I
DAVID E. GUSHEE, Associate Editor, in collaboration with OSCAR
L. SCHERR,
Process Chemicals Co., Santa Fe Springs, Calif.
Specialty Surfactants Process Chemicals Co.’s formula for success in manufacturing specialty surfactants:
d d d
Technical competence Solving customer problems with specially tailored chemicals Equipment which allows flexible operation
P m v i o u s articles in I&EC’s series of Staff-Industry Collaborative Reports have described the manufacture of metallic soaps ( 4 ) , fatty acid amides ( 3 ) , specialty soaps ( 8 ) , synthetic detergents from petroleum in France (2), and synthetic detergents by Procter & Gamble’s continuous process (7). This article supplements those, describing the manufacture of specialty surface active agents of a variety of types and a variety of properties, as carried out by Process Chemicals Co. of Santa Fe Springs, Calif.
Reactors 5 and at reactor 2
798
4
Process Chemicals makes surfactants falling into all three basic categoriesanionic, nonionic, and cationic. In all, it produces six major types of surfactants, although the lauryl sulfates make up about one third of the company’s production. Lauryl sulfates (anionic) Fatty alkanol amide condensates (nonionic) Glycerol fatty acid esters (nonionic) 0 Polyethylene glycol fatty acid esters (nonionic) Polyethylene glycol fatty alcohol poly-
a s seen from catwalk gives access to their tops.
INDUSTRIAL AND ENGINEERING CHEMISTRY
Operator i s
ethers (nonionic) and amine polyethers (cationic) Quaternary ammonium compounds (cationic) This article gives a typical example of each of these types of surfactants, describes its uses, and points out some modifications which the company uses to make products similar but with properties changed slightly in one way or another. Process Chemical’s forte is solving specific customer problems with specific chemicals tailored to those problems -even though it may not have that exact chemical in its line. Once the chemical has been added to the line, the company then tries to find other sales outlets for it. It was formed in 1947 and made as its first product sodium sulfide, a chemical then in short supply as a result of wartime exigencies. When other companies entered this market a year or so later, Process Chemicals discontinued its production and switched to the surfactant field. The first surfactant made by the company was a polyethylene glycol stearate for use in ice cream and bread. From 1947 to 1955, the company was housed in an old wooden building in the heart of a residential area in Los Angeles. During this period the number of products continually grew. The alkanol amides, lauryl sulfates, and polyethylene glycol esters for industrial emulsifiers were added to the line. By 1955, annual sales had grown to $350,000 and monthly production to 100,000 pounds. So as to expand further, the company moved to its present location-a five-acre tract in Santa Fe Springs which the company had purchased in 1951 in anticipation of this need. Since this move, Process Chemicals has grown rapidly to where, in 1958.
Reactor 5 i s at right and a mixing tank is a t left. tors move so fast in this plant that they blur
it had gross surfactant sales of $1,500,000 and a production rate of some 500,000 pounds per month. I t has about 350 products on its list and is constantly adding more. I t is now one of the primary West Coast producers of surface active agents and has one of the most complete lines of surfactants on the West Coast. Most of its customers are also in the West. However, it has developed some products for West Coast branches of Eastern companies and ships some of these products to the Eastern plants of these companies. Market areas for other company products are also broadening, as sales effort expands. Equipment In making its specialty surfactants, Process Chemicals uses for the most part simple reactors, pumps, and tanks. There are two main processing areas: the ethylene oxide plant, where reactions using ethylene oxide and propylene oxide are handled; and the general process area, where all the other reactions are carried out. At first glance, the general process area looks like a large semiworks. The reason for this appearance is clear. When a company makes as many different products as Process Chemicals does, it makes relatively small amounts of each one. Thus, it needs many vessels, each as versatile as possible, in order to simplify scheduling of production runs. The general process area has four stainless steel reactors of varying sizes and two glass-lined Pfaudler reactors, plus five stainless steel tanks for mixing, neutralizing, heating, cooling, or holding batches of materials. The glass-lined reactors are used mostly for reactions requiring chlorosulfonic acid. Stainless steel is used elsewhere, so that choice of reactor need not be limited by materials of construction. Instrumentation is held to the absolute minimum consistent with maintaining
Note: Opera-
From the catwalk this picture shows the row of process vessels on the other side. Two Pfaudler reactors are at left center; the large reactor at right center is vessel 8, the neutralizer
product quality. All reactors have temperature and pressure indicators, while three have automatic temperature controllers. Operators control flow rates,
metering of liquids, and reaction conditions by hand. Because many of the product tend to foam, aerate, or absorb moisture when
Typical Operating Instructions How Process Chemicals Makes lauryl Sulfates PCC makes a variety of lauryl sulfates of different fluidity, foam properties, and detergency. These various lauryl sulfates have been developed over the years in response to requests for specific properties that customers have wanted in their shampoos. These properties are controlled b y the content of sodium chloride, sodium sulfate, and free fatty acid, plus the composition of the lauryl alcohol fraction used (commercial lauryl alcohols vary from 60% to 95% Clz content). In a shampoo, volume of foam depends on the Clz content. Detergency is more dependent on content of longer-chained fatty alcohols. Solid paste shampoos require high salt contents and are buffered to pH 9.0 to 9.5 with sodium bicarbonate or borax. Liquid shampoos are buffered to a lower pH (7.5 to 8.0) with sodium citrate or the like. Batch size depends on the particular lauryl alcohol used for a given product and i s adjusted to use one complete drum of chlorosulfonic acid per batch. The company does not want any ClSOsH left around in partly-full drums. The plant procedure i s about like this: ,Charge the lauryl alcohol to a glass-lined reactor. Pull slight vacuum on the reactor through an absorption system, to remove by-product HCI as it i s formed and to neutralize it. ,Charge chlorosulfonic acid from the drum, using COz pressure. Feed rate is about 4 Ib. per min. and i s controlled manually b y a needle valve; the full drum i s charged in about 3 hours. Reaction temperature is held at 75' to 90" F. b y cooling water in the reactor jacket. When the reaction is complete, pull a high vacuum on the reactor and blow the reaction mixture with COS to strip out all remaining HCI. Then pressurize the reactor with COz. During the reaction period, prepare a caustic solution in the neutralizing tank, using enough caustic and enough water to bring final pH and concentration to the desired levels. Agitate and cool to 45" F. Blow the reaction mixture from the glass-lined reactor into the caustic solution with COz pressure. Agitate to ensure homogeneity. Check batch in laboratory for sulfite content. Add sodium hypochlorite as required to oxidize sulfite to sulfate. This treatment also bleaches the product. ,Formulate to final pH and viscosify b y adding salts, excess free fatty buffering agents. e after laboratory appr
, , ,
VOL. 51, NO. 7
~
JULY 1959
799
=
T
@TO DRUMS
I
DRUMS
NITROGEN-TO
To
F
REACTOR
TO D ~ U M S
T O VENTILATING FAN,THROUGH SCRUBBER SYSTEM
-
CONDENSER
M I12 XER
-
I
I
TO DRUMS FROM DRUMS
FROM DRUMS
e- EACH REACTOR
e-
CARBON DIOXIDET O EACH REACTOR
REACTOR 2 REACTOR I
J
4
TO DRUMS
Q 1
TO DRUMS
GENERAL PROCESS AREA-NORTH SIDE
TO NEUTRALIZER
I/EC
EJECTOR
PLANT PROCESS SERIES CARBON DIOXIDE
7 1
rtiMIXER
2
5
TO DRUMS FROM DRUMS
MIXER
TO DRUMS
TO DRUMS
GENERAL PROCESS AREA-SOUTH SIDE
Flowsheet for the manufacture of specialty surfactants, Process Chemicals
800
INDUSTRIAL AND ENGINEERING CHEMISTRY
Co., Sante Fe Springs, Calif.
SPECIALTY SUR FA CTANTS pumped, they are transferred from one vessel to another with compressed nitrogen or carbon dioxide whenever possible. T o minimize permanent piping, and to keep the plant as versatile as possible, pumps are mounted on portable stands and hooked up with flexible tubing when needed. Often all six reactors are in use a t one time. So that only two operators can handle all these reactions, the reactors and auxiliary vessels are installed in two rows about 20 feet apart. Despite the heterogeneity of the operations, however, these two men can adequately handle all of these a t once. The physical operations are relatively simple even though the chemistry involved is often complex. The ethylene oxide plant, on the other hand, is more extensively instrumented and has more safety features. The whole area is separated from the general process area by a fence, and is run by one operator, closely supervised by a chemical engineer. Reactions are carried out in a 500-gallon, stainless steel pressure reactor. There are two 500gallon, pressure, scale tanks, one for ethylene oxide, and one for propylene oxide, from which these reactants are weighed into the reactor. These are backed u p by two 10,000-gallon underground storage tanks-again, one each for ethylene oxide and propylene oxide. In this area, all electrical equipment is class I, group D ; there is a manuallyoperated _sprinkler system, an automatic alarm signaling any overly-rapid pres-
Reactor 7, showing some of the auxiliary equipment, with neutralizer 8 open at right
vessel in this unit, it is always purged with dry nitrogen until a Hays gas analyzer shows it to be free of oxygen. Purging eliminates the danger that explosive mixtures might form. All equipment is thoroughly grounded and interconnected so that no static electricity can be created. Oxide in the storage tanks is kept under a constant nitrogen pressure of 50 p.s.i. and the oxide is transferred from one vessel to another by nitrogen pressure.
sure increase, and a large emergency vent line, with two pop-off valves and a rupture disk in it, running straight up through the roof from the reactor. Temperature and pressure are pneumatically controlled and are recorded on a central instrument panel. Temperature and pressure controllers are interlocked with the oxide feeding system; when one or the other exceeds a preset figure, feed values are closed automatically. Before oxide is transferred into any
Major Processing Equipment Equipment Ref.
Function Reactor
@E)
Neutralizer Mixer
Tank, storage Tank, feed, CHZCHZO Reactor, CHZCHZO Ribbon blender Grinder Drum flaker Pump, gear Pump, centrifugal Filter, plate and frame Filter, leaf Ejector, 3-stage
Flowsheet Ref. 1 2
Capacity 10 gal.
Matl. of Const. Type 316, S.S.
300
3 4
600 1,500
5 6
7
3,000 100 350
8
700
9 10 11 12 13 14 15
50 600 500 500 10,000 500 500
1000 Ib./batch
... ...
50 gal./min. 30 12 15 Size 12 310 sq. in. 10 in., to 10
mm. Hg
Temp. Control Steam jacket Gas-fired and steam coil
Working, P.S.I. 15 50
so
Atm.
Glass-lined
Steam coil and gas-flred Steam coil Jacket
Type 316,
Steam coil
Atm.
8.8.
25 75
Jacket Steam coil . I .
Type 316,
... ... ... ... ... ...
8.9.
8.8.
Type 316,
s.6.
...
... ... ... ... ... ... e..
Type 316,
...
... ... Jacket ... ... ...
Agitation Kind Blade
HP. 1
2 3
Side-entering Blade Anchor
3
10 2 5 5
Variable speed blade Blade
1
Side-entering Propeller 125 290 200
... ... ... ... ... I
.
1
1
...
. ... ... ... ... ... ... ... ... ... ...
... ...
Blade' *
.
...
...
... ... VOL. 51, NO. 7
7 '/z 15 3
JULY 1959
IVZ
...
... ... ... ... . a .
... 801
tests are run is just off the general process area to keep to a minimum the time between sampling and approval for packaging. The analytical and research laboratories are compact and well equipped. The staff includes four research men, two control chemists, and two laboratory technicians. Equipment includes a Perkin-Elmer Infracord infrared spectrophotometer, Bausch & Lomb refractometer and Spectronic 20, Brookfield viscometer, Du Nouy tensiometer, Launder-Ometer and reflectometer, microscope, centrifuge, two Beckman pH meters. and the usual laboratory glassware.
Inventory Control
General view of the ethylene oxide plant, covered with tarpaulin to keep out the cool, wet winter weather. Maze of pipes inside the corrugated metal housing is a pilot plant; instrument panel rear to the right of pilot plant i s nervecenter of the ethylene oxide plant
With the tremendous number of raw materials, intermediates, and final products which must be kept on hand, Process Chemicals has an inventory problem. Making things even worse is the advantage of buying raw materials in bulk yet the disadvantage of a relatively low production rate. The company has not yet found a truly satisfactory solution to the dilemma. I t therefore has extensive storage facilities, tankage, and inventory records, and tries to keep a balance among all these competing factors. The company has developed a system of inventory entry and withdrawal slips Ivhich requires clearance through the inventory clerk. This a t least keeps the records up to date. As for purchasing liquids in bulk, the company does so when it can get a good price, then it repackages from the tank car or truck into drums for storage at the plant. Its more common liquid reagents, such as tall oil, coconut oil, and the like, have their own permanent storage tanks.
The Manufacture
Under this assemblage of pipes, valves, and vent lines are the two underground storage tanks for ethylene oxide and propylene oxide. Each holds 10,000 gallons and i s kept under nitrogen pressure at all times. Contents are fed from here to scale tanks inside to the right when needed for a batch
CHB
Analytical Control
All raw materials are checked against specifications before they are released for use in the plant. Tests include melt-
I
HO-CH-CX-NH~
0
+ H O - C1I - C ~ ~ H ~ -~
L
indices, and infrared spectra, among others. Products are tested for such proper-
802
A
I
such as foaming tendency, ability to emulsify standard materials, or the like. The control laboratory in which these
INDUSTRIAL AND ENGINEERING CHEMISTRY
Patty Alkanol Amide Condensates. These are usually foam stabilizers, thickeners, and, when used with lauryl sulfates or other anionic surfactants, detergency improvers. A typical example produced by Process Chemicals is lauric isopropanol amide. I t is made by heating lauric acid with monoisopropanolamine (G).
PCC makes other amide condensates by a similar process. For water-soluble liquids, it uses coconut fatty acid, coconut oil, or methyl laurate as the hydrophobic constituent and diethanolamine as the hydrophilic part. By
SPECIALTY SURFACTANTS 1
1
I
I I EMERGENCY VENT TO ROOF RUPTURE DISK
-4-
I
OXIDE
PROPYLENE OXIDE
T A N K 14
TANK 14
,
REACTOR 15 WATER IN
,
p--7
PRESSURE, HIGH - L E V E L
I I
I
I-
FROM RA ILROAD NITROGEN TANK CARS PRESSURE
FROM RAILROAD TANK CARS
FATTY ACID,
*WATER
- -- - -- - - - --- - -._ TEMPERATURE HIGH-LEVEL SHUT -OFF
NITROGEN PRESSURE
OUT
FINISHED PRODUCT To
EJECTOR ETHYLENE OXIDE STORAGE TANK 13
PROPYLENE OXIDE STORAGE TANK 13
TO SUMP
a CHECK VALVE
Flowsheet for the manufacture of polyethylene glycol fatty acid and amine or alcohol polyethers
changing the hydrophobic part to oleic acid or castor oil and using again diethanolamine as the hydrophilic part, the company obtains products which are oil-soluble. Lauryl Sulfates. Largest volume market for lauryl sulfates lies in shampoos. They can be made as pastes or as clear liquids by varying the ingredients during preparation. A typical example of a simple paste is sodium lauryl sulfate. This is made by reacting lauryl alcohol
(usually not a pure compound but a mixture of straight-chain alcohols, as a pure alcohol costs too much for most uses) with chlorosulfonic acid and neutralizing the lauryl sulfuric acid with caustic soda. Hydrochloric acid gas is continuously removed by vacuum as it is formed, so that per cent of sodium chloride can be held to a minimum.
neutralizing lauryl sulfuric acid with a product of the first category above-a fatty alkanol amide condensate such as diethanolamine condensed with cocoanut fatty acid (2 moles of amine to 1 mole of fatty acid) ( 5 ) .
+ ClSOaH 25' C. NaOH HCI + CizHzsOSOaH
ClzHz60H
-+
-+
ClzHz~OS03Na
Inside the reaction building, there i s one tank each for ethylene oxide and for propylene oxide. They are mounted on scales so that operator can follow rate of weight change. VaIving i s arranged so that the underground storage tank is never connected directly to the reactor through the scale tank. Check valves prevent contents from flowing back through the system. Here, valve setting is checked on t h e ethylene oxide scale tank
+
HzO
+
NaCl
The sodium lauryl sulfates are supplied usually as 30% active pastes, with the consistency controlled by the content of sodium chloride, sodium sulfate, and free lauryl alcohol to the customers' requirements. To make a liquid rather than a paste, Process Chemicals uses some base other than caustic-for example, ammonia, diethanolamine, or triethanolamine-to neutralize the lauryl sulfuric acid.
Using these in place of the sodium enhances foaming, wetting, and detergent action in some applications, depending on what the formulator adds to them in his proprietary mixture. Process Chemicals makes modified products of this general nature by
Flaker i s used to chill and flake high melting finished products VOL. 51, NO. 7
JULY 1959
803
Such products are 10070 active liquids, are anionic-nonionic blends, and are used in compounding liquid dishwashing products, bubble baths, and shampoos. Glycerol Fatty Acid Esters. These products are used as emulsifiers by the food industry. They are mixtures of monoglycerides, diglycerides, and triglycerides, with the proportions of each controlled by the ratio of reactants and the reaction conditions. They are made by reacting glycerol with a fattv acid. CHqOH
sible to tailor-make one of these products to almost any balance of hydrophobic-hydrophilic properties desired. Polyether Condensates. These products are much like the preceding group except that they are ethers, not esters, and they are much more stable to acids, alkalies, and hydrolysis. Because of this great stability, these products are used where their inertness is needed, such as in insecticide emulsifiers and heavy duty detergents, both acid and alkaline. They are made by the same process
This compound is made in two steps. First, stearic acid is reacted with dimethylaminopropyl amine. Benzyl chloride is then added, isopropyl alcohol and then soft water are also added and finally the concentration is adjusted to 30% active. Process Chemicals also makes a series of disubstituted imidazoline quaternaries, using oleic acid or tall oil fatty acids. Quaternaries of this type are oil-soluble and have both anticorrosion and bactericidal properties.
0
0
I
il
+ HOC-C17H36-+
II H H H H C~~HSSC-OH HN-C--C--N-C~HIOH H H
245’ C.
+
230’ C.
CkzOH
N--CHg II I C,,H,,---C dH,
0
--+
+ 2 H20
\N-CZHdOH /
+HO
dH
I
CHzOH In order of increasing hydrophobicity are esters of palmitic, stearic, and oleic acids. With a given fatty acid, the higher the content of monoglyceride. the more hydrophilic is the product. Using a 1 : l mole ratio of reactants; Process Chemicals gets a product containing about 45% monoglyceride, 50% diglyceride, and 5% triglyceride. The company also can get products with higher mono contents (and correspondingly higher hydrophilicity) by using higher ratios of glycerol and higher reaction temperatures. Polyethvlene Glycol Fatty Acid Esters. This type of nonionic surface active agent is made in the ethylene oxide plant by reacting ethylene oxide with a fatty acid, and controlling the amount of ethylene oxide added so that it polymerizes to the desired chain length. Dilute sodium hydroxide is the catalyst. The products are widely used as wetting agents, emulsifiers, and cmollients. 0
II
CI7H~p~,s~,C-OH f n CHZ-CHZ (tall oil fatty acids)
‘? -
NaOH ---+
165” C.
as the ester previously described, except that alcohols or amines are used in place of the acids used in the other case. C
~
H
~
,
NaOH +~ OC\/ H~ H- C H ~ 165” C. --+
72
0
c , H ~ ~ ~ - o ( c H , - c H ? - ~ ) , - CH~--CH~OH For some uses. mixtures of ethoxy and propoxy units are superior to either alone. The propoxy chains tend to keep the products liquid and also to reduce foaming. Cationics. The outstanding characteristic of these compounds is the positive charge carried by the large organic ammonium ion. This property is responsible for the neutralizing effect the cationics have on anionic detergent residues-used in textile sofxeners and cream rinses for the hair. The positively charged organic ion is also attracted to metals, paving aggregates, and other negatively charged surfaces, leading to uses such as corrosion inhibitors and asphalt antistripping agents. In addition, some of these quaternary ammonium compounds have bactericidal activity.
0
/I
C ~ ~ H ~ ~ ~ , ~ ~ , C - O ( C H Z - CCHzCHzOH H~-~)~-I
In a homologous series of these chemicals, hydrophilic properties increase as the polyoxyethylene chain length increases and as the fatty acid chain length decreases. It is therefore pos-
Process Chemicals makes a stearyl quaternary ammonium compound which is typical of these materials.
0
r 804
4
C-J\)-CH,Cl
o
INDUSTRIAL AND ENGINEERING CHEMISTRY
l+
References (1) Fedor, W. S., Strain, B., Theoharous, L., White, D. D., IND.ENG. CHEM.51,
13 (1959).
(2) Inskeep, G. C., Mussard, A., Zbid., 47. 2 11955).
(3) k 162( (4) K 41, i w o w (5) Katzm 1952).
(6) Ibid., 2,757,143 (July 31, 1956). (7) Price, C. C., “Surface Active Agents” in “Encyclopedia of Chemical Technology,” Kirk, R. E., Othmer, D. F., eds., Vol. 13, p. 252, Interscience, New York, 1954. (8) Reese, K. M., Trusler, R. B., Bugas, I. T., IND.ENC.CHEM. 46,1354 (1954).
Processing Equipment (1E) Alsop Engineering & Mfg. Corp.,
Milldale, Conn., leaf filter. (2E) Bayview Welding Works, Wilmington, Calif., reactors, mixers. (3E) Doering, C., & Sons, Inc., Chicago, Ill., drum flaker, Model M. (4E) .Elliott Co., Jeannette, Pa., ejector, IO-inch, 3-stage to 10-mm. mercury. (5E). Fitzpatrick, W. J., Co., Chicago, Ill., grinder, ModelD. (6E) Lewis, P. B., Machine Co., Los Angeles, Calif., ribbon blender. (7E) Master Electric Co., The, Dayton, Ohio, centrifugal pump. (8E) National T a n k & Mfg. Co., Los Angeles, Calif., feed and storage tanks. (9E) Pfaudler Co., Rochester, N. Y.,reactors. (10E) Shriver, T., & Co., Inc., Harrison, N. J., plate and frame filter press, size 12, 16 plate. (11E) Viking Pump Co., Los Angeles, Calif., gear pumps.
