4th Annual
Review of Analytical CheMistry c
ONTINUING our review of developments i n analytical chemistry, the following nine articles report progress i n important fields of application. The fundamental developments were reviewed i n the January issue. A combined reprint of reviews from both issues is available at $1.50 per copy from the Reprint Department of the .AMERICAN
-The
CHEMICAL SOCIETY.
Editors
COATINGS T. G. ROCHOW AND R. W. STAFFORD American Cyanamid Co., Stamford, Conn.
T
H E analysis of coatings is the concern of this review. I t covers chemical and physical analytical methods applicable to organic high polymers and associated oils, waxes, pigments, and plasticizers, as disclosed in the literature during the past year. The scope of materials includes lacquers, varnishes, and paints, and also organic finishes for or on paper, textiles, leather, and metals. The treatment is abridged by arbitrarily excluding other important materials such as vitreous enamels, metals, and chemically treated metals, and by disregarding what are considered to be the less common uses. Following the arrangement of last year (66), general analytical schemes are considered first. T h e next section is devoted to the generally applicable resinography and related topics, the fundamental importance of which is evidenced by the increasing activity in this field. Monographs on the analysis of component parts of organic coatings are then considered in the order: separate classes of resins, oils and waxes, pigments and plasticizers, and specific constituents or functional groups. Auxiliary references to a limited bibliography on relevant descriptive or evaluative literature are presented as generally helpful background information. GENERAL ANALYTICAL SCHEMES FOR ORGANIC COATINGS
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A number of investigators have reported on general procedures which are directly or potentially applicable to the identification of high polymeric constituents of organic coatings. Nechamkin (48) classifies thirteen common types of plastics according to their behavior on fusion with metallic sodium. .4fter separation into sis groups, distinctions within each group are made by observing the solubility and the characteristics of burning. This simple procedure permits typing an unknown plastic. For the separation of high polymers by appropriate solvents, Thinius (66, 6 9 ) gives directions for the resolution of mixtures of cellulose ethers and esters, chlorinated rubbers, polystyrene, and polyisobutene into their components by selective extraction of the dry solids with various solvents and solvent mixtures. In a subsequent publication ( 6 8 ) , Thinius reports on the extension of this work t o include new data on nitrocellulose, on distinguishing polymers according to their tolerance toward diluents, and on distinguishing various degrees of substitution in saponified vinyl and cellulose esters. Di Xoia (ZO), in an attempt to separate
mixtures of natuial and synthetic resins with organic solvents, tabulates the physical and chemical properties of a number of iesins available in Argentina. He includes solubilities in common organic solvents and finds that fifteen such solvents, plus water, are sufficient to separate most polynler mixtures, prior to the application of a recommended systematized analytical attack. Castle (12) suggests dichloroacetic acid as a color reagent for natural and synthetic resins. Colomb (16) points out that the Liebermann-Storch-hlorawsky test for rosin can be applied to many other paint and varnish materials, including natural and synthetic resins, vegetable oils, and plasticizers. In a fairly recent P B report (32) 17 analytical methods for plastic materials, as used by I. G. Farbenindustrie, are listed. Polyvinyl compounds, plasticizers, urea compounds, and polychloroprene are covered. In the field of generally applicable analytical methods, Toeldte and Hezel (YO)critically discuss the determination of the saponification value by Hezel's method (29),which was cited in a previous review (66). Hahn (26) recommends potassium hydroxide dissolved in a 1 to 1 mixture of Cellosolve and xylene as an ideal reagent for the determination of saponification numbers. Shaefer and Balling (69) discuss the saponification of difficultly saponifiable esters, as eLemplified by rosin esters, using a diethylene glycol-phenetole solution of potassium hydroxide, and titrating the potassium salt formed by the Riemann double indicator method. Lenz (44) recommends the use of a 40-60 methanolbenzene misture in a Soxhlet-type apparatus to extract oil from pigment pastes. Thinius (6'7) suggests tetrahydrofurfuryl alcohol containing potassium hydroxide as a good agent for the determination of chlorine in aliphatic polymers. Smith and Shaw (63) have prepared a bibliography on resin analysis as a contribution from the Subcommittee on Resin Analysis of the Plastics Committee of the Technical Association of Pulp and Paper Industries. RESINOGRAPHY AND RELATED TOPICS
Bt the Annual Meeting of the Electron Microscope Society of America a t Franklin Institute in Philadelphia, November 8,9, and 10, 1951, several announcements were made which are of interest in the coatings field. E. B. Bradford of the Dow Chemical Co. studied electron microscopically the effects of plasticizers on the surface structure of films left by synthetic latices intended
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233
V O L U M E 2 4 , NO. 2, F E B R U A R Y 1 9 5 2 for the paint, paper, and textile industries ( 1 4 , 3 6 ) . He concluded that poor films result from lack of coalescence of the droplets of polymer. “ ~ ~ a s t i c i z e r s ”cause coalescence in various ways, depending on the polymer: with saran, b y reducing the surface tension of the droplets; with polystyrene, by serving asalubricant in facilitating closer packing of the droplets; with polyvinyl plastics, and in this case a n internal plasticizer, by the extension of the particulate surface area to wormlike shapes rather than spheres. The uniformity of dispersion of pigment n as also pictured in formulated latices. James Hillier of the Radio Corp. of America, using carefully corrected.electron objectives and taking precautions to minimize specimen contamination, focused exactly on particles of carbon black and showed surface reticulations less than 20 A . across ( 1 4 , 35). Virgil Peck and Wilbur Kaye of the Tennessee-Eastman Corp. etched and replicated the surfaces of cellulose acetate fibers and films (14, 35). They found that water in the plastic has a pronounced effect on the nature of the etched surface. They explained t h a t water may be insulating the chain molecules of polymer from one another. Electron microscopy increasingly facilitates differentiation and recognition among varieties and species of clays, pigments, and other particulate materials of interest in the coatings field. Max S ~ e r d l o wet a2. ( 3 6 ) , compare the electron microscopic morphology of kaolinite us. halloysite with the data obtained by differential thermal analysis and x-ray diffraction. B. M. Siege1 ( 3 5 ) studied homoionic montmorillonites. Kerr and a large team of coworkers have reported (4.2) to the American Petroleum Institute on the chemical, thermal, x-ray, light and electron microscopic, and infrared-absorption analyses of “known” samples of most of the commercially valuable species of clay and claylike materials. This is the most comprehensive description of clays yet assembled. .4mes and Sampson ( I ) publish results of a n electron microscopical study of the surfaces of films of nitrocellulose, unplasticized us. plasticized with castor oil or dibutyl phthalate. The film containing castor oil showed a granular surface composed of grains up to 0.1 micron in diameter, whrreas the film with dibutyl phthalate was as apparently homogeneous a t 20,000 X as the unplasticized film. Thus, the homogeneity, low permeability, and thermoplasticity of the dibutyl phthalate plastic can still be explained by the Doolittle (2OA) hypothesis that the dibutyl phthalate remains in the film as a nonvolatile solvent, preventing aggregation of the polymer molecules, reducing the formation of micelles, and resisting exudation on heating. The castor oil, however, exudes readily and leaves a permeable film of nitrocellulose. Apparently, the castor oil acts as a mechanical plasticizer- i.e., it separates the relatively small aggregates of polymer molecules. Richards ( 5 2 ) s h o w that, b y polymerizing ethylene under various conditions of temperature and pressure, a nide range of polymers is obtained, including oils, greases, soft and hard wases, and plastics both softer and harder than the familiar type of polymer used for electrical insulation and film. Some of these variations in properties are due to changes in molecular veights and their distribution; others are due to degree of chain branching (with commensurate degree of crystallinity). Some electron micrographic data are given, but the mriters understand from conversation with Richards that more electron microscopical information on polyethylene is forthcoming. Rochow, Botty, and Rowe ( 5 5 ) studied the drying of linseed oil electron microscopically. They found t h a t a film of lowviscosity, varnish-grade linseed oil, containing butyl catechol as inhibitor, contains particles around 20 A. in diameter, corresponding to a macromolecular weight of 2500 or less. Without inhibitor, the particle size of the oil film increases noticeably xithin 20 minutes of air-drying and within 1 week of drying, thr particle size reaches a magnitude of about 80 A. i n diameter or
about 160,000 in molecular w i g h t . By the addition of drier or by heat-bodying the oil before casting a film, intermediate particle sizes are obtained. In all the dried films, the particles show a t,endency toward zigzag alignment and felting of such strings. This may suggest the mechanism of film formation. Polyacrylonitrile in thin films shows a tendency of its fundamental particles to form stringers, and more strongly, to aggregate in rounded groups. Synthetic foils-Le., self-supporting films-are being studied microscopically. Vieweg and hloll ( 7 2 ) used light microscopy, particularly with the aid of phase contrast, to show the surface structures and to show the distribution of dyes and fillers, especially in plasticized polyvinyl chloride. Some insight into the internal structure of the polymer is gained by theuseof polarized light to observe the effect of a solvent on the double refraction of the foil. A hot stage permits the variation of temperatwe during such experiments. SPECIFIC CLASSES O F HIGH POLYMERIC MATERIALS
A considerable amount of interest has been shown in the problem presented by the analysis of styrenated alkyd resins and oils. Kappelmeier and his associates (37-39) report that data collected by chemical methods, particularly saponification values, on four Dutch commercial styrenated oils indicate that a large proportion of the fatty acids is linked to styrene and distributed over fractions possessing different properties. Separation of the various fract’ionsby selective solvents indicates that the styrenste oils in question contain little, if any, neutral polystyrene. The location and nature of the apparent linkage of styrene and/or polystyrene to the fatty acids still remain an open question. dokhout ( 5 ) describes a new analytical method for styrenated oils and alkyd resins, based on differential saponification n-ith alcoholic potassium hydroxide, and further states ( 7 ) that if a styrenated linseed oil is saponified iyith alcoholic potassium Iiydroside i n the presence of xylene, an aqueous solution of the dried reaction product yields a white precipitate on treatment with methanol. The precipitate is insoluble in water and is considered to be polystyrene. Bokhout’s conclusions have been criticized by Kappelmeier and van der Kcut ( 3 6 ) and the criticism has been answered by Bokhout ( 6 ) . Petit and Fournier ( 5 0 ) cluini that the mass polymerization of stywne, a-methylstyrene, benzoyl peroxide, and linseed (or tung) oil at 180” to 300” C. yielticd no copolymers, but only a mixture of polystyrene and oil. The oil reportedly contains a small proportion of an addition compound of one fatty acid chain ivith one styrene molecule. Bakes ( 2 ) reviews the chemical analysis of “styrolizedJJoils, Uischoff ( 4 )describes a method for the identification of modified arid unmodified phenol-formaldehyde resins which is based on the liberation of the phenol by fusion of the resin with potassium hydroxide followed by testing of the solution with p-nitroaniline diazonium salt. Chatfield ( I S ) discusses terl-butyl, oct,yl, and phenyl phenol varnish resins and briefly reviews fourteen test.* to be conducted. RIann ( 4 6 ) presents a detailed discussion of the application of infrared spectroscopy to the qualitative and quantitative estimation of polymers used in the rubber industry. Goldspiel arid Bernstein (244) describe the app1icat)ion of x-ray diffraction methods to the identification of natural and synthetic rubbers. Cianetti (15) detects chlorinated rubber in varnishes by the hydrogen chloride evolved from the pyrolyzed film and adds directions for quantitative separation. Haslani and Clasper ( 2 7 ) list methods for the analysis of Inistures of hesamethylenediamine and amino caproic acid isolated as the hydrochlorides in the acid hydrolysisof nylon-typepol>-tners. The latter is determined by titration to a phenolphthalein end point wit.h standard sodium hydroxide solution. To estimate the former, the mixture of chlorides is passed through a column of Aml)erlite IRA-400 and the hexamethylmediamine compound is titrated to a methyl orange end point with sodium hydmside
ANALYTICAL CHEMISTRY
234 solution. Zahn and IVolf ( 7 4 ) descrilie the analysis of polyamides and polyurethanes, giving details of the paper chromatogrnphy of the :iniino m c l dicarhosylic acid components. 111 discussing the anal>-sisofsilicon organic compounds, I i r a n d Bork ( 4 9 ) describe a chemical test, for the detection (if in technical products and list a series of color reactions to diffewntiate among alkyl and aryl chlorosilanes, alkyl and aryl alkoxysilanes, tetraalkyl silanes, and others. Rochon- and Rochow (54; 258, pp. 120-30) give some properties and molecular ncights of some silicone polymers. C o m e r and Eyler ( 1 7 ) give details of a method for the analysis of sodium carbosymethylcellulose. Schrenk (58), in discussing methods of test for nitrocellulose, includes methods for its detection and estimation in mixtures, as \vel1 as the determination of nitrogen content. Swann ( 6 6 )has developed a colorimetric method for the determination of rosin and rosin esters in paints and varnishes, which i5 a modification and extension of the Liebermann-Storch acetic anhydride-sulfuric acid test, and which employs a n electrophotomct,er. DeBaun and Nord ( 1 8 ) carry out the phloroglucinollignin color reaction in a spectrophotonieter cell and measure the optical density as a function of time. Data are given for lignins from a number of hard and soft woods. OILS AND WAXES
Iiawakami and Mil-ayoshi ( 4 1 ) present a discussion of the ultraviolet absorption spectra of a wide variety of fatty oils, and of the relationship between absorption spectrum, composition, and drying properties. Kewey and his colleagues ( 4 9 ) report on the segregation of fatty acids and their derivatives by extractive erystalli~at~ion with urea. When allowed to react with urea, the more saturated components form insoluble adducts. Sumeriea1 dat,a on the segregation of various fatty acids and derivatives are given. Kaufmann and associates (40) describe a spectroanalytical method for the determination of conjugated diene, t'riene, and tetraene fatty acids. Art'ificial mixtures of various proportions of 9,11-linoleic, eleostearic, and parinaric acids are analyzed as illustrative examples. Shreve and associates (62) have determined the infrared absorption spectra of nineteen pure long-chain saturated and mono-unsaturated fatty acids, methyl esters, triglycerides, and alcohols. The absorption bands are correlated with molecular structure. These investigators ( 6 1 ) have also used infrared spectrophotometry t'o determine the transoctadecanoic acids, esters, and alcohols in mixtures, and prove the accuracy and precision of the method by analyses of niriet,een synthetic mixtures of acids, esters, and alcohols of known composition. Cassidy and Sestler ( 1 1 ) discuss the principles and methods of applicat,ion of chromatography as used in the separation of fatty acids. The review covers the application of elution analysis, frontal analysis, displacement, analysis, and partit,ion chromatography. Boldingh (8) describes the quantitative separation of the saturated CG-CI8fatty acids bl- paper or column chromatography, using benzene absorbed in vulcanized rubber as the immobile solvent, and a strong polar solvent as the mobile phase. 4 s regards the fatt,y acids of lower molecular n-eight, Fairbairn and Harpur (22) give details of the chromatographic separation of the saturated C?-Csfatty acids from a single small sample, and Moyle and associates ( 4 7 ) describe the separation and estimation of similarly composed samples on buffered partition columns. Ivanovszky (33)presents a discussion of the various chemical and physical analyses of \vases, and their significance. H e proposes an analytical scheme comprising preliminary tests, such as ash, elementark analysis, etc.; physicochemical tests, such as acid and est,er values, melting-setting points, viscosity, etc. ; and technological and scientific examination, such as colloidal phenomena, mechanical properties, oil absorption, performance tests, etc. Sadtler ( 6 6 )reports on the infrared absorption spectrit of eighteen waxes.
PIGMENTS AND PLASTICIZERS C'a1~111:in :mcl llalherhe ( I O ) , in measuring the surface of paint pigrncnts and ot,lier fine powders, compare the gas permeability mc'thod Tvith those data obtained by one or several of the following: nitrogen absorption, liquid permeability, methyl stearate ahsorption, light and electron microscope, and sedimentation. Hunt, Wisherd, and Bonham (31) present the infrared spectra of 54 powdered minerals and pure inorganic compounds, and make a tabulation of the principal absorption bands. Included among the minerals arc many of interest to the paint industry. Haslan:, Soppet, and Killis (28) have prepared a thorough treatment of the probleni of analyzing plasticizers obtzfined from polyvinyl chloride compositions. A method of separation is described and a series of general and specific tests is listed. Directions for the separation of alcoholic components of estertype plasticizers, and of cresols from phosphate plasticizers are given, and include a seniimicro method and apparatus for the fornicbr. Identification is accomplished by a correlation of chemical and infrared spectroscopical methods. In a second section devoted to infrared spectroscopy, individual plasticizers are identified by comparison of their spectra with those of known standards. Reproductions of nineteen such are included, together with descriptions of the most characteristic bands for phthalates, phosphates, and long-chain aliphatics. llixtures are discussed in considerable detail. Use is made of the spectra of the separated acids and alcohols to resolve difficult cases. Semiquantit,ative results are obtained by coniparison with the spectra of mix.tures of known composition. This procedure is also applied to estimating relative proportions of mixed alcohols, as illustrated by a composite spectrum.
SPECIFIC CONSTITUENTS
This section includes separate constituents of coating materials. Haslani and Clasper ( 2 6 ) separate mixtures of adipic and sebacic acids by adding sufficient sodium hydroxide solution to neutralize the adipic acid alone, and then extracting with et,her in a continuous extractor. Shreve and Heether (60) propose an ultraviolet speetrophotonietric method for the determination of total phthalic anhydride in alkyd resins and other phthalate esters. After isolation of the phthalic acid as dipotassium phthalate nionoalcoholate, by the usual saponification procedure, the salt. is washed with water into a volunietric flask and the solution is acidified and made u p to volume. Comparison of the ultraviolet absorption spectrum of this solution ivith t h a t of a standard 1)ermits the quantitative estimation of the per cent phthalic anhydride in the original ester, The niet'hod is currently being studied cooperatively by Subcommittee SI of Committee D-1, ilmc>ricanSociety for Testing Xaterials. 1-askevich ( 7 1 ) converts phthalates to the dipotassium salt with potassium hydroxide, Trclat,ment with sulfuric acid converts the salt to the anhydride, which is then fused with resorcinol to yield fluorescein. Sanderniann ( 5 7 ) suggests a new color test for rosin acids, which, when combined with t,he Liebermann-Storch test and the determination of the maleic anhydride value, permits the rapid identification of commercial rosin products. Brown (9) describes the separation of fatty acids containing niore than one carboxyl group by paper chromatography. Stark, Goodban, and Owens (64)give directions for the chromatographic separation of a number of dicarhoxylic acids 011 ascending columns. IVurzschniitt (;3)used two new methods to analyze mixtures of monoethylene glycol, diethylene glycol, and diethylene glycol monoethyl ether: ( 1 ) RIonoethylene glycol alone reacts with alkaline copper sulfate to give a blue complex; the intensit'y of the color is used to estimate the quantity of the glycol, and the others are determined indirectly from the density; ( 2 ) diethylene glycol monoethyl ether is insoluble.in 72.570 potassium hydroxide solution. Jaffe and Pinchas (34) estimate dipentaerythritol in the presence of pentaerj-thritol by the infrared spectroscopy of the corresponding acetates in carbon tetrachloride. MacBeth
V O L U M E 2 4 , NO. 2, F E B R U A R Y 1 9 5 2 and Thompson ( 4 5 )present data for determining the composition of aqueous propylene glycol solutions by measuring the density at 35” C. and the refractive index a t 25’ C. Pohle and associates ( 5 1 ) submit the report of the Glycerol Analysis Committee. Collaborative work shows t h a t the sodium periodate method is more reproducible than the periodic acid method. The former is presented in detail. ‘Bennett (3),in reporting on qualitative tests for formaldehyde, reveals t h a t collaborative study indicates t h a t the HehnerFulton and the chromotropic acid methods are satisfactory. Details of the procedures are given. Duong (21) proposes the reaction with rn-phenylenediamine, followed by the addition of hydrochloric acid and oxidation with ferricyanide, asanewmethod for determining formaldehyde. Friedel ( 2 3 )records the infrared spectra of 22 phenols examined in carbon disulfide solution. Densham and Armstrong (19) describe the cell and the analytical procedure used in the analysis of alkyl phenols by infrared spectroscopy. Hossfeld (30) couples simple phenols with diazotized sulfanilic acid and chromatographically develops the sodium salts on carbonate-treated paper n-ith ethyl acetate-water. Results are given for a number of phenols. ACKNOWLEDGMENT
The authors &ish to acknowledge with appreciation the assistance of their colleague, James F. Shay, in keeping current the literature file on which this review is based. LITERATURE CITED
(1) Ames, J., and Sampson, -4. N. D., J . Applied Chem., 1, 337 (1951). (2) Baltes, J., Fette u. Seifen, 53, 160 (1951). (3) Bennett, H. P., J . Assoc. O&. Agr. Chemists, 33, 685-7 (1950). (4) Bischoff, Antonio, I n d . Bernice (Milan),4, 200 (1950). (5) Bokhout, B., Chem. Weekblad, 46, 836-7 (1950). (6) Ibid., 47, 159-60 (1951). (7) Bokhout, B., P a i n t Technol., 15, 344 (1950). (8) Boldingh, J., Rec. t m v . chim., 69, 247-61 (1950). (9) Brown, F., N a t w e , 167, 441 (1951). (10) Carman, P. C., and hlalherbe, P. le R., J . Applied Chem., 1, 105-8 (1951). (11) Cassidy, H. G., and Nestler, F. H. M., Discussions Faraday SOC.,1949,259-64. (12) Castle, R.. Chemistry and Industry, 1951, 129. Paint M a n u f . , 21, 9-13 (1951). (13) Chatficld, H. W., (14) Chem. Eng. News, 29, 4958 (1951). C&EN report on Electron Microscope Society of America, Annual Meeting. (15) Cianetti, E., Pitture e wernice, 4, 443 (1948). (16) Colomb, P., Lack-u. Farben-Chem., 3, 89-91, 107-110, 177-8 (1949); 4, 33-5 (1950). ANAL.CHEM.,22, 1129-32 (17) Conner. A. Z., and Eyler, R. W., (1950). (18) DeBaun. R. If.,and Nord, F. F., T a p p i , 34, 71-3 (1951). (19) Densham, A. B., and Armstrong, W.E., Chemistry and Indusf r y . 1950,776. (20) Di Noia, E. M., and Montes, A. L., Anales direc. nacl. q u h , 3, SO.5, 9-15 (1950). (204) Doolittle, 9. K., J. Polymer Sci., 2, 121 (1947). (21) Duong-Huu-Thoi, Govt. gen. afrique occidental franc., Compt. rend. premihre conf. intern. africanistes Ouest, 1, 102-3 (1950). (22) Fairbairn, D., and Harpur, R. P., Nature, 166, 789-90 (1950). (23) Friedel. R. -4., J . Am. Chem. Soc., 73, 2881-4 (1951). (24) Goldspiel, S., and Bernstein, F., A S T M B d l . , 171, 71-80 (1951). (25) Hahn, F. L., A n a l . Chim. Acta, 4, 577-9 (1950). (26) Haslam, J., and Clasper, M.,Analyst, 75, 688 (1950). (27) Ibid., 76, 33-40 (1951). (28) Haslam, J., Soppet, W., and Willis, H. A., J . Applied Chem. (London), 1, 112-24 (1951). (29) Hezel, E., Fabre u. Lacke, 56, 10-11 (1950). (30) Hossfeld, R. L., J . Am. Chem. S O C . , 73, 852-4 (1951). (31) Hunt, J. M., Wisherd, M. P., and Bonham, L. C., ANAL. CHEM.,22, 1478-97 (1950). (32) I. G. Farbenindustrie, Bibliography of Scientific and Industrial Reports, 9, No. 5, 393 (hpril 30, 1948); PB-L 70188. (33) Ivanovssky, Leo, Seifen-Ole-Fe?te-Wachse, 77, 213-19 (1951). (34) Jaffe, J. H., and Pinchas, Shraga. ANAL.CHEM.,23, 1164 (1951).
235 (35) J. Applied Phys., 23 (January 1952). Reprint of abstracts of papers presented a t ninth annual meeting of Electron Microscope Society of America, Franklin Institute, Philadelphia, Nov. 8 to 10, 1951. (36) Kappelmeier, 0. P. A4., and van der Neut, J. H., Chem. Weekblad, 47, 157-8 (1951). (37) Kappelmeier, C. P. A., van Goor, W.R., van der Neut, J. H., and Kist, G. H., Chim. peintures, 14, 92-101 (1951). (38) Kappelmeier, C. P , van Goor, W. R., van der Neut, J. H., and Kist, G. H., P a i n t , Oil Chem. Rev., 114, 16, 18-20, 32, 34-5 (1951). (39) Kappelmeier, C. P. A . , van Goor, W. R., van der Keut, J. H., and Kist, G. H., Verfkroniek, 23, 263-70 (1950). (40) Kaufmann, H. P., Baltes, J.,Volbert, F., and Brockhausen, K., Fetteu. Seifen, 52, 210-15 (1950). (41) Kawakami, K., and Miyayoshi, H., J . Agr. Chem. SOC.J a p a n , 17, 856-62 (1941). (42) Kerr, P. F., Research Project 49, “Reference Clay Minerals,” New York American Petroleum Institute, 1951. (43) Kreshkov, A. P., and Bork, V. A , , Zhur. A n a l . K h i m . , 6, 78-87 (1951). (44) Lens, H., Farbe u. Lack, 56, 538-9 (1950). (45) MacBeth, Gordon, and Thompson, Ralph, ANAL.CHEY.,23, 618-19 (1951). (46) Mann, J., J . Rubber Research, 18, 79-88, 89-97 (1949). (47) Moyle, Vivien, Baldwin, E., and Scarisbrick, R., Biochem. J., 43, 308-17 (1948). (48) Sechamkin, Howard, J . Chem. Education, 28, 97-8 (1951). (49) Newey, H. A , , Shokal, E. C., Mueller, A. C., Bradley, T. F., and Fetterly, L. C., I n d . Eng. Chem., 42, 2538-41 (1950). (50) PeCit, J., and Fournier, P., Peintures, pigments. vernis, 26, 357-9 (1950). (51) Pohle, W. D. et al., J . Am. Oil Chemists’ Soc., 27, 412-13 (1950). (52) Richards, R. B., J . Applied Chem., 1,370-6 (1951). (53) Rochow, T. G., Botty, M. C., and Rowe, F. G., Abstracts of Papers, p. 275, XIIth International Congress of Pure and Applied Chemistry, Yew York, 1951. (54) Rochow, E. G., and Rochow, T. G., J . Phys. and Colloid Chem., 55, 9-16 (1951). (55) Rochow, T. G., and Stafford, R. W., ANAL.CHEY.,23, 312-16 (1951). (56) Sadtler, Philip, Proc. ChPm. Specialties Xfm. Assoc., 1950, 1903 (December 1950). (57) Sandermann, W., Farbe 7 ~ Luck, . 56, 339-40 (1950). (58) Schrenk. E., Bull. Schweiz. Verein, Lack-u. Farben-Chem. u. Tach., 1950, NO. 7, 49-59. (59) Shaefer, W. E., and Balling, TT. J.,- 4 ~ aCHEM., ~. 23, 1126-8 (1951). (60) Shreve, 0. D., and Heether, M. R., Ibid., 23, 441-5 (1951). (61) Shreve, 0. D., Heether, hl. R.. Knight, H. B., and Swern, Daniel, Ibid., 22, 1261-4 (1950). (62) Ibid., pp. 1498-1501. (63) Smith, E. V., and Shaw, T. P. G., T a p p i , 34, No. 5, 123A&84 (1951). (64) Stark, .J: B., Goodban, 9. E., and Owens, H. S., A N ~ LCHEM., . 23,413-16 (1951). (65) Swann, hl. H., Ibid., 23, 885-8 (1951). (66) Thinius, Kurt, Chem. Tech. (Berlin), 2, 321-30 (1950). (67) Ibid., 3, 59-62 (1951). (68) Thinius, Kurt, Deut. Farben-Z., 5, 73-81 (1951). (69) Thinius, Kurt, Farben. Lacke, Anstrichstoffe, 4, 381 -5 (1950). (70) Toeldte, W., and Hesel, E., Farbe u. Lack, 56, 149-50 (1950). (71) Vaskevich, D. N., Zhur. A n a l . K h i m . , 5 , 354-7 (1950). (72) Vieweg. R., and Moll, J., Kunststoffe, 40, 317-21 (1950). (73) Wursschmitt, Bernhard, 2. anal. Chem., 133, 12-17 (1951). (74) Zahn, H., and TTolf. H.. Melliand Textilber., 32, 317-21 (1951). AUXILIARY BIBLIOGRAPHY
(75) .kiken, J. K., and Jones, H., J . Oil Colo?ur Chemists’ Assoc., 30, 150-72 (1949). Sebacic acid polyesters in surface coatings. Discussion of differences between sebacic acid and phthalic acid polyesters. (76) ANAL.CHEM.,23, 2-101 (1951). Third annual review of analg tical chemistry. (77) Bachman, G. B., Filar, L. J., Finholt, R. IT7., Heisey, L. V., Hellman, H. M., Lewis, L. L., and hficucci, D. D., I n d . Eng. Chem., 43, 997-1002 (1951). Properties of new synthetic rubbers and plastics. New synthetic elastomers have been prepared and physical properties studied. (78) Bailey, A. E., “Industrial Oil and Fat Products,” 2nd ed., Xew York, Interscience Publishers, 1951. (79) Barnett, C. E., and Jones, H. C., I n d i a Rubber World, 123, 4550 (1950). Optical properties of pigments employed in rubber. Effects of impurities on properties of pigments are emphasized.
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ANALYTICAL CHEMISTRY
(80) Batser, H., Makromol. Chem., 5 , 5-82 (1950). Linearpolyesters.
Relationship between viscosity and molecular weight depends on structure and size of macromolecules, their interaction with solvents. and tcmperature. (81) Berl, W. G., editor, “Physical Methods in Chemical Analysis,” T’ol. 11, Xew Toi,k, Academic Press, 1951. ( 8 2 ) Bevan, E. .I..Paint Trchnol., 15, 485-8 (1950). Styrene copolymers. Theories are suggested concerning the chemical natures of styrenated oil and styrenated alkyd reaction products. (83) Elout, E. R.. and l l a r k , H., “Monomers,” Xew York. Interscience Publishers, 1951. (84) Bradley, T. F., Paint I n d . Mag., 6 6 , KO.3, 8-10, 12-15 (1951). Some new developments in drying oil and varnish tpchnology. 1950 Josesh J. SIattiello lecture. (85) Bragdon, C . R., and Renfrew, 11. XI., Ind. Eng. CAem.. 43, 1272-82 (1951). Paint, varnish, and plastics chemistry. History of this branch of chemistry and of its section within .?ICs. (86) Rnchanan. G. R.. Pain2 I d . itfag,, 6 5 , 150, 151-2. 153-4. 155, 157 (1950). Plasticizers, properties, and uses i n film-forming materials. (87) Buttrey, D . S.. “Plasti~izers,”London, Cleaver-Hume Press, 1950. (88) Craig, F. A sProc. Trcii. Sect., Brit.Paper and Board M a k e r s Assoc.. 31, 81-99 (1950). Dyes and their application to paper. Discussion of selection, use, and identification of dyes and pigments foi, beater addition. (89) Eyssen, G. R., Paint Oil Colour J . , 120, 30-2, 34, 36 119.51). Ultrasonics. application to plastics and paint industries. (90) Falkner, D., Bjit. Plastics, 23, 183-9 (1950). Recent developnicnts in plasticization, 69 references. (91) Feigl, F., Research ( l o n d o r i ) , 3, 550-7 (1950). Chemistry of e. and sensitive reactions. A review. (92) Fettes. E. 31..and Jorczak, J. S., I i i d . Eng. C h m . , 42, 2217-23 (1950). Polysulfide polymers. Rcview of current crude rubbers, latices. and liquid polymers with emphasis on possible variations. .~ (93) Fleck. H . R.. “Plastics, Scientific and Tcchnological,” 3rd ed., London, Tcmple Press, 1951. (94) Frith. E. SI.. and ‘ h r k e t t . R. F., “Linear Polymers.” London, Longmans. Green 8r Co.. 1951. (95) Goehel, C . G.. and Sloore. D. T.. Pai~itVarnish Production X g r . , 41, So. 8 , 2 0 , 38 (1951). Dimer acid in surface coatings. Chemistry of I)reparatioti i 3 reviewed and uses are disrussed. (96) Goldenhill, Robert, Uro. Fiuishing, 12, S o . G. I G - l S (1951). Amino resins in orgauic finishes. Review of preparation, properties, and applications of amino resins. (97) Hahn, F. J., Am. Paint J., 35, No. 39, 58, 60, 62-3, 66, 68, 70, 72 (1951). Postplasticized polystyrene emulsion in water paints. Some formulations for polystyrene and styrene copolymer emulsions in water paints are tabulated. (98) Hall, C., Plastics Inst. (London), Trans., 18, 38-45 (1950). Cellulose finishes. A review. (99) Hanau. W. J.. Paint Varnish Prodwtion M g r . , 31, S o . 2, 17-19, No. 5, 25-6, 41 11951). Vinyls for surface coatings preparation and structure are reviewed, and properties and applications as they apply to coatings are discussed. (100) Hauser, E. A., P S A Journal, 17B, 46-7 (1951). Photomicrography by incident light in organic high polymer research. (101) Hilditch, T. P., Paint Ind. Mag., 66, S o . 4, 13-16 (1961). Drying oils. Emphasis is placed on changes taking place during early stages of transformation of drying oils. (102) Hine, D. J., and John, Y. B., J . Rubber Research, 19, 107-12 (1950). hlicroscopic and electron microscopic examination of rubber compounding ingredients. General survey. Literature on use of ordinary microscope, ultramicroscope, ultraviolet and electron microscopes in studying nature of latex. structure of unvulcanized and vulcanized rubber, and compounding ingredients and their dispersioninrubber is reviewed. (103) Hochtlen, A . , Kunstefofle, 40, 221-32 (1950). Polyurethane resins. Comprehensive survey of chemistry, properties, and uses. (104) Johnson, F. D., Can. Paint & Varnish Mag., 24,22,24,26,36-8 (1950). New coating resins. Brief description of polymet.izable polyesters, styrene-butadiene copolymer, polyethylene. polytetrafluoroethylene, and polyvinyl acetate and polystyrene emulsions. (105) .Johnson, W. C., “Organic Reagents and Organic Analysis.” Chadwell Heath, Fssex. Hopkin and TTilliams, 1950. (106) ,Jones, H.. Hill, h.,and TT’illiamson, I., Plastic Inst. (London), Trans.. 18, No. 33, 50-68 (1950). Plasticizers for polyvinyl rhloride. hmount of plasticizer required to produce standard modification of property of pure polymer is determined for 21 plasticizers in polyvinyI rhloride. ~
(107) Kapur, S. L., Paint ik’anuf., 21. 5-8, 13 (1951). Crystallization in high polymers. Discussion of main structural differences between polymeric and ordinary materials. 1108) Kline, G. M., Ind. Chemist, 42, 2001-6 (1950). Plastics. Review with 124 recent references. (109) Kline, G. M., “1960 Modern Plastics Encyclopedia and Engineer’s Handbook,” Kern. York, Charles A. Breskin, 1950. (110) Kroner, A. .I.,Soap, Sam?. Chemicals, 27, No. 3, 110-13, 133 (1951). T h a t replacements for carnauba wax? Physical and chemical constants of 38 waxes. (111) Kunin, Robert, and Myers, R. J . , “Ion Exchange Resins.” New York, John Wiley & Sons, 1950. ! I 12) Lawall, 1%’. hl., Sational Paint, T’arnish Lacquer Assoc., Sei. Sect., Circ. 743, 211-388 11950). U. S. Government paint specifications. (113) Levitt, B., “Oil, Fat, and Soap.” Sew York. Chemical Pnblishing Co., 1951. 1114) McCann, Hiram, editor, “Modern Plastics Encyclopedia and Engineers’ Handbook,” 1951 ed.. New York, Plastics Catalogue Corp.. 1951. (115) Marron, T. U., and Chambers, ‘T,9..h . 4 ~ CHEXL, . 23, 548-50 (19,51). Infrared spectrometry in graphic arts. .Ipplication to specification, purification, and manufacturing control of petroleum oils, plasticizers, natural waxes, inks, etc. 1116) Marsel, C. J., Chem. Inds., 6 7 , 563-9 (1950). Waxes, types, production, properties, and uses. Review with 15 references and list of waxes on the market,. (117) Martin, 3. H., Paint Manuf., 20, 405-8 (1950). Pigment particle size. Methods for measuring particle size and surface area of pigments are briefly reviewed. (118) Jfellon, M. G., editor, “Analytical Absorption Spectroscopy, Absorptimetry and Colorimetry,” New York. John Wiley & Sons, 1950. (1 19) Melville, H . IT., and Murray, A . J. R., Trans. Faraday Soc., 46, 996-1009 (1950). Ultrasonic degradation of polymers. Theoretical. (120) RIeyer, K. H., “Xatnral and Synthetic High Polymers,” New York, Interscience Publishers, 1950. (121) Mills, TV. G. B., Paint, Oil, Colour J . , 119, 36-8, 40, 42 (1951). Technical progress in 1950. Review covering pigments, drying oils, driers, varnishes, resins. plant and equipment, corrosion, fouling, and weathering. (122) Morgans, TT. XI., Paint manu,^".. 20, 387-90, 400 (1950). Review of pigment progress. Covers white and colored pigments, carbon blacks, pigment dyes, metallic powders, fluorescent and phosphorescent pigments and mineral extenders. 1123) Morrison, G. H., ANAL.CHEM..22, 1388-93 (1950). Role of extraction in analytical chemistry. Review of analytical liquid-liquid extractions, including apparatus and general techniques. ,124) Muller, R. H., and Clegg, D. L., Ibid., 23, 396-403 (1951). Paper chromatography. Instruments and techniques. (125) Namaro, R. T., Am. Printer, 131, 34-5 (1950). Plastic-coated papers. Application of vinyl plastics, nitrocellulose, ethyl cellulose, rosin, and polyester resins to paper. 1126) Penn, IT’,S., Plastics (London). 15, 18-21 (1950). Pyrolysis of polymers. Review with 25 references. ! 127) Phys. Methods in C h ~ u i -. 4 ? l c f ~2, . , 2-49 (1951). STetallurgical polarographic analysis; polarimetric titrations. Review and discussion with rnanyreferences. < 128) Piskur, M. A I . , J . Am. Oil Chemists’ Soc., 28, 198-215, 246-Gi (1951). Annual review of literature on fats, oils, and soaps. i 129) Platzer, Norbert, Modern Plastics, 28, No. 7, 95-6, 98, 161-2. 165-6 (1951). Polyvinyl alcohol. Review with 98 references. 7 : j O ) Powell, 0 . A I . , Ani. Paint ,J., 35, S o . 46, 32, 34,36, 38, 40, Xu. 47, 62, 64, 66, 68, 70, 72 (1951). Vinyl resins and coating industry. Discussion of vinyl coating solutions and dispersions. (131) Powers, P. 0.. Ind. Eng. C h e n ~ . 42, . 2096-9 (1950). Styrcnation of fatty acids. Description and interpretation of empirical data. 1132) Ratti, H. J., India Rubber World, 123, 451-4 (1951). Vinyl plasticizers. Review and discussion, including classification of stabilizers, their characteristics, and testing methods. 1133) Redlich, O., Gable, C. RI., Dunlop, A, K., and Millar, R. \I-., J . Am. Chem. Soc., 72,4153-60 (1950). Addition conlpounds of urea and organic substances, Methods for determining composition of solid urea complexes and for measuring equilibrium constants of decomposition. (134) Reed, M. C., India Rubber World, 123, 322-3 (1950). Plasticizers for vinyl films and sheeting. Review and discussion of various problems, and behavior of different types of plasticizers. (135) Richardson, H . M., Mech. Eng.. 73, 211-15 (1951). Plastics
. V O L U M E 2 4 , NO. 2, F E B R U A R Y 1 9 5 2
(136) (137) (13s) (139) (140)
(1411 (142) (143) (144)
(145) (146) (147)
(148)
237
literature references. selected for mechanical engineers, July 1949 through June 1950. 139 references are classified. Rinse, J., and Korf, C.. J . Oil and Colour Chemists’ 24ssoc., 32, 593-8 (1949). Styrenated oils. Various theories of mechanismof dryingoil-styrene reaction are explained and criticized, Robinson. R. S., Ibid., 33, 353-68 (1950). Modification of alkyd resins. Discussion of possible modifiers and their effect o n resin properties. Itorhow, E. G., “Introduction to the Chemistry of the Silicones,” 2nd ed., New I-ork. John Wiles & Sons, 1951. Iloycr, G. L., d 7 n . D u s f u f Reptr., 39, Proc. hm. dssoc. Textile Chemists Colorists, 8T7-87 (1 950). Review of textile roloring and finishing research. Salonion, G., van Amerongen, G . J., ran Veersen, G . J . , Schuur, G., and deDecker, H. C. J., I n d . Eng. Chem. 43,31519 (1951). Plastics from natural ruhher. Review and discussion of present developments. Sandell, E. B.. “Organic Reagents for Organic =inalysis,” 2nd ed., S e w York, Chemical Publishing Co., 1950. Sch:ich, William, editor. “A Manual of Plastics and Resins.” New York, Chemical Publishing Co., 1950. Schlenk, €I., and Holman, R. T.. Science, 112, 19-20 (1950). Urea complexes of unsaturated fat acids. General behavior and use in fractionation. Siggia, Sidney, - 4 ~ 4CHEX. ~ . 23, 667-8 (1951). Quantitative functional group determination in identification of organic compounds. Ratio of functional groups and the functional equivalent weights are used to identify organic compounds Sirota, J., Org. Finishing. 11, 11-15 (1950). Dispersion coatings. Diluents, plasticizers. stabilizers, pigments, and coating equipment are discussed in detail. Yniethui,st. J., and Cam. IT., Paint Mnnuf., 20, 391-6, 408 (1950). Progress in pigment, dyes, Review covering presentday trends. Smith, J. IT., Science Progrr,ss, 38, 698-706 (1950). Recent advances in science: gelleral and physical chemistry. Review of recent researches on clathrate addition compounds of quinol. and somewhat similar “adducts” of C-chain compounds with urea. Stocker, E., Bull. Schweia. Verein. Lack u . Farben-Chem. u . Tech., 1950, No. 7, 2-21, Review of chemistry of pigment
dyestuffs. Structural formulas and properties of pigment dyestuffs are listed. (149) Taylor, C. J. A , Brit. Catalogue of Plastics, 77-86 (1950). Synthetic resins in surface coatings. Surface coatings are reviewed under headings “nonconvertible” and “convertible.” (150) Technical Staff, Shell Chemical Corp., Paint, Oil Chem. Reo., 113, No. 23, 15-18, ‘48-9 (1950). Epon resins, new film formers. Discussion of chemistry and applications, including physical properties and suggested formulations. (151) Tuckett, R. F., “Linear Polymers,” New York, Longmans, Green & Co., 1951. (152) Ullrich, R. C., and Boddorff, R. E . , Oficial Digest Federation Paint Varnish Production Clubs, No. 312, 6-27 (1951). Lacquers, for paper, detailed discussion. (153) Vale, C. P., “Aminoplastics,” Xew York, Interscience Publishws, 1950. 1154) Wada, Y.,Shimbo. S., and Oda, M., J . P h y s . Soc. J a p a n , 5, 345-8 (1950). Dispersion of ultrasonic velocity in liquid fatty acids. It is suggested that characteristic “resonant frequency” may be used in qualitative analysis of fatty acids. (155) Warsdall, H. C., Paint Technol., 16, No. 183, 99-102, No. 184, 147-52 (1951). Rubber derivatives in paints and printing inks. History, chemistry, and uses of chlorinated rubber, oxidized rubber, and isomerized or cyclized rubher are reviewed. (156) Weigan. F. G., Am. Paint J . , 35, 62-3, 66 (1950). Silicone polymers and their application in protective coatings. (157) Williams, G. C.. Oficial Digest Federation Paint and Varnish Production Clubs, No. 311, 1020-32; Am. P a i n t J . , 35, No. 8-B, 26-7, 28-9, 30 (1950). Chemical composition and adsorptive properties of clear films. Subjects discussed include ultimate analvsis of clear films. extraction of clear films to determine solucle phase, and adsorptive properties of films for organic liquids. (158) lyrigley,A. N., siciliano, J ~&fast, ~1 ~ c., .~ and Fischer, ~ , C, H., U. 5.Dept. Agr., Bur. Agr. Ind. Chem., AIC-266, 7 (1950). Preparation and properties of styrenated allyl starch. RECEIVED December 21, 1951.
FOOD JOHN R. MATCHETT A \ D HARRY W. VON LOESECKE Bureau of Agriculturul and Industrial Chemistry, United States Department of Agriculture, Washington, D. C . I
T
HE present review rovers the period of about Decenher
1950 to hTovember 1951. It, is a sequel t o the review of nietliods of food aixtlysis for the period December 1919 to S o v ember 1950 (124). MOISTURE
Improved methods of determining moisture in a variety of food product,s are still sought. Several papers in t,his field appeared in a sj-mposium for moisture tiet,erniination (58, 127, 182, 186) and one paper from France has made a critical review of numerous methods, giving particular attention t o t h e procedure of Karl Fischer (80). Earlier work by Shan. et al. (f59),reported in a previous review (124), showed t h a t magnetic almorption b y protons may be used t o measure water content in t h e range encountered in natural and dehydrated biological materials, energy absorption varying linearly w-ith t h e amount of water in t h e t,issue. A more recent paper by these workers (160) discusses new measurements of proton magnetic resonance for a number of hygroscopic substances containing u p t o atlout 20% water. .i new approach t o the determination of water in fruits and vegetahlrs has heen proposed ( f O i ) , t h e organic content of the sample being measured by t h e quantity of pot,assium dichromate required t,o oxidize it. K a t e r content is then determined by differerlce.
Replacement of d r y methanol in t h e Karl Fischer reagent, by formamide has been suggested in the det,erminat,ionof moisture in dehydrated vegetables (114). A discussion of relative merit’s of t h e Karl Fischer method and other methods of estimating wat,er in molasses will b e of interest t o sugar chemists (46). A rapid method of determining water in fruit purees and concentrates involves employing a suitable desiccant to absorb the water from t h e sample (143). T h e increase in weight of t h e absorbent, corrected b y a blank, represents the moisture content of t h e sample. Rapid methods have also been suggested for moisture determinations in sausage products (66)and in grains (9), t h e latter being based on the determination of the dielectric const,aiit of t h e whole grain, which can be obtained in a few seeonds and translated to moisture content with an acruracy of +0.270. Package designers for protection of food during storage will be interested in t h e graphical interpolation method for measuring equili1)rium relat,ive humidity (103). T h e basis of the method is that. a material does not change in weight when exposed t o an atmosphere of equilibrium relative humidit,\. This condit,ion is determined b y graphical interpolation from d a t a on rate of change of weight a t different humidities. T h e n:ethod is applicable t o a wide variety of foods and is simple, inexpensive, and rapid, I n this connection, a recently published method for measuring t h e rate of transmission of organic vapor through
