A S t a f f = h d u s t r yCollaborative Report
T
HE American housewife who is being rapidly educated to the use of something other than soap in her dishpan and washing machine is probably inclined to think that some wonderful chemist has been sitting up nights thinking of a way to lighten her daily routine. Anyone listening to the daytime radio will certainly understand how she has been led to that conchsion. However, milady is misinformed. The consumer packaged powders and liquids which now account for the great majority of the “synthetic” detergents produced are actually the incidental result of an attempt to meet the long-standing requirement of the textile industry for a surface-active agent which would be effective under the conditions of acidity and hard water encountered in textile processing. The f i s t feeble attempt to meet this need was sulfated cmtor oil or turkey red oil named for the turkey red dye bath in which it is used. Turkey red oil was the only contender in the field for almost a hundred years but in the 1920’s German manufacturers of synthetic organics began a concentrated search for a substitute for map or a “universal soap.” The first result of this search was the development of Nekal, an alkyl naphthalene sulfonate. This type compound found application as a wetting agent, but it had almost no detergent value. The quest took a big step forward when Bertsch (I) localized the cause of most of the shortcomings of conventional soap in the active carboxyl group. From this
e
.
e
point of common departure H. T. Bohme, A,-G., and I. G. Farbenindustrie took the lead in attempting to block the troublesome group (3,IO). Bohme produced the first group of commercial products-the Avirol series, sulfuric acid esters of butyl ricinoleic esters, in 1928 (8). Two years later they introduced a series of fatty alcohol sulfates under the trade name of Gardino). (8, 8, 16). These compounds were made by sulfating fatty alcohols obtained by the high pressure hydrogenation of fatty acids (12). During the same period, I. 0. Farbenindustrie, taking a different approach to the problem, concentrated their investigations on esters of fatty acids. In 1930 they marketed in Germany the Igepon A series which comprised fatty acid esters of hydroxyethanesulfonic acid (4,8, IS). The “A” in the name derives from dithan, the German spelling of ethane. The A-type Igepon is an ester; it proved to be too unstable for many applications, and in 1931 1. G. Farbenindustrie submitted the Igepon T series to the German market (8, 13). These products represent still another approach to the elimination of the carboxyl group. They are amides-derivatives of taurine which gives the group iL9 type name-and are sufficiently stable for most textile processing work except the carbonizing of wool where a strong sulfuric acid bath is encountered. Surprisingly enough, these pioneer surfactank are still on the 1626
September 1950
INDUSTRIAL AND ENGINEERING CHEMISTRY
market in essentially their original form. Avirol is still made by Bbhme in Europe. Gardinol in the United States has become Duponol on the D u Pont label and Orvus and Dreft when made by Procter and Gamble. Igepon A types are still made by General Aniline & Film, although it was orginally thwght that they would be replaced entirely by the compounds of the T series. Igepon T has enjoyed a steady expansion of market up to the present time in spite of the advent of the alkyl benaene sulfonates (Santomerse, Ultrawet, and Oronite) resulting from American extension of the German work on the alkyl naphthalene sulfonates, which produced the first cyclic-derived detergent, Nacconol, introduced in 1933 by National Aniline and Chemical Company. The migration of the synthetic detergents to the United States is in itself an interesting story (6). The first immigrant to arrive was Gardinol, presented under the sponsorship of National Aniline in 1930, the same year that it was introduced in Europe (7,8,16). National Aniline offered the German product under a marketing agreement with Bohme. However, in 1932 Du Pont and Procter and Gamble became interested in the fatty alcohol sulfates and subsequently manufactured and sold them in this country, while National Aniline concentrated its efforts on the development of its own Nacconol producta. I n the textile field, the fatty alcohol sulfates were marketed under the trade name Gardinol by the Gardinol Corporation (controlled by Du Pont and Procter and Gamble) until 1946 when it wm dissolved and went out of business. Both Du Pont and Procter and Gamble are still making and selling the fatty alcohol sulfates under their reapective trade names under license from American Hyalsol Corporation, the capital stock of which waa vested in the Alien Property Custodian. Other manufacturers have also taken licenses from American Hyalsol Company.
1627
The Igepon-type surfactants immigrated in a simpler fashion. When the series was first developed, I. G. Farbenindustrie transmitted the production details to their American subsidiary, General Aniline Works, Incorporated, and suggested that they consider producing the materials in this country if they thought the potential market warranted it. Production of Igepon A waa begun at the General Aniline plant a t Linden, N. J., in 1931, and the following year Igepon T was produced a t the same site. All the Igepon products made in this country since that time have been made at this same plant with the exception of a small wartime production a t the company’s Rensselaer, N. Y., plant. Aside from the basic technology, the American production technique for these compounds has been developed independently of the German practice. I. G. Farbenindustrie had made less than 80,000 pounds of Igepon T in Germany when the fist production came out of the Linden plant. In fact T gel, the largest selling Igepon in this country, has never been made in Germany. It was developed entirely a t Linden and waa f i s t produced there in 1933. Its popularity reflects the textile industry’s preference for an easy-to-handle dustless product. In 1940 I. G. Farbenindustrie sold the American rights to the patents covering the manufacture of Igepon (6) and several other compounds to General Aniline. Shortly after the acquisition of the patents by General Aniline the United States declared war on Germany and the foreignowned stock of the company waa confiscated by the Alien P r o p erty Custodian (14). Since the end of the war the federal govcrnment has disposed of most of the equities acquired under this act. However, General Aniline remains under government management because of a court action brought by a Swiss corporation which claims to be the majority stockholder. They claim that because their incorporation is in a country which was never
Weish Tanks for Oleic Acid and Phosphorus Trichloride Used in Production of Oleic Acid Chloride Air filtering and drying system oylinders are uhown in background
1628
I N D U S T R I A L A N D ' E N G I N E E R I N G CHEMISTRY
Vol. 42, No. 9
Figure 1. Flow Sheet for Production of Igepon T at Linden, N. J., Plant of General Aniline & Film Corporation
INDUSTRIAL AND ENGINEERING CHEMISTRY
Septenhr 1950
TABLE I. KEY to Figure 1
Capacity, Gallons Material 185 Carbon steel
PROCESS VESSELB
Vessel Walls Lining i/rinch homogeneous lesdlined
2 3
Name PCli weigh tank (6000-lb. scale) Oleic acid weigh-tank Acid chloride kettle
4
Acid chloride aone tank
58
8
Acid chloride weigh tank (8oOo-lb: scale) Acid chlonde weigh tank (sooO-lb. scale) Methyltaudne weigh tank (6000-lb. pcale) Methyltaume weigh tank (6000-lb: soale) NaOH weigh tank (4OOOlb. scale)NaOH weigh tank (4000lb. pale) Auxillary kettle
3000
Stainless steel
9
Condensation kettle
3000
Carbon steel
Brick
Spray dryer feed tank
6800
Carbon steel
Loose lead-lined
1
5b
68 0b 7s 7b
10
600 750
Carbon steel Carbon steel
1500
Carbon steel
.............
Temperature Control
Kind
..........
.............
............
.............
.............
250
Carbon steel
501
Carbon steel
766
Carbon steel
768
Carbon steel
.............
200
Carbon steel
.............
250
Carbon steel
............. .............
.............
LINDEN, N. J., PLANT
General Aniline’s Linden plant is known officially as the Grasselli Plant because it was originally part of the Grasselli Chemical Company installation for the production of aniline dyestuffs and heavy chemicals. I n 1924 I. G. Farbenindustrie, seeing the growth of the American chemical industry behind increasing protective tariffs and wishing to get back into the American market from the inside, formed a joint company with Grasselli Chemical Company. The new company, Grasselli Dyestuff Corporation, acquired the entire dyeatuff business and manufacturing facilities of the Grasselli Chemical Company. Consequently the Grasselli Chemical Company’s Linden plant was literally split down the middle. The heavy Chemicals half of the installation was retained by Grssselli Chemical Company and the dye works became the property of the new Grasselli Dyestuff Corporation. When, in 1928, D u Pont bought out the Grasselli Chemical Company, it did not w u m e that company’s interest in the dyestuff company, I. G. Farbenindustrie waa the logical purchaser of this interest and assumed full ownership of Grasselli Dyestuffs. Shortly after this acquisition I. G. Farbenindustrie changed the name of the company to General Aniline Works, Incorporatel. I n 1939,shortly before the transfer of ownership of the company from the German I. G. to Swiss I. G., the name was changed again to its present form-General Aniline & Film Corporation. CHEMISTRY OF IGEPON T
The American patent which covers the manufacture of Igepon is particularly interesting in that i t potentially applies to an almost unbelievable number of compounds (6). In essence it specifies a compound of the type: R2
( - -- - N1
Agitation
S/r-inch homogeneous lead- Steam and cooling water Lead covered horseshoe lined jacketed ‘/r-.inch homogeneous lead- l/n-inch lead steam coils Lead covered blade lined around outside of lower C one I/a-inch homogeneous lead............. lined ............. ............. I/r-inch homogeneous leadlined
at war with the United States their property has been confiscated illegally. The federal government contends that the Swiss company is only a dummy for the German 1. G. Farbenindustrie. Until these claims have either been confirmed or denied the United Statee cannot obtain a clear title to the company and 80 cannot dispose of it. General Aniline preserves the conventional organizational form of a private industry with the United States government as almost its only stockholder.
RI - - - _ -
1629
_ _ _ _ _ R,
RI, R2, and R, are branched or straight aliphatic, cycloaliphatic, or aromatic hydrocarbon groups, and may even include
............. .............
............. .............
.............
............. .............
.............
Steam and aooling water Stainless steel anchor jacketed 1.5-inch stainlesa steel Stainleeu steel four-finsubmerged coils steam gered gate or cooling water Five turns, 2-inch lead sub- Wooden gate merged coil for steam
Power, hp-
.. .. 10
1.5 3 a .
.. ..
.. .. ..
25 12.5 25 6
heterocyclic rings. It is further assumed that at least one solubilizing sulfonic or sulfuric acid ester group is attached to one of the R’s. One or two of the R’s may be hydrogen provided the total carbons in all three R’s are not less than eight. If the R’s are limited to a maximum of twenty carbons it is certainly not difficult to imagine thirty different hydrocarbon configurations at any of these positions. This would permit 30 X 30 X 30 27,000 various structures based on carbon arrangements alone. Since a sulfonic or a sulfuric acid ester group will be substituted on one or more of the R’s and these groups may exist as free acids, metallic salts, or organic-base salts, we may assume ten variables for the various metal salts and the free acids, and a t least six for the substitution and have 27,000 x 6 X 10 = 1,620,000variations. The General Aniline & Film Corporation has prepared about 200 of these compounds which certainly leaves a vast number of potentially valuable surfactants among the still unexplored Igepon-type compounds. If we restrict our considerations to the commonly accepted essence of the patent-namely, acyl alkyl taurates-represented by the structural scheme,
-
R2
RI--CO&
CH2 CH$30a-Ra
there are fewer possibilities. R1 then represents hydrocarbon radicals of the fatty acid series. For economic reasons, it is probable that the number of carbons in RI will be between twelve and eighteen. Rz represents an alkyl or cycloaliphatic group which should range from one to eight carbons. Total carbons in R1 and Rp preferably should be not less than twelve nor more than twenty-one. Beyond these limits the quality of the product falls off sharply in one of several properties. Ra may be a metal or an organic base or hydrogen. A computation of the number of possible products under the above-stated limits might reach 1OOO. The effect of changes in structure are fairly well deiined. Little detergency is obtained unless R1 and RS combined contain at leaat twelve carbon atoms. Detergency is increased by increasing the length of either R, or R, or both. The limit is reached at approximately sixteen carbon atoms for R1 if the chain is straight and saturated. If unsaturated, then maximum detergency occurs a t approximately eighteen carbons, and i t is believed that with more unsaturation the masimum length of carbons i s further increased. Departures from straight chain in R1, by branching or by introduction of a solubilizing group, will decrease detergency but increase the wetting power. A
1630
INDUSTRIAL AND ENGINEERING CHEMISTRY
decrease in the Icngth of €3, increases both solubility and wetting pvwer. If R1is kept within twelve to sixteen carbon atoms and if the size of the Rngroup is increased from a methyl to a higher homolog such as the butyl or amyl group, the resulting Igcpori becomes more soluble in spite of the molecular weight incrcmr. If R, is twelve carbons, the solubility of the Igepon passe.; t.hrough a maximum when Rt is a four-carbon straight chain. Wetting increases with increase in the length of Rg until R,and R, combined contain approximately eighteen carbons. Further increase in 112 brings on a decrease in wetting. Rt map be hydrogen, but when a taurine is used a substitution of a t lcnst one carbon group enhances the properties of the resulting product tremendously. FVhen amines other than taurine are employed, desirable products might be produced with only hydrogen a t this point. Lauric acid combined wit>hsodium metanilate, leaving one hydrogen on the nitrogen, \vas manufactured commercially for a large soap company. HowTever, the product proved deficient in foaming and detergency on cotton and wits withdrawn from the market. The choice of a metal for Ra may affect foaming and the power to emulsify and disperse other substances. There is little difference in solubility between the sodium and potassium salts in the Igepon compounds investigated. The calcium salts are much less soluble. Although one primary factor in determining which Igepontype compounds will be commercially important is the cost of raw materials, the economic limitations still permit a relat,ively wide area of investigation. Early in the investigation of the Igepon-type compounds it was decided that the product derived from oleic acid and N-methyltaurine provided the optimum combination of desirable properties. This compound is further recommended by the relatively low price of its raw materials. The product, sodium .V-(g-ortadecenoy1)-N-methyl taurate, commonly called oleoylmethyltaurine, has the structural formula:
Vol. 42, No. 9
accumulates on the kettles due to extended inactivity, it is driven off by introducing steam into the jacket while the kettle is empty. To begin the operation oleic acid is blown by air from a feed tank to a steel weigh tank; phosphorus trichloride is similarly blown into a lead-lined weigh tank. A 3927-pound charge of acid is drawn from the weigh tank and dropped by gravity into the kettle. Phosphorus trichloride (1010 pounds) a t room temperature is introduced from the weigh tank over a period of 1hour while cooling water is circulated through the jacket of the kettle. A sight glass in the lead line through which the phosphorus trichloride is charged permits the operator to judge the flow rate of this stream. After the kettle has been completely charged the temperature is raised to 50' to 52' C. and is held there for 6 hours by introducing 90-pound steam into the jacket. At the end of that period the temperature is raised to 60" C. for an additional 15 minutes to ensure completion of the reaction:
About 60% of excess phosphorus trichloride is used. This excess, about 375 pounds, is partially retained in solution in the fatty acid chloride and appears i n the final product as phosphite salt. The finished product is blown by air pressure into two leadlined cone-shaped tanks and allowed to stand overnight to settle out the by-product phosphorous acid. The bases of the cones are heated with external 1.5-inch lead steam coils to thin down the heavy acid sludge and aid in the separation. After drawing off t,he first waste acid the contents of the cone tanks are agitated and then a second separation of acid is drawn off. The point of separation is determined by observation through sight glasses in TI H 0 the drawoff lines. The H H H H H H H H I I H H H H I I H I I H O 1 I i I I I i I I I i I spent acid is piped direct H-&-A-A-A-C-C-C-C-~=c-~-c-c-~-~-~-~-~-N--I I /I to the sewer through lead I I I I ' I I I I I pipes traced with 1.5-inch H H H H I.1 11 ii H-4-HH H 0 I€ H H H H I II outside diameter lead H pipes carrying low pressure steam. Oleic acid chloride will decompose on standing if exposed to Its manufacture under the trade name Igepon T is described in atmospheric moisture. Consequently it is made up only as this article. needed and is piped through steam-traced lead lines direct from PRODUCTION OF IGEPON T the cone tanks to the weigh tanks of the Igepon unit. The yield from the acid chloride synthesis averages 4158 Igepon T gel and Igepon T powder comprise the major part pounds with an average analysis of: of General Aniline's production of taurine-derived surfactants. A clear liquid product, a slurry, a paste, a high density concentrated powder, and various special powdered Igepon prod% ucts are also made in minor quantities. The active ingredient Oleic acid chloride 90-92 of all these products is the sodium salt of fatty acid taurates. Free fatty acid (as oleic) 3.5-8.0 They differ in their concentration of active ingredient and in Phosphorus trichloride 2.54.2 the percentage of water and inorganic salts and in pH. Oleic Acid Chloride. The first step in manufacturing Igepoii T This represents 91% of theoretical. gel or Igepon T powder is the production of oleic acid chloIgepon T Gel. All the various types of Igepon T are made by ride (oleoylchloride) from oleic acid and phosphorus trichloride the same chemical reaction (the Schotten-Baumann reaction) : (Figure 1 and Table I). Acid chlorides other than oleic are sometimes used to make special Igepon compounds. The reaction takes place in a jacketed lead-lined kettle CH-(CHJ-CH, equipped with both cooling water and low pressure steam conH-N-(CH2)2-SOaNa NaOH 4 II nections. A horseshoe-type agitator stirs the charge. A I .5-inc.h CH-(CHS)-COCI I CHa lead vent to the roof of the building removes volatile nrid fumes and decomposition products of phosphorus trichloride ?H--(CH2)7-CHI I from the kettle. There are two such kettles in parallel a t Linden operating on independent batch cycles. It is essential CH(CH~)~-C-P--(CII~)t-SOBNa1- H20'+1NaCI that the kettle be dry before charging is begun to prevent hydrolysis of the phosphorus trichloride. If any condensation AH3
'LAI\
+
+
!
September 1950
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
1631
Minor changes in procedure yield products of various concentrations and physical states. The gel accounts for most of the production. This product is made in a brick-lined kettle equipped with a four-fingered stainless steel agitator. A stainless steel submerged coil provides temperature control. The kettle has stainless steel feed lines for oleic acid chloride and muriatic acid and caustic solution, a stainless steel thermometer well, and a lead vent pipe. Air for forcing the charge out of the kettle is introduced into the vent pipe. A stainless steel kettle, equipped with an anchor-t ype agitator is also available. Process temperatures in this kettle are controlled by a steel jacket connected to both steam and cooling water lines. Inlets and vents are arranged similarly to those in the larger kettle. To begin the batch 25 to 30% aqueous solution of S-methyltaurine is blown over from the storage tanks until an amount of solution equal to 875 pounds of N-methyltaurine has entered the neigh tank. The correct gross weight of this charge, based on the N-methyltaurine analysis of the storage tank, i s supplied to the operator by the analytical laboratory. This charge is then dropped by gravity into the reaction kettle, and the flow of cooling water is started in the jacket to bring the temperature of the charge down to 22O to 25" C. Water weighed in the same weigh tank is then added to bring the total weight of the charge a t that point to 12,000pounds. Addition of 30% aqueous caustic solution is begun and when the equivalent of 140 pounds of sodium hydroxide has been weighed in, oleic acid chloride is introduced from a lead-lined weigh tank. The caustic and Oleic Acid Chloride and Waste Phosphorous Acid Are Separated in acid chloride enter the kettle through separate Cone Tanks perforated stainless steel pipes below the level Heating coils and steam tracing can be seen on the tank being diacharged by the of the initial taurine charge. This practice operator: these have been removed from the tank on the ri$ht minimizes the liberation of noxious fumes, reduces the corrosive effect of the acid chloride above the liquid level, and safeguards against side reaction between sodium hydroxide and oleic acid chloslightly red spot test with brilliant-yellow paper (pH 6 to 8). ride. Simultaneous addition of the two reactants is conThis neutralization usually requires about 150 pounds of acid. tinued for 4 to 6 hours until a total of 425 pounds of sodium In making some of the special Igepon products additional hydroxide and 2100 pounds of about 92% oleic acid chloride muriatic acid is added a t this point. have been charged. The rate of addition of these two solutions In making the standard T gel the neutralized batch is diluted is adjusted to maintain a slight stoichiometric excess of sodium to 17,000 pounds with water and 7 pounds of a light, floral, hydroxide in the kettle at all times, as determined by spot tests on liquid perfume. The charge is then heated to 55" C. and held triazene paper- 2 44-nitro-O-tol yldia~oamino )-4-aulfobenzoic acid. there for 1.5 hours. After all the reagents have been added the charge is agitated The charge is blown into white oak, gum, or ashwood barrels. for an additional hour to ensure completion of the reaction. Air used to blow out the batch passes through a trap to remove Cooling water is circulated through the coils at maximum flow rust particles which would tend to darken-the finished product. rate during the entire reaction period. During the winter As a further precaution against contamination a 0.007-inch months the charge is about 22" C. at the beginning of the reacopening stainless steel filter on the product discharge line removes all solid particles from the liquid product before it enters tion and rises to 27" C. However, in the summertime the final the shipping containers. The barrels are allowed to cool on the temperature may go as high as 40" C. shipping platform, and when the Igepon reaches a temperature After the reaction has been completed a sample is taken and of about 40" C. i t sets up as a firm, opalescent gel. the percentage of excess N-methyltaurine is determined by Recently several experimental shipments of Igepon T gel coupling with diazotized m-nitraniline. It is desirable to have have been made in polyethylene-lined, fiberboard drums. Ala slight excess of N-methyltaurine in the product to ensure though these drums are more expensive than the wooden barrels that the reaction has gone to completion. they are easier to fill and to handle. Consequently, i t costs After completion of the reaction muriatic acid is added to the only about $4 to pack 50 gallons of gel in the fiber drum comkettle through a glass and rubber siphon from a 12gallon carboy pared to $6 for 55 gallons in a barrel. If further evaluation conmounted on a 2Wpound platform scale. The entire scale asf i r m the superiority of these containers they may supplant sembly is elevated by a windlass device to control the acid flow wooden barrels for shipment of Igepon T gel. through the siphon ( 4 E ) . Acid is added until the charge gives a
1632
INDUSTRIAL AND ENGINEERING CHEMISTRY
-3-
Igepon T Powder is Transferred in Drums from Spray Dryer to Hooded Mill Material is packaged for shipment directly from discharge of t h e mill
September 1950
INDUSTRIAL AND ENGINEERING CHEMISTRY
1633
The batch of gel yields about 17,000 pounds, having a composition of 15.3 to 16.3% oleoylmethyltaurine [sodium N-(9-octadecenoy1)-Nmethyltaurate], 0.8 to 1.0% sodium oleate, 0.14% N-methyltaurine, 4.0% sodium chloride, and 78% water. This represents approximately the theoretical yield. Igepon T Powder. The second most important Igepon T product is the standard powder. In manufacturing this product the initial charge of 30% N-methyltaurine solution contains 930 pounds of 100% N-methyltaurine, and when diluted with water to 12,000 pounds it gives a slightly more concentrated solution than that used in the gel process. As a 30% solution 172 pounds of sodium hydroxide are added to this initial charge to keep the reaction misture on the alkaline side. Then 2220 pounds of technical oleic acid chloride are added simultaneously with 295 pounds of sodium hydroxide as a 30% solution over a period of 4 to 6 hours, aa in the gel production. The batch is stirred for 1 hour after charging is completed and any excess N-methyltaurine is reacted with additional acid chloride and caustic soda as in the production of gel. T h e completely reacted charge is then heated to 50" C . by the steam coils and neutralized to the brilliant-yellow end point with muriatic acid. Immediately after neutralization 5200 pounds of common salt are dumped into the batch from bags, and water is added to bring the total weight of the batch to about 26,000 pounds. At this concentration, about 36% solids, the salt is completely dissolved. It is important that no suspended solid material remains in the charge because i t would plug Condensation Kettle and Oleic Acid Chloride a n d M e t h y l t a u r i n e up the nozzles of the spray dryer. If the pH of Weigh T a n k s the batch after the addition of the salt does not fell between 7.1 and 7.3, sodium hydroxide or Operator is cheoking the batch for alkalinity with indicator paper muriatic acid is added to adjust the pH within theae limits. The salbloaded mixture is blown from the reaction kettles control. A high-silicon iron pump ( I E ) ,drawing from the tank, into a 3/pinch lead-lined steel feed tank. The charge is heated recycles water to the spray nozzles and supplies process water to 50" C. by lead steam coils in the feed tank and then is pumped to the condensation kettle. to the three 1Ggallon feed pots of the spray dryer (Figure 2). If a kettle batch is made each day the dryer feed pots can be The dryer atomizers use air at 80 pounds per square inch kept full and provide an uninterrupted feed to the dryer. Under pressure heated to 220" to 225" C. by a steam coil heat exthese circumstances the dryer can handle as much as 360 to 400 changer, The relatively high feed pressure is necessary to mainpounds of Igepon per hour, as i t has a rated capacity of 770 tain 50 pounds pressure a t the injection nozzles to ensure adequate pounds of water per hour. atomization in the tower. Air supplied to top of the dryer is The product comes from the dryer as low density granules preheated to about 225' C. by an oi1:fired furnace and forced which are lightly milled in a paddle mixer to break up the larger into the dryer by a centrifugal fan a t a rate of about 250 cubic lumps and to mix in 500 grams of a light floral perfume per ton feet per minute. The major part of the dried powder is disof Igepon. From the mill the powder is dropped directly into charged from the bottom of the dryer tower and carried along by the open-top steel drums in which it will be shipped. the added cold air into the primary cyclone separator from which Yields of powdered product run around 8200 pounds per batch i t drops directly into a transfer drum. About 10% of the and analyze about 30.5 to 32.5% oleoylmethyltaurine, 1.5 to product, however, is carried through the cyclone and is reintro3.0% sodium oleate, and 0.14 to 0.8% N-methyltaurine; the duced into the dryer chamber. A second take-off from the dryer remainder of the powder comprises inorganic salts. Chief among chamber is located just above the bottom taper. This duct these is sodium chloride and a trace of sodium sulfate. However, carries a more dilute stream of air-borne powder into a larger, phosphite salts (about 3%) are also present; these are formed secondary cyclone separator. The solids which fall out in this from the excess phosphorus trichloride dissolved in the oleic acid separator are refluidized by more cold air and returned to the top chloride. The yield is about 91% of theoretical. of the primary cyclone. The overhead from the secondary RAW MATERIALS cyclone, containing 7 to 10% of the product, is introduced into a water scrubber. One water spray above the inlet and three Oleic acid for the production of oleic acid chloride is delivered below remove all but about 2% of the product from the dryer either in steel tank cars or tank trucks from which it is blown by exhaust. The scrubbed air is vented to the atmosphere. The air pressure to a 9000-gallon steel storage tank inside the producliquor is drawn from the bottom of the tower into a storage tank. tion building. T h e tank is made of 0.5-inch welded plates. A Make-up water is added to this tank by an automatic level feed tank is filled from the storage tank by gravity; it holds 550
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
1634
Vol. 42, No. 9
TO CONDENSINGKETTLE "
IGE PO N T"SOLU1lON
OVERFLOW TO
I -
1 I
1
'
P~EHEATER .
I
w I
I
WATER
c
Figure 2.
gallons and is built of 0.5-inch carbon steel. This tank is of more recent construction and is tested to withstand 45 pounds per square inch pressure so that the transfer of oleic acid from it to the weigh tanks can be made by blowing with air. This intermediate tank eliminates the necessity of subjecting the main storage tank to the pressure required for pneumatic transfer. I t is extremely important that a high quality of oleic acid be used in this process. If an excessive amount of esters or unsaponifiable material is present the resultant Igepon will have an excess of free fat which tends to make the gels cloudy. General Aniline's acceptance specifications for oleic acid are as follows: Titer, O C. Cloud point C. Color (Lovibond 1-inch Column Red) Saponification No. Acid No. Iodine No. Free fatty acid (as oleic), % Unsaponifiables. %
4-6
3.3-6.7 5-8
196-199 195-198 90-93 98-99.5 2,0-3.5
Phosphorus trichloride is obtained by lead-lined tank car. Cars are unloaded by air pressure into a 6100-gallon homogeneously lead-lined storage tank located outside the operating buildings for safety reauons. This tank of 0.5-inch carbon steel is fitted with a 2-inch lead vent and a lead line connecting it to a weigh tank of similar construction. Phosphorus trichloride is held to the following specifications: Color Turbidity Assay (PCla) Distillation range Free PL Di&illation residue
Water white None 99.5% First 99%, 74.5-78.0°C None 0 5%
Spray Dryer
The N-methyltaurine used in the Igepon T condensation reaction is manufactured by the intermediates department of the General -4niline Works at Linden (9). It is delivered as a 25 to 30% filtered aqueous solution to the Igepon T area by a 2700gallon steel tank trailer. The 30 and 50% caustic soda solutions and the muriatic acid used to control the pH of the batch a t various points in the processes are obtained as standard commercial products from various suppliers. These are usually delivered to the plant in tank cars although they may be received in tank trucks. Both the acid and alkali are stored in central storage tanks that serve other processes in the works besides the Igepon T operations. The alkali is piped to intermediate storage tanks in the Igepon area. The acid, which is used in relatively small quantities, is drawn off into 12-gallon carboys which are trucked to the Igepon kettles. CHEMICAL CONTROL
Chemical control on the Igepon T operation is relatively simple. During many years of processing experience, General Aniline has accumulated rule-of-thumb knowledge which tells the operators whether the reaction is going properly. At some points analytical samples are taken merely as a precaution and only analyzed if trouble develops later in the operation. The phosphorus trichloride used for the production of the oleic acid chloride is generally arcepted on the manufacturers' shipping analysis. Only spot checks are made of this material at about 3month intervals. Every shipment of oleic acid, however, is analyzed against the specification given in the preceding section. A complete analysis is submitted by the intermediates depare
September 1950
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INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
TABLE11. SERVICEREQUIREMENTS Process Oleic acid chloride Ieepon T gel powder
a:gn$'
(Per batch) Electric Power, Kw-Hr. Steam, Lb. 6000 50 9000 330 1250 27000 130 I . .
Water", Cu. Ft. 160 1200 800
...
1 Includes both process and cooling water. Also sometimes b When ground and perfumed for direct consumption. used to blend two or more batches to give uniform product.
ment with each delivery of N-methyltaurine. Only the Nmethyltaurine content figure of this analysis is checked by the Igepon operating section. From this figure the weight of the initial N-methyltaurine charge to the kettle is calculated. Samples for this check are taken both from the tank wagon and from the storage tanks. As an added precaution another sample is taken from the reaction kettle after the N-methyltaurine has been introduced and diluted with water. This sample is only analyzed if trouble develops later in the process. The acid chloride charged to the reaction kettle is analyzed for oleic acid chloride, phosphorus trichloride, and free fatty acid. After the condensation is complete the batch is checked for pH and residual N-methyltaurine, The pH is checked by a standard calomel-cell pH meter and is then adjusted as explained in the operating procedure. After the pH has been adjusted it is checked again, and the final shipping sample is sent to the laboratory. This final sample is examined for clarity, viscosity, and alkalinity. A 10% water solution of this sample must be perfectly clear and must have a pH between 7.2 and 7.5 at this point. The Igepon T powder undergoes an almost identical analysis routine. If ita content of oleoylmethyltaurine falls outside of the permissible limits i t is blended into subsequent batches at the ribbon blender. UTILITIES
t
Since the Linden Works is a highly diversified operation involving a multitude of small capacity process installations, i t is most economic to provide centralized utility installations to service all the individual plant areas. Steam is produced in a central powei plant and made available throughout the plant a t both 90 and 450 pounds per square inch gage pressure. In the I g e p n process steam is used only for process heating (Table 11). Since the temperatures required are all reasonably low, only the low pressure steam is required for this operdtion. All pumps and other auxiliary machinery are electrically driven. The motors run on 220-volt current supplied by a central steamdriven generator; 110-volt current is available in the operating buildings, but i t is used for lighting only. Compressed air is supplied by central compressors located in the power house. Separate lines carry 45- and 110-pound-persquare inch air throughout the plant. Since the Igepon operation requires air only for forcing liquids from one vessel to another, the 45-pound air is su5cient. This pressure produces a lift of about 100 feet for the liquids handled and even over considerable distances is adequate for the requirements of the process. In other parts of the plant the 110-pound air is used primarily for air-driven machinery and tools. The air used for transferring phosphorus trichloride is passed through a dryer and filter to prevent hydrolysis and contamination. The purifying unit consists of a liquid trap, a steel chamber 12 inches in diameter and 6 feet long filled with quicklime to dry the stream, and a similar tank 4 feet long containing a cloth bag filter to remove any particles of lime or other solids that might be carried over into the phosphorus trichloride tanks.
Polyethylene-Lined Lever-pak Drums Are Being Tested to Replace Wooden Barrels for Shipping Igepon T Gel The spray dryer has its own compresser which provides 90pound-per-square inch air for atomization. This compresser was installed before the distribution lines from the central air supply were extended into the Igepon process building. Since the dryer is designed to use 90-pound air the independent compresser has been kept in service. An unusual combination of circumstances operating a t the Linden Works make the water supply situation there almost unique. The plant site is a low point of land extending out into Arthur Kill, a brackish arm of the sea, characteristic of the topography of the northern New Jersey coast. The water in this inlet analyzes from 7000 to 19,000 p.p.m. of chloride and from 14,000 to 20,000 p.p.m. of total dissolved solids. It has an average specific gravity of 1.015 as compared to 1.025 for sea water. A typical analysis might run: Chloride Magnegium Calaium Sulfate Alkalinity (as CaCOs)
P.P.M. 15,000 637 254 1,253 85
This brackish water, about one third as salty as sea water, is used for most cooling purposes in the Linden Works. The original decision to use salt water for cooling purposes was influenced by several factors in addition to its easy availability. The land point on which the works stand is occupied only by the chemical plants that grew out of the Grasselli Chemical Company. Fresh water for these plants is furnished by the municipality of Elizabeth, N. J. A single 14-inch line reaches out from the town of Linden to supply these works. This arrangement makes the
INDUSTRIAL AND ENGINEERING CHEMISTRY
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Vol. 42, No. 9
TABLE111. REPRESENTATIVE TYPESOF IGEPON T CURRENTLY MANUFACTURED Product Name (General Dyestuff Corp.) Igepon T N Gel Cyclopon GA Ex
Product Name (General Aniline & Film Corp.) Antaron L-113 Antaron L-217 Antaron L-114
Igepon T Gel Igepon T Gel Clear I epon T P Gel yclopon A Ex
c'
Antaron L-110 Antaron L-215
Igepon TC Igepon TL Clear Igepon NF"
Formula AG Antaron L-520
Igepon T Slurry Igepon T Paste Igepon T Powder Cyclopon A Ex
dntaron Antaron -4ntaron Antaron
I epon LM Conc. c' yclopon A Powder High Conc
Antaron L-455 -4ntaron L-205
Igepon TFS Conc. a Patent pending.
Antaron L-177
L-121 L-130 L-135 L-245
Raw Materials Fatty Acid Taurine Oleic N-methyl N-me t hyl 80 Palmitic 20 Oleic ."-me thyl Oleic N-methyl Oleic N-methyl Oleic N-methyl 80 Palmitic 20 Oleic Coconut N-methyl Oleio N-me thy1 Palmitic N-cyclohexyl N-methyl Oleic N-me thyl Oleic N-methyl Oleic 80 Palmitic N-methyl 20 Oleic Lauric N-methyl N-methyl 80 Palmitic 20 Oleic N-methyl Oleic
fresh water expensive and General Aniline officials believe that it would be impossible to obtain any appreciable amount of additional fresh water from the water district at any price because of inadequate supply. The cooling salt water intakes are located 24 feet below mean water. Temperatures at this depth are consistently low which improves the cooling efficiency of the water and eliminates the introduction of marine algae into the cooling systems. On only one occasion has the plant been troubled with marine growth inside cooling equipment. This occurred during a period of extreme turbulence a t the intakes caused by nearby dredging operations. The salt water intakes are protected by 16-inch-mesh rotary screens which are kept clean by water sprays. Other screens located in the various processing areas of the plant provide additional protection against the introduction of solid matter into the process equipment. An average of 5000 gallons per minute is taken through the intakes. However, during the summer this volume may rise to as much as 9000 gallons. The chemical composition of this cooling water is such that its corrosivity has not proved as great a problem as its tendency to form a heavy adherent scale. To allow for this scale formation all cooling equipment in the plant has been intentionally overdesigned. Performance data give an index of the decrease in heat exchange efficiency in such equipment as scale accumulates. When performance characteristics drop to predetermined empirical levels the coils or jackets are taken out of service and cleaned. Generally such cleaning is required only every 1.5 or 2 years. However, the cleaning must be done by mechanical means since the type of scale formed cannot be dissolved by ordinary acid or alkali cleaning techniques. The use of once-through salt water instead of recirculated cooling water has another advantage for the Linden operations. Many of the waste effluents from dye and intermediates synthe'ses a t the plant would normally present a serious waste disposal problem. However, under the present arrangement all liquids, process effluents, or cooling water are collected in a common sewer and returned to the kill. The large volume of used cooling water introduced into this sewer so dilutes the combined effluent that it is not necessary to treat the waste liquor before it is discharged. MATERIALS OF CONSTRUCTION
The corrosion problem is not critical in the operations described, but some special materials must be used. Carbon steel is suitable for most vessels. However, those which must contain phosphorus trichloride or oleic acid chloride are homogeneously lead-lined. This type lining is applied by tinning the entire inner surface of the steel vessel and then soldering the lead
%
Active 13.5 13.5
Descriptive Data Gel: pH 5 % soln., 7-7.5 Dense powder, cut with sodium sulfate
15.75 15.75 15.75 15.75
Gel: pH 5% soln., 7-7.5 Clear gel: pH 5% soln., 8 Soft gel: p H 5% so!"., 6.676.8 Dense powder, cut with sodium sulfate
22 25 28
Paste Rlurry Clear liquid Paste, nonfoaming
28 31.5 31.5 48
Cloudy liquid Paste Fluffy powder cut with sodium chloride Dense powder: cut with sodium sulfate
60
65
Dense powder Dense powder
72.5
Dense coarse powder
lining plates to the whole steel surface. This technique eliminates the problem of buckling and blistering. I t also means that in the event of failure of the lining only the steel directly behind tho gap in the lining is attacked. In the so-called "loose-lining" technique in which the lead sheets are tacked to the shell only along the seams, a failure at any one point usually means that the corrosive contents of the vessel will shortly enter the entire space between the lining and the vessel wall. Actually, the spray dryer feed tank at Linden is lined in this fashion, but only moderate temperatures are encountered in this tank and the agitation is never violent. The lead linings in the Igepon process equipment last 7 to 9 years before they must be replaced. The newest of the two Igepon reaction kettles is made of stainless steel. This kettle has proved satisfactory, and any future kettles installed for this step will be this type. However, the older kettle, lined with common glazed floor tile has given fairly good service, although as in all brick-lined kettles, the mortar is the weak point from a corrosion point of view. This brick lining requires pointing about every 2 years. All equipment which comes in contact with finished liquid Igepon is made of stainless steel, since the detergent will exchange cations with ordinary steel to form the iron salt which has an undesirable dark color. Submerged steam lines in the brick-lined kettle are stainless steel; in the spray dryer feed tank these are lead. The other kettles are equipped with external jackets. Agitators are either lead-covered, stainless steel, or in the case of the old spray dryer feed tank, wooden. Neither stainless steel nor lead will stand up in the duct which carries the moist exhaust from the spray dryer. Nickel is currently used for this service although tests indicate that a high nickel alloy (ZE,3E) would serve as well. The spray dryer itself is made of plain carbon steel. Tanks which must withstand static pressure such as those employing air pressure transfer are entered and inspected, and subjected to hydraulic testing every 2 years. Unpressurized steel tanks which store corrosive liquids are on a similar inspection schedule. Storage tanks in noncorrosive service are inspected every 5 years. Kettles are also inspected a t 5-year intervals. Jacketed kettles are lifted out of their jackets, and the surfaces are cleaned and inspected for pits. Pits usually occur in the welded seams. If the welds are badly pitted below the surface of the adjacent plates the bead is chipped off and the seam rewelded. Pumps. Since most of the materials involved in the Igepon process are transferred through the plant by air pressure, pumps present only a limited corrosion problem. Where pumps are used they are of motor-driven centrifugal type. Where pure oleic
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INDUSTRIAL AND ENGINEERING CHEMISTRY
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acid must be pumped, a high alloy steel (6E) pump is used. All other pumps are of carbon steel. Valves and Pipe. Stainless steel valves are used on all lines which transfer finished liquid Igepon T. In the past other flows have been controlled by lead-lined plug valves. However, as these valves are retired from service they are being replaced with high chrome alloy gate valves (6E). Pipe lines which carry liquid Igepon T also are of stainless steel. Those which transfer oleic acid chloride are lead-lined and steam-traced. The steam tracing is only used in the winter when the acid chloride has a tendency to thicken and move sluggishly. NEW PLANT 3
Construction is just beginning on a new plant to replace some of the facilities described in this article. Additions are being made to an existing new building which will ultimately house the manufacture of Igepon T gel, an Igepon T liquid which has just recently been submitted to the market, and a slurry form which is now in the process of market introduction. The processes employed in the new installation will be identical to that now in use. The two reaction kettles and all piping and equipment which will handle the fipished Igepon will be made of stainless steel. The new facilities will accommodate only the final step of the Igepon production. N-methyltaurine will continue to be made by the intermediates department of the company and the oleic acid chloride will be produced in the equipment now used for that purpose. IGEPON T PRODUCTS
Igepon T finds its greatest use today in the textile field where it was first introduced. The approximately 65% of sales that go into this industry find their way into almost every phase of testile wet processing. The list of uses include scouring, wetting out, degumming, kier boiling, dye leveling, dye pasting, chlorine and peroxide bleaching, fulling, lime soap dispersing, and finishing. Agriculture, paper, leather, and metal cleaning consume most of the remaining 35% of sales. Small amounts of Igepon T go into household products, including dentifrices, shampoos, cosmetics, and pharmaceutical preparations. I t is also used in the scouring of feathers, in electrolytic plating baths, in the washing of automobiles, airplanes, railroad coaches and locomotives, rugs, floors, buildings, and for cleaning streets and roads, and in the dairy, food, and fur industries. Shortly after General Aniline began production of Igepon T i t was discovered that the product could be produced in gel form. The optimum surfactant concentration for gelling was near one half that of the standard paste or powder so that when this product wm ultimately marketed its strength was standardized a t 15.75% oleoylmethyltaurine for the sake of uniformity and ease in accounting practice. The second year the gel was on the market its sales exceeded those of the paste form and i t has continued to supplant that product until paste sales are now almost negligible. In 1942 Igepon TFS was introduced largely in response to a request by the Navy for a powder of high active concentration for use aboard ship and for shipment to advance bases. The product developed to meet this demand contained 72.5% active ingredient. In the last 2 years of World War I1 the Navy shifted over to the standard powder. However, by that time the TFd had begun to find a civilian market and was retained in the line of Igepon products. General Aniline has developed two new forms of Igepon T which are now ready for the market. One is a clear liquid suitable for incorporation into consumer products. It looks much like a conventional liquid soap and is available with 15 and 25% active ingredients. The newest of the products is called a “slurry” although it more nearly resembles an opaque heavy liquid. This material
Phosphorus Trichloride Is Stored Outside the Processing Building as a Safety Precaution contains 28% active ingredient and is essentially the product as i t comes from the condensation kettles; it contains no added chemicals. The material is intended primarily for formulators who will process it further by adding it to other ingredients or drying it to a powder. It can be shipped in tank cars and is the least expensive of the various Igepons. As of last spring General Aniline made the primary reactant of Igepon T, N-methyltaurine, available to the general public. This compound has never before been commercially available in this country. Since the basic patent on Igepon is about to expire, other organizations may undertake the manufacture of fgepon-type products. In this event General Aniline can supply the manufacturers with N-methyltaurine and other taurine derivatives. There is, of course, one restriction. The would-be manufacturer must use a new name for his surfactant. The name Igepon is registered by the General Dyestuff Corporation, an independent organization selling General Aniline’s dyes and surfactants. Not even the General Aniline company itself may use the name when i t makes a sale through its own sales department. The product then becomes Antaron, a trademark of General Aniline’s Antara division (Table 111). Thus Antaron L-114 is Igepon T gel, Antaron L-130 is Igepon T paste, Antaron L-13,5 is Igepon T powder, and Antaron L-177 is Igepon TFS High Conc. The Igepon T series using oleic acid and N-methyltaurine as starting materials must not be confused with the Igepon A series which is made from oleic acid and hydroxyethanesulfonic acid. The Cyclopon A series of products are Igepon T types made from palmitic acid and N-methyltaurine. Igepon N F is also a taurine-
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taurine-type Igepon (Table IV) can be modified to well over TABLE IV. INVERSE WETTINGSTRENGTH OF TAURINE-TYPE 1000 varieties. Any one of the various detergent properties may IGEPON IN DISTILLED WATER be obtained to a high degree by making changes in the struc-
(Draves wetting tests: 25-second sinking time at 25O C.; 3.0-gram hook) Igepon Sodium N-2-ethylhexano 1 N n butyl taurate Sodium N-octanoyl-N-n-i;tyi &urate Sodium N-2-ethylhexanoyl-N-cyclohexyl taurate Sodium N-heptanoyl-N-n-octyl taurate
Active Material Reqd., Grams/Liter >7.50 >5.00
10.00 0.49 0.29 0.61 0.84 0.19 0.16 0.21 6.75 0.30 9.50 2.50
0.62
0.50 0.41 0.38 0.21 0.18
0.26
0.33
0.28 0.46
