THE AMERICAN CHEMICAL SOCIETY

DIVISION OF ORGANIC CHEMISTRY

(Continued)

Symmetrical tribromphenylpropiolic acid and its reaction with acetic anhydride: ROBERT CHAMBERS. Phenylpropiolic acid condenses with acetic anhydride to form a phenylnaphthalene dicarboxylic anhydride. This reaction holds for derivatives of phenylpropiolic acid where there is a free ortho hydrogen. It was desired to investigate the action of acetic anhydride on a di ortho substituted phenyl propiolic acid. The above acid was prepared from meta nitro cinnamic acid as follows: reduction with zinc and hydrochlorie acid gave meta amido hydrocinnamic acid. Bromination and subsequent diazotization in boiling ethyl alcohol gave 2.4.6 tribromhydrocinnamic acid. Heating to 145° in a sealed tube with bromine gave aa dibrom 2.4.6 tribromhydrocinnamic acid. The latter with hot alcoholic potash gave 2.4.6 tribromphenylpropiolic acid. acetic anhydride the above acid does not condense to a phenylnaphthalene derivatives but forms an anhydride which may be hydrolyzed to the original acid.

With

The reactions of alpha anthroquinonesulfonic acids with mercaptans: E. EMMET REID, COLIN M. MACKALL and G. E. MILLER. Sodium anthroquinone-alpha-monosulfonate and the 1.5 or 1.8 disulfonates react readily with mercaptans in water solution to replace the sulfonic acid group by SR to give anthraquinone alkyl thio-ethers or dithio-ethers, a-C1H,O,.SR, 1, 5-CHO2(SR), and 1.8-CH,O,(SR). The disulfonates may give the intermediate alkyl thio-ether sulfonate.

The polymers of pinene: G. B. and C. J. FRANKFORTER and E. R. KRYGER.

Contribution to our knowledge of the chemistry of calcium carbide: G. B. FRANKFORTER and A. E. STOPPEL.

A new lactone from oil of orange: FRANCIS D. DODGE. Essential oils of citrus species, obtained by expression, on standing generally deposit solids from which certain lactones derived from coumarin have been obtained. In the present communication is described a new lactone of rather unusual properties obtained from the sediment of West Indian oil of orange. It forms colorless needles (m. p. 88-90°) easily soluble in alcohol and ether, slightly so in ligroin. Optical rotation is about -38° in alcohol. On acidifying an alka

line solution it yields a crystalline acid (m. p. 151°) from which no crystalline salts could be obtained. It yields no acetyl derivative, and can not be reconverted into the lactone. It is readily oxidized by permanganate. The lactone, like coumarin, yields a crystalline compound with bisulfite. Analysis indicates the empirical formula: C16H1803.

The bromination of 2-amino-p-cymene: ALVIN S. WHEELER and IRA W. SMITHEY. Pure p-cymene, obtained from spruce turpentine, was nitrated and the 2-nitro-p-cymene was reduced with Sn and HCI. The acetyl derivative of 2-amino-p-cymene in CCl solution was boiled with bromine. Bromo derivative, needles, m. 122°; yield 60 per cent. Hydrolysis gave free amine, liquid, b. 169°-170° at 20 mm., da 1.3012, пD" 1.5781. HCl salt, plates, m. 206°-210°. HBr salt, plates, m. 205°. Diazobromoaminocymene, canary yellow needles, m. 146°-148° (decomp.). Oxidation of bromoacetylaminocymene with neutral permanganate gave a toluic acid derivative, m. 213°. Hydrolysis with acid gave the bromoamino acid, needles, m. 151°; HCl salt, plates, m. 190° (decomp.). No bromoamino toluic acid of this description could be found in the literature. The Br atom appears to be in the 3 position.

m.

New derivatives of 2, 3, 8-tribromo-5-hydroxy-1, 4-naphthoquinone: ALVIN S. WHEELER and T. M. ANDREWS. Action of NaOH on the tribromoquinone (4) gave the 2, 3-dibromo-5, 8-dihydroxy1, 4-naphthoquinone (B), which, reduced with Zn and H.SO, gave 2, 3-dibromo-1, 4, 5, 8-tetrahydroxynaphthalene, greenish needles, m. 164°166°. Tetracetyl derivative, yellow needles, 149°-150°. Acetyl derivative of B, yellow prisms, m. 197°. Methyl ether of A, yellowish red plates, m. 209-210°. Ethyl ether of A, yellow needles, m. 134°-136°. Aniline derivative of A (Br No. 8 replaced), purplish chip-like erystals, m. 235°. A is converted by Zn and H.SO, into the trihydroxy derivative, yellowish needles, m. 106°— 107°; triacetyl derivative, colorless prisms, m. 220°. Br. No. 8 in 4 is replaced by Cl with HC and alcohol, golden bronze plates, m. 152°; acetyl Ketone rederivative, yellow prisms, m. 160°. agents on A do not give well defined products.

The bromination of 2-amino-p-cymene: ALVIN S. WHEELER and I. W. SMITHEY. (By title.)

The production of furfural by the action of superheated water on aqueous corn cob extract: F. B. LAFORGE. (By title.)

DIVISION OF AGRICULTURAL AND FOOD CHEMISTRY

C. E. Coates, chairman.

T. J. Bryan, secretary. Suggestions for more rapid and exact methods of analyses for the cheese factory: S. K. ROBINSON. Some problems of the pure food manufacturer: H. A. NOYES. The preserver of fruit and fruit products has two important problems to solve: (1) The obtaining of a high quality and uniform fruit supply each year, and (2) the processing of fruit in such a way that its natural properties are retained. The pure food manufacturer's inability to accomplish these two things up to the present has allowed the artificial flavor and color manufacturer to develop his products and befuddle the taste of the average consumer. The plans and organization of one large concern, to study the production of quality fruits and to apply research methods to its business, were given.

Variations in the Concord grape during ripening: H. A. NOYES, H. T. KING, J. H. MARTSOLF. Variations in the Concord grape during ripening that are of interest to the juice and jam manufacturer were investigated. Results show a gradual increase in sugar content, a decrease in total acids and irregularities in tannin and coloring matter. Weather conditions were an important factor affecting sugar content, warm days and cool nights seeming to be the optimum condition for developing sugar.

The absorption of copper from the soil by potato plants: F. C. Cook. Insoluble copper compounds present in a Bordeaux spray containing an excess of lime and present in Pickering spray containing no excess of lime, also a solution of sulfate of copper, were added to the soil near the roots of potato plants in equal strengths and amounts at various intervals during the growing season. Samples of vines, tubers and soil were taken for analyses at frequent intervals. The leaves of the plants grown in the soil receiving the insoluble copper, i.e., the sprays, held the largest part of the copper, the roots but little and the stems an intermediate amount. The tubers contained but traces of copper. Where the soil was treated with the copper sulfate solution the roots were injured and the normal metabolism of the vines interfered with. The tubers from these vines were small and the vines stunted. In these plants the roots held more copper than the leaves. The soluble copper sulfate added directly to the soil caused injury to the plants while the insoluble

The

copper compounds of the sprays did not. extra lime of the Bordeaux spray did not reduce the amount of copper absorbed by the plants compared with the results on the Pickering plants. Where the sprays and copper sulfate solution were added to the soil directly practically the same amounts of copper were recovered from the soil samples. Samples of soil from sprayed potato fields showed but minute amounts of copper.

Pickering Bordeaux sprays: F. C. COOK. Analysis of the Jerusalem artichoke: A. T. SHOHL. The Jerusalem artichoke, Helianthus tuberosus, gives the analysis:

Water Nx6.25 Fat Carb. Fiber Ash Per cent...79.0 3.1 .2 16.5 .8 1.1 The wastage by peeling is 31 per cent., the hydrogen ion concentration (colorimetric) pH 5.0. The carbohydrate is inulin, as determined by polariscope and quantitated after inversion by Benedict's solution. Experiments show it is utilized, and not excreted by diabetics. The nitrogen is largely extracted with boiling water. This nonprotein fraction represents 71.5 per cent. of total nitrogen. Of the water soluble non-protein nitrogen 26 per cent. is free amino acid nitrogen and 12 per cent. ammonia nitrogen.

Measuring soil toxicity, acidity and basicity: R. H. CARR.

What puts the "pop" in pop corn? R. H. CARR. (Lantern.)

The rate of oxidation of lime-sulfur: C. A. PETERS and A. L. PRINCE. The rate of oxidation of lime-sulfur is largely independent of the concentration and also of the temperature up to about 80°, when the rate is increased in all but the very dilute solutions.

A color test for "remade" milk: OSCAR L. EVENSON.

Effect of aging on lecithin-phosphoric acid determination of egg noodles: R. C. HUMMELL. The results of these experiments indicate that aging does have considerable effect on the lecithin-phosphoric acid determination in egg noodles. By the end of six months this value had decreased to less than two thirds of the original value and in eighteen months had decreased to one half or less than one half of the original amount. Inasmuch as considerable time may elapse from the time at which egg noodles are manufactured until they reach the consumer, it would seem to be quite in

error to judge the egg content by the value obtained in the aforesaid determination.

Peanut by-products: J. B. REED.

Some factors governing the crystallization of lactose in ice cream: HARPER F. ZOLLER and OWEN E. WILLIAMS. A curve is presented as a result of experimental evidence which serves to separate those mixes which will produce sandiness from those which will not, and is based upon the relationship existing between the protein-serum solids concentration and the concentration of lactose within the mix. It is erroneous to calculate the concentration of lactose on the water basis since the total water in the mix is not available to the lactose because of the competition of the other solids. The effect of the proteins within the mix is not to repress the crystallization of lactose, but they act oppositely in increasing concentration. Because of its slow rate of crystallization lactose hydrate is subject to much supercooling and oversaturation. Protein has very little effect upon its rate of growth. The solubility of lactose hydrate according to the best of experimental deductions is 11.15 per cent. at 0° C. In an ice cream mix containing 10 per cent. fat, 14 per cent. of cane sugar and 65 per cent. of water, the above value for lactose reduces to about 8.9 per cent. calculated on the water basis.

A rotating thermocouple and cold junction designed for temperature studies in horizontal power ice cream machines: HARPER F. ZOLLER. A sensitive and experimental thermocouple is described and illustrated which has been designed for the purpose of accurately measuring the temperature of the ice cream mix within the freezer when the

latter is rotating at full speed. By maintaining an ice-water cold junction affixed to the shaft of the freezer along with the thermocouple junctions the small temperature differences within the freezer can be measured with an accuracy of .02° C. This latter is also made possible by the use of a five junction copper-constantan thermocouple (of fine wire for small temperature lag effect) and a potentiometric setup embracing a galvanometer of low internal resistance with a potentiometer of microvolt capacity. The unique feature of the instrument is the method of conducting the small e.m.f. from the rapidly rotating shaft to the potentiometer without frictional thermoelectric effects. The instrument has been in regular service for a number of months, has given no trouble, and has measured the rapidly fluctuating temperatures within the mix simply and accurately.

Cases of supercooling during the freezing of ice cream mixes: HARPER F. ZOLLER and OWEN E. WILLIAMS. By the use of the rotating thermocouple we have examined the point of separation of ice in a variety of mixes. The measurements were made in a commercial ice cream machine of the Miller type with a capacity of five gallons. The freezing point lowering of the mix was not in harmony with the calculated value, but showed a high supercooling in the mix even in the presence of the swiftly moving beaters and scrapers. The addition of fine particles of substances to promote the formation of crystal nuclei prevented the supercooling of the mix and consequently the freezing was done in a shorter time, and the product was smoother. Both fat and gelatin seem to reduce supercooling in the average mixes. When sand is added to an ice cream mix containing 10 per cent. fat and 0.5 per cent. of gelatin ice begins to separate at only a slightly higher temperature when the brine is at 10° F. during the freezing process. If the brine is much lower there is a greater difference in the supercooling effect when no sand is present in the above mix. When mixes are frozen which have been made from evaporated milk containing lactose crystal nuclei and they have not been destroyed by pasteurization, or other means, no supercooling ocA great deal of importance is attached to the degree of supercooling and its influence upon the texture of the ice cream as it comes from the freezer.

curs.

Black discoloration in canned sweet potatoes: EDW. F. KоHMAN. The black discoloration which occurs in canned sweet potatoes begins in the bottom of the can where there is usually a semiliquid starch paste which affords close contact with the can. Eventually it may penetrate the entire content of the can. The black formation is due to the combination of iron dissolved from the can with a tannin-like substance in the potatoes. This is localized to a considerable extent just beneath the peel. But as there is also some throughout the potato and especially about the center no change in present methods of peeling would be of advantage. Tannins do not form black compounds with iron unless the latter is in its highest state of oxidation. As air is essential to bring it into this condition, the necessity of tight seams in canned sweet potatoes is emphasized. CHARLES L. PARSONS, Secretary

TYPES OF VALENCE

FROM the theory proposed by G. N. Lewis in 1916 and subsequently extended by the writer, it is clear that the term valence has been used in the past to cover what we may now recognize as three distinct types of valence, viz.:

1. Positive valence: the number of electrons an atom can give up.

2. Negative valence: the number of electrons an atom can take up.

3. Covalence: the number of pairs of electrons an atom can share with its neighbors.

It was shown that these fundamental conceptions of valence as well as the actual numerical values of each type of valence for most of the elements could be derived from a few postulates regarding the structure of atoms. The following method of deriving these relationships, however, is not only much simpler than that previously given by the writer, but throws a new light on the relationships between the different types of valence.

We will take for granted the Rutherford type of atom, which consists of a positive nucleus surrounded by a number of electrons equal to the atomic number of the atom. We will also assume that Coulomb's law applies to the forces between the charged particles in the atom, but at the same time will recognize the existence of repulsive forces in atoms which prevent the electrons from falling into the nucleus. For the present purpose, however, it is immaterial whether the repulsive force is a dynamic force (centrifugal force) such as that assumed by Bohr, or is a static force as postulated by G. N. Lewis, J. J. Thomson or recently by the writer.2

We shall need to make only 3 postulates in

1 Langmuir, Jour. Amer. Chem. Soc., 41, 926 (1919), and Jour. Ind. Eng. Chem., 12, 386 (1920). 2 SCIENCE, 53, 290, Mar. 25, 1921.

regard to the structure of atoms, and these are consistent with those previously proposed.

Postulate 1.-The electrons in atoms tend to surround the nucleus in successive layers containing 2, 8, 8, 18, 18 and 32 electrons respectively.

The word atom is used in the broader sense which includes charged atoms (ions). If the number of electrons in an atom is such that they can not all form into complete layers in accord with Postulate 1, the extra electrons remain in the outside layer as an incomplete layer which we may designate as the sheath of the atom. Every electrically neutral atom must contain a number of electrons equal to the atomic number of the nucleus. If the outside layer of such an atom is nearly complete, the tendency expressed by Postulate 1 may cause a few additional electrons to be taken up in order to complete the layer, thus forming a negatively charged atom or ion. In such a case we may say that the sheath has been completed.

In the following discussion it is important to keep in mind this distinction between sheath and outside layer. Every incomplete outside layer which occurs normally is a sheath, but a complete outside layer may or may not be a sheath. The following definition will make this clearer. The sheath of any atom (or atomic ion) consists of all the electrons in the outside layer provided that this layer is incomplete when the atom is electrically neutral. Thus atoms of the inert gases (neon, argon, etc.) and ions such as Na+, Ca++, etc., have no sheaths for the outside layers of these atoms consist of electrons which already form a complete layer in the neutral atom. The sodium atom, however, has an incomplete sheath containing one electron, while the fluorine atom has an incomplete sheath of 7 electrons. The fluorine ion, on the other hand, has a complete sheath of 8 electrons.

The inert gases are the only elements whose neutral atoms have no sheaths, or in other words have all their electrons arranged in complete layers in accordance with Postulate 1. In all other atoms, the tendency expressed by

this postulate can only be satisfied by an interaction between atoms involving a rearrangement of the electrons. This is to be regarded as the fundamental cause of chemical action and it is by such interaction that chemical compounds are formed.

When as the result of such rearrangement of electrons, the sheath of an atom has become complete, we may speak of the atom as a complete atom. Similarly if the interaction between atoms leads to complete satisfaction of the tendency of Postulate 1, so that all the atoms become complete, we may say that a complete compound is formed. We shall see that there are some factors which may oppose the formation of complete atoms and counteract the tendency of Postulate 1. In such cases incomplete atoms and compounds may result.

According to Postulate 1, the first complete layer in any atom consists of two electrons close to the nucleus. Let us call this stable pair of electrons a duplet and let us broaden the definition of duplet to include any pair of electrons which is rendered stable by its proximity to one or more positive charges. We may now state the second postulate.

Postulate 2.-Two atoms may be coupled together by one or more duplets held in common by the completed sheaths of the atoms.

Let us now analyze the conditions that must be fulfilled if the interaction between atoms is to result in the formation of a complete compound.

A given group of neutral atoms may interact to complete their sheaths in two ways:

1. By transfer of electrons.

a. Atoms having sheaths containing only a few electrons may give up these extra electrons to other atoms.

b. Atoms having nearly complete sheaths may take up electrons from other atoms.

2. By sharing duplets.

Atoms may share duplets with other atoms (Postulate 2) and thus complete their sheaths with fewer elec