March, 1929
IAVDCSTRIAL A S D ESGI,VEERISG CHEXISTRY
proteins, and miscellaneous amino acids, diluted with sodium salts. Cost of Treatment
ACID-CRz4CKING-SinCe the main bulk of the liquors come in the afternoon, this is estimated a t 40 pounds of 66" B6. acid per 1000 gallons, or $18 per day. ACID-CRACKIKG FOLLOWED BY ALUMIKlJhf SULFATE C O AGULATION-This, based on adjustment of the pH with 60 pounds of lime and addition of 60 pounds of aluminum sulfate per 1000 gallons, gives a cost of $74 per day. ALUMIKUM SULFATE COAGUL.4TION AIiD ALUhfINUhl RECovERY-The primary reaction is assumed to be as follows: 6NazCOs
+ Alz(S04)a = 6NaHCOa + 2Al(OH)a + 3NazSO.1
From the amount of sulfuric acid required, about 85 pounds of sodium carbonate or its equivalent as soap must be present per 1000 gallons. This will precipitate the aluminum from 85 to 90 pounds of aluminum sulfate. Excess lime must be used for the balance. As a conservative figure we are assuming the use of 160 pounds of aluminum sulfate per 1000 gallons, which gives the following requirements: 360 Ibs. aluminum sulfate t o make up 5 per cent loss in recovery 1500 Ibs. lime for precipitation of excess aluminum 3750 Ibs. 66' Be. sulfuric acid for aluminum recovery including 10 per cent excess 215 Ibs. lime for neutralization of excess acid
$5 40 7.50 37.50
_-1 . 1 0 $51.50
This may be subject to reduction by 25 per cent if the process can be operated with 120 pounds of aluminum sulfate, or by 50 per cent if filtration a t 80 pounds of aluminum sulfate per 1000 gallons can be satisfactorily worked out. Estimated Value of Products and Cost of Production
Typical wool washings contain about 1.1 per cent of wool grease and upward of 0.3 per cent of free fatty acid as soap. Assuming final recovery to be 90 per cent of the total, with crude degras a t 3 l / 2 cents per pound (the price varies from 3.5 to 5.0 cents per pound in carload lots), the recovered material would be valued a t $166 per day. Against this the cost of production, including containers, interest a t 8 per cent, and amortization a t 10 per cent, is estimated a t $111.20 with ground rental and taxes not included.
213
It should also be possible to dry the sludge and extract a good grade of lanolin without appreciable fatty acid content. The residue from extraction could then be decomposed with sulfuric acid to give aluminum sulfate for coagulation, and free fatty acid, or it could be discarded, depending on economic factors. This procedure was not investigated. Potash recovery after recirculation also shows an estimated profit. The potash recovery process is not an essential part of the grease recovery system. The results quoted herein are incomplete in a number of ways. This is due to depression in the woolen industry, which caused a partial shutting down of the plant being investigated, while these data were being obtained, followed by a complete shutdown, which terminated this work. Summary
The cracking of wool washings with acid was investigated and led to the conclusion that this method alone cannot be used for complete purification. Coagulation with aluminum sulfate proved entirely satisfactory for operation on a 1 per cent basis. This yields a sludge containing lanolin mixed with aluminum hydroxide, aluminum soap, fine dirt, and albuminous matter. Decomposition of this sludge with acid was investigated by another laboratory with satisfactory results. The sludge from aluminum sulfate coagulation can be filtered in plate-and-frame filters, but vacuum filtration is preferable. Recovery of potash salts after recirculation of the wash water appears economically possible. After dilution with circulating water this effluent is suitable for discharge into a stream of moderate flow. Acknowledgment
The results given in this paper were obtained in coeperation with Gerald W. Knight, consulting sanitary engineer of Passaic, N. J. They are published by permission of the Passaic Worsted Spinning Company. The major portion of the laboratory and semi-plant work was carried out by Donald S. Bruce.
Relation of Composition to Properties of Lacquer Solvents' Robert Calrert VAN SCHAACK BROS. CHEMICAL WORKS,CHICAGO, ILL
M
AKY new solvents for use in lacquer have been discovered recently, some in industrial and others in university laboratories. The professor as well as the lacquer chemist may ask, therefore, what the requirements are for such a solvent and whether success or failure in meeting those requirements can be forecast tentatively from the formula for the compound. A solvent for use in lacquer should have a satisfactory cost, rate of evaporation, odor, and color; be free from discoloration; dissolve pyroxylin; dissolve resins or, a t least, not precipitate them in the film; and hydrolyze slowly or not a t all under the conditions of use. Certain generalities are stated here that have been found 1 Presented before the Institute of Chemistry of the American Chemical Society, Evanston, Ill., August 8, 1928.
helpful in predicting whether a given substance will meet the last three important requirements. Solvent Power for Pyroxylin
On the basis that like may dissolve like, it is interesting to ,note the composition of pyroxylin. Irvine,l,* Hibbert,2 and others have shown that cellulose contains ether and alcohol groups. Hibbert's cellulose unit is CH-CH
I \ - ,
(CHZOH)-O-
I
v\ CHOH-CHOH-CH-
* Numbers in text refer t o bibliography a t end of article.
INDUSTRIAL AND ENGINEERING CHEiMISTRY
214
On nitration this would give, theoretically, a mono-, di-, or trinitrate. Actually, we get mixtures. The dinitrate of the possible formula CH-CH(CHz.ONOZ)-% O '
I
\
CHOH-CH.ON0-CH-
Vol. 21, No. 3
Solvent Power for Resins
Unfortunately, a solvent for use in lacquer must be compatible not only with pyroxylin, but also with resins. A solvent of wide application should go well with all the resins, including dammar and ester gum. Dammar, according to Dieterich,6 contains the ingredients shown in Table 111.
contains 11.1 per cent of nitrogen and corresponds almost exactly to the degree of nitration of certain types of pyroxylin. Table 111-Ingredients of D a m m a r The pyroxylin used in lacquer contains more nitrogen and AMOUNTAPPROX. OXYGEN COMPOCND IN DAMMAR CONTENT corresponds t o the formula [C~H,.,,O,.,~(ONOz)z.,,l,. Such Per cent Per cent a compound contains approximately 12 per cent of nitrogen, Dammarolic acid, CsrHn03(COOH)z 23 13 a-Dammar resene, CuHliO 40 10 58 of oxygen, and only 30 of carbon and hydrogen together. &Dammar resene, CaiHaaO 22 4 Equally conspicuous with the high percentage of oxygen Miscellaneous 15 is the presence of e s t e r , ether, and alcohol groups. Likewise, ester gum (the ester of glycerol with rosin) It should not be surprising, Pyroxylin of the grade commonly used in lacquer has a low percentage of theref ore, that p y r o x y 1i n contains approximately 58 per cent of oxygen. Many oxygen. Thus glycerol trisolvents of present commerresins, on the other hand, consist principally of carbon c i a l i m p o r t a n c e are oxyabietate, (C 19 H29C0 0 )3 and hydrogen with only a small proportion of oxygen. C3H5,13 contains only 10.2 compounds containing usuAn increase in the percentage of oxygen, within a per cent of oxygen and as ally either a carbonyl group, homologous series of solvents and within limits, inmuch as 89.8 per cent of hyas in an ester or a ketone, creases the solvent power for pyroxylin and decreases drocarbon. or a n a l c o h o l and ether the compatibilitJ with certain resins. Pyroxylin solIf like dissolves like, these group, as in the mono-ethers vents of abnormally high effectiveness (as measured resins of low percentage of of ethylene glycol. by dilution factors) frequently cause precipitation of oxygen should be most soluMore interesting is the resins in a lacquer film. Conversely, many precipible in an entirely different change in solvent power (as tants of pyroxylin, such as toluene or naphtha, are group of substances from measured by toluene diluexcellent solvents for ester gum or dammar, in acthose that dissolve pyroxytion factor) with change in cordance with the theory that like dissolves like. lin, with its high content of percentage of oxygen within An ester of a strong acid may be expected to hydrolyze oxygen. Such is the case. a given homologous series. more rapidly in a lacquer than an ester of the same alA c t u a l p r e c i p i t a n t s of In several series of solvents cohol with a weaker acid. pyroxylin, such as hydrowhich have been s t u d i e d carbons, are among the best there is a decrease in solvent s o l v e n t s for these resins. power, as might be expected, as the percentage of oxygen becomes farther from that in Conversely, we find frequently that the best solvents for pyroxylin are precipitants of resins in lacquer films. For expyroxylin. This is evident from Table I. ample, three compounds of very high solvent power for pyTable I-Effect of Proportion of Oxygen on Solvent Power for Pyroxylin roxylin that are now offered commercially are more or less inTOLUENEDILUTION compatible with certain resins. These are the newer, twoSOLVENT OXYGEN^ FACTOR^ P e r cent type solvents. Each of these compounds contains a hydroxyl 36 3.7 (Brown3) Ethyl acetate group. While this appears to be an advantage in dissolv28 2.2 Ethyl butyrate 10 0.0 Ethyl stearate ing pyroxylin, which also contains a hydroxyl group, it seems 28 2.9 (Browns) n-Butyl acetate to be a decided disadvantage with resins that contain chiefly 24 2.3 (Brown') n-Butyl propionate 9 0.0 n-Butyl stearate carbon and hydrogen. 36 3.7 (Brown*) Ethyl acetate It was R. H. Van Schaack, Jr., who first pointed out to 28 2.9 (Brown') n-Butyl acetate 24 2.2 (Brown9 the writer that a solvent for certain resins should be preferably n-Amyl acetate 35 6.2 (Davidson4) Ethylene glycol monoethyl ether low in oxygen. The applicability of this statement to com27 4.0 (Davidson') Ethylene glycol monobutyl ether 24 3.0 (Davidson') Ethylene glycol monoisoamyl ether patibility with ester gum, for example, is shown in Table IV. o
Approximate figures.
Many apparent exceptions to these trends may be cited. For example, glycol diacetate contains a higher percentage of oxygen than ethyl acetate but has a lower toluene dilution factor. Likewise, the monomethyl ether of ethylene glycol contains a higher percentage of oxygen than the monoethyl ether but has a lower dilution f a c t ~ r . Also, ~ formates may be poorer solvents than the corresponding acetates. Perhaps a proportion of oxygen higher than a maximum is undesirable in certain series of solvents. Finally, the structure has'an important effect, as will be seen from Table 11. Table 11-Effect of Structure on Solvent Power for Pyroxylin of Compounds Containing Approximately t h e S a m e Percentage of Oxygen SOLVENT sec-Butyl acetate n-Butyl acetate Ethyl butyrate Butyl ether of ethylene glycol o Approximate figures.
OXYGEN. Per cent 28 28 28
27
TOLUENE DILUTION FACTOR& 2.0 2.9 2.2 4.0
(Browns) (Davidson')
Table IV-Effect
of Proportion of Oxygen in Solvents on Com-
Ethyl acetate Ethyl glycolate Ethyl propionate Ethyl lactate Ethyl n-butyrate Ethyl n-oxybutyrate Ethyl acetate Ethyl acetyl glycoIate Glycol diacetate
patibility w i t h Ester G u m CH3.COO.CzHs HOCHz.COO.CzH6 CHJ.CHZ.COO.CZH~ CHs.CHOH.COO.CzHn CHa.CHz.CHz.COO.CzHs CH3.CHOH.CHz.CO0.CzH6 CHs.COO.CaHs CHz(CH3COO).COO.CzHa CH~.COO.CZHLOOC.CH~
Satisfactory Unsatisfactory Satisfactory Unsatisfactory Satisfactory Unsatisfactory Satisfactory Unsatisfactory Unsatisfactory
It may be argued that the introduction of an oxygen atom alone into ethyl acetate, propionate, or butyrate introduces a new kind of group, the hydroxyl group that was not present in the original ester. This is true. There are other cases, however, in which an increase in oxygen-containing groups of the same kind as originally present leads to incompatibility with the resin. For example, the introduction of a second acetate group into ethyl acetate in place of one hydrogen, in either the acyl or alkyl group, results in incompatibility
216
I N D U S T R I A L AND ENGINEERING CHEMISTRY
March, 1929
with ester gum or dammar, as in the case of the compounds under some conditions, might cause a deviation from this ethyl acetyl glycolate (CH3CO0.CH2.CO0.C2H5) or glycol order. Thus, it is not expected that methyl, ethyl, and diacetate (CH3CO0.CH2.CH2.00C.CH3). butyl esters of a given acid would hydrolyze a t exactly the Another indication that a low percentage of oxygen is de- same rate. sirable in a resin solvent is the statement of Davidson‘ that An allied study has recently been made by Williams, Gathe solubility of resins, oils, and gums in the glycol ethers briel, and Andrews.8 They believe that the percentage of increases somewhat with rise in the boiling point of the etheracid in eauilibrium with the ester is greater the stronger the that is, with decreasing percentage of oxygen. acid. In-other words, the equilibrium constant &)-of the If too high a percentage of oxygen is undesirable in a sol- reaction RA HOH ROH HA increases with the vent for a resin, then blending of an incompatible solvent constant of ionization MA)of the acid liberated by the hYwith a substance of a very low oxygen content or oxidation drolysis. Some of their data are shown in Table VI. of the resin should be useful expedients. Each of these Table VI-Hydrolysis of Esters of Fatty Acids has been suggested. Keyes12 points out the necessity of ACID KE K A x 10-6 adding a hydrocarbon to blend mastic, dammar, sandarac, Formic (ethyl ester) 1.45 21.4 Acetic (ethyl ester) 0 296 1.8 or kauri with a pyroxylin solution in certain oxygen-conPropionic (ethyl ester) 0 289 1.3 taining solvents. Brown6 mixes diacetone alcohol with HerFormic (methyl ester) 1.03 21.4 Acetic (methyl ester) 0.224 1.8 cosol to prevent resin precipitation. Likewise, butyl stearate Propionic (methyl ester) 0.214 1.3 or dibutyl phthalate9 may be used t o blend resins with an otherwise incompatible solvent. On the other hand, oxidaA larger degree of hydrolysis of a n ester does not mean tion of ester gum has been described as a means of making per se a faster rate of hydrolysis. However, a strong acid i t compatible with one of the newer solvents. Finally does react quickly with an alcohol. Conversely, a system Reid and Hofmanng find that “the solubility of kauri resin, comprising an ester of a strong acid and water should move as well as of any natural resin except shellac, may be im- correspondingly quickly towards equilibrium, since a t equiproved by subjecting the finely powdered resin t o atmos- librium the rates of esterification and hydrolysis must be pheric oxidation.” The failure of shellac to become more equal. Thus, the reaction of alcohol upon sulfuric acid is soluble on oxidation may be attributed to the presence origi- rapid. It is also reversible. I n fact, there is a process of nally of 26 per cent of oxygen in the principal acid of ~ h e l l a c . ~producing alcohol by adding water to ethyl hydrogen sulfate, As Brown6 has pointed out, there are many exceptions and distilling away the resulting alcohol. in the lacquer industry to the rule that like dissolves like. The above case is that of a very strong acid. Acids weaker Different oxygen-containing groups are not equivalent t o than sulfuric combine less rapidly with alcohols, yet there each other in increasing solvent power for pyroxylin or in- are processes of esterifying both lactic and oxalic acids with compatibility with resins. Yet the effect of increasing the ethyl alcohol, a t a commercially satisfactory rate, without percentage of hydrocarbon radical, in a given homologous the use of a catalyst. Acetic acid, on the other hand, is a series of solvents, usually is to decrease the solvent power weaker acid and is not esterified with ethyl alcohol, a t a for pyroxylin of high oxygen content and to increase the commercially satisfactory rate, without the aid of a catalyst. compatibility with resins of low oxygen content. More direct is the evidence of Palomaa.” I n studying the hydrolysis of esters of oxy-fatty acids, in alkaline soluR a t e of Hydrolysis tion, a t 15’ C., he finds that the velocity constants are apHydrolysis of a solvent, with the production of free acid proximately parallel to the dissociation constants of the or salts of metals present in enamels, is undesirable. At corresponding acids. least one solvent has caused livering of lacquer compositions Bibliography containing zinc oxide. It is important, therefore, to be able 1-Irvine, Denham, and Hirst, Chem. Trade J . , 71, 291 (1922). t o forecast what classes of esters may hydrolyze rapidly. 2-Hibbert, J. IND.ENG.CHEM.,13, 256, 334 (1921). Bridgmanlo has described methods of measuring the rate a-Brown, Ibid., 19, 969 (1927). of hydrolysis of esters. The writer has used a method that 4--Davidson, Ibid., 18, 670 (1926). 5-Dieterich (translation by Stocks), “Analysis of Resins,” Scott Greenmakes possible the listing of solvents in the order of rate wood & Son, 1920. of neutralization of an alkali. A solution which contains, 6-Brown, IND. ENQ. CHEM.,20, 183 (1928). per liter, 500 cc. ethyl alcohol, one equivalent weight of the 7-I,andolt-Bornstein, “Tabellen,” p. 1136, Julius Springer, 1920. ester to be tested, one-third equivalent of sodium hydroxide, 8-Williams, Gabriel, and Andrews, J . A m . Chem. Soc., 60, 1267 (1928). ENG. CHEM.,20, 497 (1928). and a few drops of phenolphthalein, in addition to water, 9-Reid and Hofmann, IND. is made a t room temperatures. The alkali is added quickly 10-Bridgman, Ibid., 20, 184 (1928). Ann. acad. sci. Fennicae, [A] 6, No. 4, 1 (1914); C. A . , 13, as the last ingredient of the mixture, and there is then noted 11-Palomaa, 2630 (1919). the length of time, after the addition of the last of the alkali, 12-Keyes, IND.EKG. CHEM.,17, 559 (1926). until the pink color of the phenolphthalein disappears. This 13-Formula chosen for abietic acid is that of Shaw and Sebrell, Ibid., 18, 612 (1926). indicates the time required for hydrolysis of a definite amount of the ester. With this method the data of the second column of Table V have been obtained.
+
+
+
Sulfoaluminates of Calcium
Table V-Rate ESTER Ethyl Ethyl Ethyl Ethyl
acetate lactate formate oxalate
of Hydrolysis of Esters TIME REQUIRED IONIZATION CONSTANT OF ACID’ FOR HYDROLYSIS WHOSERADICAL OCCURSIN ESTER Seconds 1200 1 . 8 X 10-6 105 1 3 . 8 X 10-5 1to 2 21.4 X 10-6 0 3800.0 X 10-5 (1st step)
It will be noted that the order of increasing rate of hydrolysis is the same as the order of increasing strength of the acid whose radical is contained in the ester. This relation is probably not a mere coincidence, although other factors,
Among the reaction products formed by the action of sulfate waters on Portland cement, there has been observed, under some conditions, a calcium sulfoaluminate, thought by some investigators to be responsible for certain expansion effects sometimes observed in concrete. The exact nature of this compound, its condition of formation, and stability have been studied by the Port!and Cement Association and the Department of Commerce. This compound is formed by the interaction of sulfates with lime and aluminates. It is relatively stable in water, but is decomposed by solutions of magnesium salts and of carbonates. A second calcium sulfoaluminate of lower sulfate content is relatively unstable and is consequently believed to have no significance in concrete.
