Jan., 1913
T H E JOURA’AL OF I N D C S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
found t h a t treatment of such a “dead” film with hydrazine hydrate was sufficient t o regenerate its powers of development. The same result was obtained with a film after immersion in warm, dilute hydrogen peroxide-no development occurred until the layer of oxide so produced had been reduced with hydrazine. THEORY AND CONCLUSIONS
Schiitzenberger, b y the electrolysis of copper acetate solutions, obtained a t the cathode a peculiar form of copper; and, being unable t o explain its unusual behavior, he announced it a s a n allotropic modification. Wiedemann incorrectly contended t h a t the new form of copper was really the oxide of t h a t metal, while recently Benedicks has advanced the idea t h a t we have t o deal with a solid solution of acetic acid in copper. It can be shown, however, b y a careful study of their results by, and consideration of, the facts of colloid chemistry, t h a t the allotropic copper of Schutzenberger is merely the normal metal in the form of a n irreversible colloid gel. The same conclusion is applicable to the deposits of gelatine-copper described in this paper. The gelatine acts here a s the “protecting colloid,” migrates b y cataphoresis t o the cathode, and there inhibits the growth or crystallization of the copper nuclei. Gelatine-copper is a n irreversible gel of colloidal copper. The whole phenomenon is b u t another example of the marked influence of organic and other colloidal substances upon metals prepared b y electrolysis, accounts of which have appeared in the recent papers of Muller and Bahntje, Snowdon and others. What is the nature and mechanism of the process of the color development? This is indeed a difficult problem, chiefly because of the exceeding small quantities of reacting material of necessity dealt with. The blue, although a superficial color, is nevertheless not the color of a thin film of gelatine or oxide bringing about interference disturbances in the reflected rays of light. Nor does i t seem t o be the color of a definite chemical compound. The blue layer does contain oxide as is shown b y its action with hydrazine and yet i t cannot be prepared b y any process of simple oxidation. It cannot be produced by the partial coagulation of the copper gel. It was shown b y Wiedemann t h a t Schutzenberger’s copper possesses the power of adsorbing very considerable quantities of copper oxide from copper acetate solutions. This observation furnished the clue t o the process of development. The color changes t h a t appear upon the film are the result of a surface adsorption of h y d r o u s copper oxide from the copper solzttion. The hydrous copper oxide is present as a suspension in very appreciable quantities in the acetate or propionate solutions, being the product of hydrolytic dissociation. This being the case, we should expect the best development with the acetate solutions and but little color effect with the sulfate and chloride developers. The reversal of development caused by hydrazine is due to the reduction of the adsorbed oxide. There seems to be a certain definite concentration of oxide
I1
in the copper film necessary for the production of a blue color. As the concentration of the oxide increases by continued adsorption, the film passes through the series of colors so distinctive of the development. I n conclusion it can be said in support of this hypothesis t h a t it is in accord with many of the established facts in colloid chemistry and explains in the best possible manner this decidedly obscure phenomenon. Stannic oxide adsorbs gold from suspension and forms the “Purple of Cassius;” under very special conditions colloidal copper adsorbs hydrous copper oxide and similarly gives a n intensely colored adsorption compound. SUM M . 4R Y
The electrolytic production of a form of colloidal copper was performed with certain copper solutions containing gelatine. This new form of copper develops a remarkable series of colors when immersed in certain copper solutions, a peacock-blue being the finest color obtained. The process of development is a n adsorption of hydrous copper oxide by the surface of the colloid film. There have been described methods of coloring metal objects gold, golden brown or red. CORNELL UNIVERSITY ITHACA.NEW YORK
THE CLASSIFICATION OF BITUMINOUS AND RESINOUS SUBSTANCES’ By HERBERTABRAHAM
The terms bitumen, asphalt, resin, tar, pitch, etc., are in common use, yet i t is surprising to note how inadequately they are defined in most of the standard works and text-books. This may be explained b y the fact t h a t these words originally had limited meanings, but in keeping pace with the progress of science they were extended in scope until they completely outgrew their original bounds. I t is probable t h a t each of the expressions a t first pertained t o the aggregate properties characteristic of some typical substance closely associated with the processes of daily life. Thus, the generic term “resin” originated in the word “rosin,” and it even now alludes t o substances resembling ordinary rosin in appearance and physical properties. Similarly our comprehension of the generic term “wax” is based largely on the physical characteristics of the oldest known wax; namely, common beeswax. From time to time, as new substances were discovered in nature, or produced in the arts, the meanings of these words were arbitrarily extended t o include them. This resulted in a certain amount of overlapping and consequent confusion. AS the chemistry of these substances was investigated, this was in certain cases adopted as a n additional means of differentiation. But we are still forced t o rely principally upon the physical characteristics of these groups of materials, for even to-day comparatively little accurate information is available with respect t o their chemical composition. I t is probable, however, 1 Paper presented a t the Eighth International Congress of Applied Chemistry, New York, September, 1912.
I2
T H E JOURNAL OF I N D U S T R I A L AND E,VGINEERING CHEiWISTRY
that in the future this latter will be adopted as a basis of nomenclature. The complexity of these terms and the existing confusion becomes especially apparent in attempting to define and limit the scope of claims in letters patent. We are not infrequently confronted with this problem in patent controversies, owing to the relatively large number of patents classified under the heading of “Plastic Compositions,” and involving the use of asphalts, pitches and the like. The object of this paper is to submit a list of definitions and a system of classification gradually evolved by the author while engaged in “patent causes.” I n this connection, i t might be stated t h a t several of these definitions (e. g., resin, bitumen, resinous substance and bituminous substance) have already been accepted by the courts in this country. The author hopes, therefore, that a t least some of his findings may be of value to the committee now engaged in fixing the nomenclature of bitumens. The definitions which will follow have been based on one or more of the following items:
Jan., 1913
occurring2 hydrocarbon complex, 7 insoluble in water, 1 1 but completely soluble in carbon disulfide, benzol. etc.I3 Asphalt(um).-A dark colored,23 and more or less viscous t o solid17 hydrocarbon complex,7 including: ( a ) The easily fusible bitumens33 often associated with a mineral matrix,s not having a “waxy” lustre27 or unctuous fee1.30 (b) Fusible residuums obtained from the distillation,3 oxidation,4 sulfurization,s etc., of bitumens. A4sphaltite.-A dark colored,23 s0lid,3~ difficultly fusible,34 naturally occurring2 hydrocarbon complex,7 insoluble in water,rl but more or less completely soluble in carbon disulfide, benzol, etc.13 True Resin.-A term applied to various vegetable principles occurring in, or obtained from, the secretions or saps of certain plants and trees.1 They are hard, fusible33 and more or less brittle, non-adherent to slightly adherent29 solids a t ordinary temperatures,QO usually light colored in mass,”1 having an amorphous structure,Zj conchoidal fracture26 and “resinous” lustre.28 They are insoluble ,in water,” but more or less completely soluble in carbon disulfide, benzol, I . Origin. etc.13 They are oxidation or polymerization products I . Natural 2 . Artificial-Obtained from of the terpenes, and generally contain “resin” acids Mineral Distillation processes and esters. Vegetable Oxidation processes Animal Sulfurization processes Resinous Substance.-A term applied t o ( a ) sub3. Variable. stances containing true resins. ( b ) Substances of 11. Composition. variable origin6 and composition’” resembling true I n such cases where this is known with certainty. resins in their physical properties (with the exception 111. Solubility. of color), and solubility (vide true resins). I n water Mineral Resin’.-A term applied to the solid bituI n carbon disulfide, benzol, etc mens (vide bitumen). IV. Physical Properties. Oleo Resin.-The viscous t o semi-solid16 and usually I. Hardness 5 . Lustre light colored solutions of true resins in essential oils,9 Liquid Waxy either obtained from, or constituting, the saps of Viscous Resinous. certain plants and trees. Semi-solid 6. Feel: Solid. Gum Resin.-The semi-solid19 to solid and usually Adherent 2. Color in Mass Non-adherent light colored22 emulsion or mixtures of true resins with Light Unctuous. various gums (carbohydrates), constituting the sap Dark. 7 . Odor: of certain plants and trees, partly soluble in water.“ 3. Structure Tarry, etc. Tar.-A dark ~ o l o r e d , ~ bituminous 3 substance, Amorphous. 8. Behavior towards Heat: 4. Fracture liquid or semi-liquid a t room temperature, often posFusible Difficultly fusible Conchoidal sessing a characteristic “tarry” odor,3‘ usually insoluble Infusible. Hackly. in water,II but miscible with carbon disulfide, benzol, DEFINITIONS etc.,13 and which on distillation, oxidation, etc., forms Bitumen.-A naturally occurring2 hydrocarbon com- a pitch. I t s composition’” and origin6 are variable. Pitch.-A dark c0lored,~3fusible33 and more or less plex,: often associated with a mineral matrix,8insoluble in water,“ but largely soluble in carbon disulfide, viscous t o solid17 bituminous or resinous substance, benzol, etc.13 Its color24 and hardness”1 are variable. insoluble in water11 but more or less completely soluble Pyro Bitumen.-A dark c o l ~ r e d , solid,24 ~s infusible,sj in carbon disulfide, benzol, etc.13 I t s compositionro naturally. occurring2 hydrocarbon complex,7 often and origin6 are variable. Wax-.-A term applied t o U ~ C ~ U O U S fusible33 , ~ ~ associated with a mineral matrix,8insoluble in water,’I a n d relatively insoluble in carbon disulfide, benzol, and more or less viscous to solid17 substances, having a characteristic “waxy” lustre,z‘ and which are inetc.I4 Bituminous Substance.-A term applied to ( a ) soluble in water,II but more or less soluble in carbon substances containing bitumens or pyro bitumens. disulfide, benzol, etc.I3 They are extremely suscepti(b)LSubstances resembling either the viscous or solid17 ble t o changes in temperature.3” Their composition,ro . bitumens, or pyro bitumens14 in their solubility and origin6 and color24 are variable. The terms “resinous substances” and “bituminous physical prowrties, i. e., having a n amorphous strucsubstances” overlap, as i t were, for both of them ture’s and dark color in mass.23 Malthk-A dark coloreds3 and viscous,’j naturally include mineral waxes, asphaltum and asphaltites
T H E J O U R A Y A L OF I S D U S T R I A 4 L A-YD EA\-GI.\‘EERI.YG
Jan., 1913 This
is
made
RELATIOK ORIGIN
clear
1
following
table:
[ Natural
Bitumens
Gas Petroleum 4 Mineral Wax+ +Mineral Wax 1 Asphaltum C +Asphaltum !Asphaltites f +Asphaltites
Pyro Bitumens
’
1
i
i
F;l:ite Bituminous Coal Anthracite Coal Metamorphosed Asphalts
[ Tars ARTIFICIAL
f +Pitches
~
~xrixtures ~
~Artificiala Mixtures l Synthetic Products Oxidized Oils
~
!
Pyro bitumens, asphalts, tars, pitches and waxes admit being classified according to their origin as follows : P y r o Bitzivzens.-(a) Derived from the metamorphosis of vegetable growth ( e . g., peat, lignite, bituminous coal and anthracite coal). ( b ) Derived from the metamorphosis of asphalts ‘(e. g., elaterite or wurtzilite, albertite and impsonite). The distinguishing features of the pyro bitumens derived from the metamorphosis of asphalts are as follows : DISTIXGUISHIXGFEATURES OF
Natural-(e. g., mineral tars or maltha). ( b ) Artificial-The soft residues obtained. I . From the distillation of petroleum ( e . g., petroleum tar or soft petroleum asphalt). 2 . From the destructive distillation of organic substances and pyro bitumens; (e. g., pine tar. wood tar, bone tar, coal tar mineral t a r (maltha), petroleum tar, etc.). Pitch.-(a) Satural-Resulting from a slow natural process of metamorphosis known as “mineral pitches” or natural asphalts; e . g.. Trinidad pitch, glance pitch, gilsonite, etc. ( 2 ,j -4rtificialI . Residues from the distillation, oxidation, etc., of mineral oils ; e . g . , petroleum pitch, blown petroleum asphalt, sludge pitch, Dubb’s asphalt, etc. 2 . Residues from the distillation of tars; e . g., coal-tar pitch, brown-coal-tar pitch, coke-oven-tar pitch, blast-furnace-tar pitch, mater-gas-tar pitch, generator-gas-tar pitch, wood-tar pitch, pine-tar pitch, etc. 3. Residues from the distillation of fusible organic substances, the process having been terminated before the actual formation of coke; e . g . , resin pitch, stearin pitch (fatty acid pitches), etc. 4 . Artificial mixtures complying with the above general definition of the term “pitch,” regardless of their origin or composition ( e . g., insulating pitch, Brewer’s pitch, roofing pitch, etc.).
PYRO BITUMENSDERIVED
Elaterite (Wurtzilite) Light brown
1.05-1 .07
K. & S. method Decomposes
Alberiite
Black
1.07-1.10
Decomposes
25 t o 50
Impsonite
Black
1.10-1.20
Decomposes
50 to 5 7
SP. GR. A T 77’ F.
_
DISTINGCISHISGFEATCRES OF M E L T I S G PT. SF’. GR. A T
77’ F.
STREAK
K. & S . method
Brown
1 .06-1 .10
250-350’
Glance Diich
Brown to black
1.10-1.25
2 5 0 - 3 5 0 3 F.
Manjak
Black
1.15-1
Grahaqniie
Black
1
.li5-1.20
F.
3.50450’ F. 450-550°
Percentage 5 to 25
FRACTURE
Conchoidal Hackly Conchoidal Hackly Hackly
I&‘ F L A M E
LUSTRE
Bright Fairly bright Bright Dull Dull
Softens and burns Softens and bums Intumesces Intumesces Decrepitates
ll’ax.-(a) NaturalI . Mineral ( e . g . , ozokerite, ceresine. montan wax, hatchettite, etc.). 2 . Vegetable ( e . g., Japan wax, carnauba wax, etc.). 3. Animal ( e . g . , beeswax, spermaceti, etc.). ( b ) ArtificialI . From the distillation of paraffinaceous petroleum, ozokerite, etc. 2 . From the destructive distillation of lignite (brown coal), paraffinaceous shales, etc TERMSUSED IS PRECEDING DEFISITIOSS Vegetable: These may be of recent formation or ancient formation. I n the latter case, they are termed “fossil.” It is usually conceded, however, that in either event they are of vegetable origin. 2 Naturally Occurring: This excludes artificial products, as for example, certain tars and pitches, synthetic products, artificial mixtures, etc. 1
THE
ISDIVIDCAL
.kSPHILTITES
FIXED CARBON
G i l s o n i f e (Pintaite)
lis
AkSPd.%LTS
CARBOK
AsplzaLtunt.-(a) Natural-Resulting from a slow natural process of metamorphosis, known as natural asphalts (“mineral pitches”). I . Occurring in a fairly pure state. 2 . Associated with a mineral matrix ( e . g., calcareous, siliceous or earthy). ( b ) Artificial-Resulting from the distillation, oxidation, etc., of mineral oils: known as petroleum asphalt (“petroleum pitches”). I . Straight petroleum asphalt. 2 . Cut back. 3. Blown (oxidized), petroleum asphalt. 4. Dubb’s (sulfurized) petroleum asphalt. Asphaltites,-The distinguishing features of the ndividual asphaltites are as follows: I
FROXI
FIXED
MELTING PT.. STREAK
I3
Tar.-(a)
BITUMINOUSA N D RESINOUS SUBSTANCES BITUMIKOUS SUESTANCES RESINOUSSUBSTANCES
2
1I1
the
BETWEEN
I
NATURAL
by
CHEMISTRY
F.
Percentage F R A C T U R E I O t o 20 Conchoidal Hackly 20 to 30 Conchoidal Hackly 30 t o 40 Conchoidal Hackly 40 to 50 Conchoidal Hackly
LUSTRE
Bright Fairly bright Bright Fairly bright Bright Fairly bright to dull Bright Fairly bright to dull
IS FLAME
Softens and flows Softens and flows Variable Variable Softens, splits and burns Softens, splits and bums Decrepitates violently Softens, splits and‘burns
14
T H E J O U R N A L OF I N D U S T R I A L A N D EATGINEERI.VG C H E M I S T R Y
Jan., 1913
m
c
a
8 I
ij \-z
a
B
a
a
i
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a
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.
--
Jan., 1913
THE J O C R * Y A L OF I i Y D U S T R I A L A N D ENGINEERI,YG C H E M I S T R Y
3 Obtained from distillation of bitumens: This includes petroleum pitch, either “straight” or “cut back.” 4 Obtained from the “oxidation” of bitumens: This includes “blown” petroleum pitches. 5 Obtained from the “sulfurization” of bitumens: This includes the so-called “Dubb’s asphalt,” obtained by heating petroleum residues with sulfur. 6 Variable Origin: I t may be of animal, vegetable or mineral origin and includes both natural and artificial products. 7 Hydrocarbon Complex: Often contains oxygen, nitrogen or sulfur derivatives of the hydrocarbons. This excludes vegetable resins, vegetable and animal waxes, etc. Associated with a mineral matrix: This may be calcareous, siliceous, earthy, etc., which is usually present as an impurity. Solutions in essential oils: The essential oils consisting of terpenes. IO Variable Compositions: KO exact chemical composition. Usually mixtures of closely related substances, composed of the elements carbon and hydrogen, together with varying amounts of oxygen, sulfur and nitrogen. May contain hydrocarbons, fats, fatty acids, resin acids, waxes, etc., etc., or mixtures of these. 11 Insoluble in water: This excludes gum resins, carbohydrates, etc. 12 Partly soluble in water: The carbohydrates (“gums”) are the soluble constituents. l 3 Soluble in carbon disulfide, benzol, etc.: This does not take into consideration the mineral constituents present and excludes the pyro bitumens. 14 Relatively insoluble in carbon disulfide, benzol, etc.: This likewise does not take into consideration the mineral constituents present and excludes the bitumens proper, tars, and most pitches. This excludes gaseous and solid bitumens. ’ 5 Viscous: 16 Viscous to semi-solid: This is governed by the amount of essential oil present. 1: Viscous t o solid: Some occur as sticky masses, others as hard and brittle solids a t ordinary temperatures. Plasticity is an inherent or an acquired property. Some are plastic a t ordinary temperatures, others become plastic, under the influence of heat or when combined with suitable fluxes. This excludes the gaseous and liquid bitumens, tars and oleo resins. 1’ Viscous to solid Bitumens and Pyro Bitumens: This includes the hard and relatively insoluble wood-tar pitches, etc. Semi-solid to solid: Usually contains small amounts of essential oils, which govern the consistency. 2” Solid: This excludes gaseous, liquid and viscous substances. 2’ Variable Hardness: This includes gaseous (in the case of bitumens), also liquid, viscous and solid substances. 2 2 Light Colored in Mass: This excludes the mineral resins. 23 Dark Colored in Mass: Csually black. This excludes paraffin (ceresine), and vegetable resins. variable Color in Mass: Color ranges from pure white (paraffin wax), to very dark, almost black (ozokerite and montan wax). 23 Amorphous Structure: I n distinction to crystalline. But sometimes “hackly.” 20 Conchoidal Fracture: Mineral waxes have a waxy lustre, and are, there2: Waxy Lustre: fore, included. 29 Resinous Lustre: This together with the light color is characteristic of the true resins. 29 Son-adherent to slightly adherent feel: I n distinction t o the unctuous feel of waxes. 30 Unctuous Feel: This is characteristic of n-axes. 31 Tarry Odor: Most tars have a characteristic odor, but some mineral tars ( e . g , , maltha, petroleum tars, etc.) are practically free from odor. 32 Extremely susceptible to changes in temperature: Meaning that they pass ~ a p i d h .from the solid t o the liquid srate as the temperature is raised (i. e . , have a high “susceptibility factor”). 33 Fusible: Soften on warming, melt without decomposition, decompose as the temperature is increased, and finally burn with a smoky flame, leaving a carbonaceous residue behind. This excludes the asphaltites, as these are difficultly fusible, and the pyro bitumens as these are infusible (but which, however, decompose and melt a t higher temperatures). 34 Difficultly Fusible: Intermediate between the natural asphalts and pyro bitumens. 35 Infusible: This excludes the bitumens proper, vegetable resins, tars. pitches, etc.
The chart on page 14 shows the relation between bituminous substances, bitumens, pyro bitumens, maltha, asphaltum, asphaltite, tars and pitches ; also between resinous substances, true- resins, oleo resins, gum resins and mineral resins. BOUNDBROOK NEW JERSEY
I5
THE EFFECT OF EXPOSURE ON BITUMENS BY PRhVOST HUBBARD A N D c. s. REEVE I t is a well known fact that in all types of bitumens
changes occur upon aging and exposure. These changes often result in noticeable variations in characteristics which are a t least qualitatively apparent to the casual observer. They may be the result of purely physical phenomena or of chemical reactions which take place either between certain inherent constituents of the bitumens themselves or between the bitumens and some external agent. Thus loss of the lighter oils by volatilization may be considered a purely physical cause of change while molecular rearrangements, inter-reactions and the oxidation of certain constituents are examples of chemical changes. The object of our investigation was to determine the nature of changes due to exposure which take place in various types of bitumens, particularly those used in the treatment and construction of roads and pavements. At the outset i t was realized that to exactly duplicate service conditions in a laboratory test would be impracticable if not impossible but a n attempt \?-as made to approach these conditions as nearly as possible. Eight samples of bituminous road materials were selected for the following experiments as representing the principal types in common use. The results of the usual examination of these materials are given below. These and all other analyses reported in this paper were made according to methods which we have publisheda elsewhere and which, therefore, need not be described here. The form of box in which the exposures were made is shown in Fig. I . This box was made of 3 / / , inch wood, and its interior dimensions were 2 5 X 1 4 ~ X /~
FIO.I.-EXPOSUREBox
,
2 inches. A felt rim surrounded the upper edge and upon this rested a 11, inch plate-glass cover. To provide for some circulation of air, a I / 4 inch slot was cut through each of the sides as shown in the sketch, and a thin board extended from the upper edge a t a n angle of about 45 to prevent dust and rain from entering through the ‘slot. At first strips of cheese-cloth were stretched between the bottom and the edge of the slanting side board, but when it was found that this did not insure perfect freedom from dust, cotton batting was loosely packed beneath the slanting board and against the 1 Paper presented a t the Eighth International Congress of Applied Chemistry. New York, September, 1912. * Bull. 38, Office of Public Roads, U. S. Department of A g k d t u r e .
