts, and as vehicles for wire enamels applied from aqueous dispersion (72). VOL. 51, NO. 1 1
0
NOVEMBER 1959
1333
This I s Rohm & Haas’ Monomer Plant Product Breakdown Today
Houston (Deer Park), Tex. Methyl acrylate Ethyl acrylate Butyl acrylate M e t h y l methacrylate (crude only) Higher methacrylates Knoxville, Tenn.
for metal decorating. These coatings are featured by very rapid curing, whether air-dried or baked, excellent flow and leveling, color retention, durability, alkali and salt spray resistance, and sufficient toughness to withstand fabrication. Water-Soluble Polymers. Methyl acrylate is converted to sodium polyacrylate by first polymerizing the monomer in aqueous emulsion and then saponifying the poly(methy1 acrylate) :
2-Ethylhexyl acrylate Methyl methacrylate Higher methacrylates
Solution Polymers. These include polymers prepared in mineral oils for use as lu,bricating oil additives, and those prepare8 in organic solvents for use in formulating protective coatings. I n the oil additive field, polymerized higher acrylate and methacrylate esters are used as viscosity index improvers and pour point depressors for crankcase oils. More recent variations show the added property of dispersing cold sludge in such oils. Coating vehicles for application from solvent systems have been produced from methacrylate esters to a greater extent than from acrylates, because of the hardness, greater resistance to alkalies and other chemicals, and better electrical properties of the methacrylate polymers. However, the acrylates are used in these vehicles as internal plasticizers. The methacrylate polymers and copolymers are readily prepared in a wide variety of polar solvents, of which aromatic hydrocarbons, esters, and ketones are most commonly used. These solutions are used as vehicles for heat-resistant white enamels of good color retention; fumeand chemical-resistant appliance enamels; luminescent coatings; flexographic printing inks, and printing vehicles used on vinyl plastics. Recent developments include the introduction of thermosetting acrylic coatings, exhibiting greatly improved adhesion and permanence, and automotive lacquers based on methyl methacrylate, now used on all General Motors models, with outstanding features being improved color retention, durability, and high gloss. Methyl methacrylate is also being copolymerized with drying oils for manufacture of methacrylated alkyd resins, which are particularly useful in coatings
1 334
Acknowledgment
cat.
CH2=CHCOOCHs [-CHz-YH-
]
NaOH
__f
COOCH8
Methyl methacrylate (distilled) Bristol, Pa.
versatile surfactants exhibit excellent foaming properties and are used in hair shampoos and industrial cleaners, with many other applications under investigation (7). The acrylate and methacrylate esters are a versatile group of monomers. Their future looks even stronger than their short past.
[-cHz-yH-
COONa
]
(14)
Sodium polyacrylate produced from methyl acrylate has better clarity and color than the product made from acrylonitrile, and is widely used as a thickening agent for synthetic rubber latex. With Unsaturated Polyesters. In recent years, there has been increasing use of methyl methacrylate in a 50 to 50 ratio with s:yrene in unsaturated polyesters for corrugated sheet and other applications where the significantly improved weatherability, transparency, and color retention of the methacrylate system is important (74). A related development is the introduction of acrylic sirup, a solution of acrylic polymer in monomer, primarily based on methyl methacrylate, and containing a small amount of a cross-linking agent. This product is recommended for reinforcement with glass or synthetic fibers by techniques employed with unsaturated polyesters, Acrylic sirup is water-white, has good adhesion to glass fibers, and the excellent weatherability usually associated with acrylics (73). Specialty Elastomers. Copolymers of ethyl acrylate with 5% chloroethyl vinyl ether and copolymers of butyl acrylate with 5 to 15% acrylonitrile are used as elastomers. After vulcanization, these polymers have a combination of heat resistance and oil resistance useful in specialty applications such as gaskets for automatic transmissions in automo ive engines. Intermediate. Methyl acrylate is used as an intermediate in manufactur: of amphoteric surfactants ( 6 ) . A fatty amine is added to the double bond of the acrylate and the resulting alkylaminopropionate is saponified with alkali:
The authors thank Vincent C. Henrich and Donald W. Kenny for their guidance through Rohm & Haas’ Houston complex, and J. H. Geniesse and Colin C. Campbell for assistance in preparing the manuscript.
Major Price Reductions Were Made in Less Than a Decade Date of Change
New Price, $
Methyl Methacrylate 12/1/48 1/1/51 12/13/55 3/1/56
0.445 0.35 0.32 0.29
Methyl Acrylate 12/23/48 6/15/49 11/15/49 2/2/53 10/1/55
0.55 0.50 0.49 0.42 0.37
Ethyl Acrylate 4/1/48 5/23/49 6/15/49 2/2/53 2/9/55 10/1/55
0.56 0.49 0.48 0.42 0.3875 0.34
Literature Cited
(1) Chem. Eng. Neeres 37, No. 5 , 46 (Feb. 2, 1959). (2) Ibid., No. 29, 25 (July 20, 1959). (3) Chem. Week 84, No. 24, 117-121 (June 13, 1959). (4) Zbid., No. 25, 91 (June 20, 1959). (5) Crawford, J. W. C. (to Imperial Chem. Ind, Ltd.). U. S. Patent 2,101,821 . . (Dec. 7, 1937). ( 6 ) Isbell, A. F. (to General Mills, Inc.), Zbid., 2,468,012 (April 19, 1949). (7) Kung, F. E. (to B. F. Goodrich Co.), Ibid.,2,352,641 (July4, 1944) ; 2,356,459 (Aug. 22, 1944). (8) Neher, H. T., Specht, E. H., Neuman, A. (to Rohm & Haas Co.), Itid., 2,582,911’(Jan. 15, 1952). (9) Rauscher, F. J., Reid, W. H., Chem. Eng. ,Yews 36, No. 47, 64-8 (Nov. 24, 1958). CiSH37NH2 CH?=CHCOOCHa --f (10) Rehberg, C. E., Org. Syntheses 26, 18 (1946). C18H37NHCH2CHzCOOCHn (15 ) (11) Riddle, E. H., “Monomeric Acrylic Esters,” p. 4, Reinhold, New York, 1954. C18H31NHCHzCH2COOCH3 (12) Rosenberg, J., Greenberg, H. L., NaOH + Cl~H3iiYHCH2CH?COONa Modern Plastzcs 35, No. 4, 173 (December 1957). CH30H (16) (13) Ross, J. A., Mead, B., Rundquist, J. T., Zbid., 35, No. 12, 109 (August Addition of a second molecule of methyl 1958). acrylate gives an alkylaminodipropionate, (14) Smith, A. L., Lowry, J. R., Zbid., 35, No. 7, 134 (March 1958). ClsH37N(CH2CH2COONa) 2. These
INDUSTRIAL AND ENGINEERING CHEMISTRY
+
+
+
