摘要:

Exhaustive extraction with anhydrous liquid ammonia removed 8.0% of wheat straw holocellulose. Acetamide was isolated from the extract and identified as the dihydrogen bromide salt. A polyuronide fraction, making up 1.3% of the holocellulose, was isolated and shown to consist ofD-xylose,L-arabinose,D-glucose,D-galactose, andD-glucuronic acid in approximate molar ratios of 11:3:3:1:2.5. Analysis and hydrogenation of the noncarbohydrate portion of the liquid ammonia extract showed it to consist of low molecular weight degradation products among which methylamine was identified. A separate experiment showed that anhydrous liquid ammonia degraded an isolated polyuronide by 8.4%; all components of the polyuronide were equally affected.

ISSN:0008-4042    

DOI:10.1139/v52-033

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Kinetic evidence has been obtained to indicate that, in toluene, the reaction between silver and triphenylmethyl chloride is a tarnishing reaction involving the growth of a silver chloride film on silver. Logarithmic, linear, and parabolic rates were observed, as well as a characteristic, very sudden decrease in reaction rate under certain conditions. The film thicknesses at which most of these phenomena occurred were those predicted by the Cabrera–Mott theory for the oxidation of metals.

ISSN:0008-4042    

DOI:10.1139/v52-034

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Dicumarol (3,3′-methylenebis(4-hydroxycoumarin)) has been synthesized labeled with C14in the 2-position. Starting with active barium carbonate of specific activity 1.6 µc.per mgm., the intermediate compounds diethyl carbonate-1-C14and 4-hydroxycoumarin-2-C14were prepared. Subsequent reaction of the latter compound with aqueous formaldehyde yielded dicumarol-2-C14. The specific activity of the final product, once recrystallized from cyclohexanone, was 4.3 × 105counts per min. per mgm. corrected for geometry and absorption. The expired carbon dioxide from a mouse injected with this C14-labeled product was collected and found to contain no radioactivity. This indicated that, in this animal, the 2-carbon of dicumarol does not enter into a metabolic process whereby it is expired as carbon dioxide.

ISSN:0008-4042    

DOI:10.1139/v52-035

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The preparation and ultraviolet absorption spectra of a number of methyl ethers and acetates of purpurogallin are given. The following derivatives of purpurogallin are, to our knowledge, not mentioned in the literature: a mono-acetate, m.p. 182-183 °C.; a diacetate I, m.p. 159–160 °C; a diacetate II, m.p. 208–209 °C.; a triacetate, m.p. 161.5–162.5 °C.; a monomethyl ether diacetate, m.p. 156–157 °C.; a dimethyl ether diacetate, m.p. 194-196 °C. Comparison of the ultraviolet absorption spectra with those determined for derivatives of known structure suggested the positions of the acetyl groups in the new substances now prepared.

ISSN:0008-4042    

DOI:10.1139/v52-036

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The alcohol–glycerol method for the determination of free calcium oxide in solid systems can be used to determine the monoxides of strontium and barium with a similar degree of precision. The determination of calcium ethylate by this method shows promise. The soluble magnesium salts, magnesium chloride and magnesium acetate, interfere with the determination of the oxides through a replacement reaction liberating magnesium oxide. The chlorides of calcium, strontium, and barium increase the initial titer obtained in the determination of the monoxides of calcium and strontium, but have no such effect in the determination of barium oxide. For calcium oxide this increase in titer for equimolecular concentrations of the chlorides is in the ascending order: barium, strontium, calcium; for strontium oxide the effectiveness is in the reverse order. The method involves reactions between the monoxides and glycerol to form titratable metal triglycerol hydroxides and possibly two nontitratable products, the mono- and di-glyceroxides of the metals. The relative amounts of these compounds appear to be determined by the physical state of the oxide, the period of heating, the ratio of alcohol to glycerol, and the amount of water present.

ISSN:0008-4042    

DOI:10.1139/v52-037

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The reduction of 2-methoxyalkylmercuric halides by hydrazine hydrate is thought to proceed through mercuri-bis-2-methoxyalkane, which decomposes to give 2-methoxyalkarie radicals. These radicals may lose or gain a hydrogen atom to form 2-methoxyalkene or alkane. The reaction seems to be definitive for structure proof. Thebis-mercurial from the (α) 2-methoxycyclohexylmercuric chloride which is formed directly from cyclohexene is less stable than the diastereomeric (β)bis-mercurial, which can be purified by distillation. Conversion of this (β)bis-mercurial to pure β-2-methoxycyclohexylmercuric chloride shows that this reaction occurs by direct replacement. The hydrazine reduction may be used to convert β-1-chloromercuri-2-methoxy-1,2-diphenylethane (fromtrans-stilbene) to theα-diastereomer. Since the β-isomer in this case is more readily hydrolyzable than the α isomer, and each isomer may be converted cleanly back to its parent alkene, the series of reactions provides a method of convertingtrans- intocis-stilbene.

ISSN:0008-4042    

DOI:10.1139/v52-038

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

A novel decarboxylation of uronic acids by merely heating the material without the use of a solvent or added catalyst is described. At approximately 255 °C. decarboxylation for uronic and polyuronic acids and salts within 15 min. reaction time is nearly quantitative. Vigorous dehydration occurs simultaneously, the residue corresponding basically to a 5-carbon skeleton that contains 1.5 atoms of oxygen. Other products of the reaction are minor and include carbon monoxide, and traces of acid and oils. Sugar acids, such as gluconic and ascorbic, are not as extensively decarboxylated. The reaction is employed for analysis of several nitrogen dioxide oxidized celluloses and starches and the results are in good agreement with those given by titration and the 12% hydrochloric acid method.

ISSN:0008-4042    

DOI:10.1139/v52-039

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

2-5-Octamethylene tetrahydrophthalic anhydride does not form even a trace of the corresponding phthalic anhydride on dehydrogenation, but partly dissociates back into cyclododecadiene and maleic anhydride. 2-5-Nonamethylene tetrahydrophthalic anhydride dehydrogenates with considerable difficulty.

ISSN:0008-4042    

DOI:10.1139/v52-040

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The stannic chloride catalyzed anomerization of the pentaacetyl-D-gluco-pyranoses in chloroform solution is specific for the C1-acetoxy group. The reactions involve complete dissociation of the C1-carbon atom to acetoxy group bond with an intermediate formation of carbonium ions. The initial step of thebetatoalpharearrangement is a rapid dissociation, involving the participation of the C2-acetoxy group, to a resonance-stabilized carbonium ion with the lactol carbon atom occupied in the α-configuration. The rate-controlling step in the reaction appears to be the rearrangement of this ion to other ions which are capable of recombining with acetate ion to yield the α-acetate. The α-acetate is highly stable, as compared to the β-anomer, and the dissociation of the C1-carbon atom to acetoxy group bond is the rate-controlling step in its rearrangement. The stability of the α-acetate toward a variety of acidic reagents which readily dissociate the β-form is pointed out. For example, although the α-acetate is highly stable toward titanium tetrachloride, the reaction of the β-anomer with this reagent, to yield tetraacetyl-β-D-glucopyranosyl chloride, is extremely fast. This product is unstable under the reaction conditions used and rearranges to the α-form at a measurable rate. 1,2,3,4-Tetraacetyl-β-D-glucopyranose with stannic chloride in chloroform solution yielded triacetyl-D-glucosan <l, 5 > β <1, 6>.The alkaline hydrolysis of triacetyl-D-glucosan <1, 5> α <1, 2> yieldedD-glucosan <1, 5> β <1, 6>. The mechanisms of these reactions are discussed.

ISSN:0008-4042    

DOI:10.1139/v52-041

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Measurements of self-diffusion in aqueous solutions of sodium dihydrogen phosphate have been made using P32as tracer. The method involves the preparation of two similar solutions differing only in the fact that one is "labelled" by means of the P32isotope. A capillary cell is filled with the radioactive solution and immersed in a relatively large volume of inactive solution, maintained at a constant temperature. After diffusion has proceeded for a measured length of time, the cell is removed and the radioactivity of the liquid remaining in it measured by counting. The self-diffusion coefficient may be calculated from the length of the capillary cell, the period of diffusion, and the ratio of the final activity to the original activity. The method was checked by repeating some work on the self-diffusion of Na+in sodium iodide solution. Self-diffusion measurements were made with sodium dihydrogen phosphate solutions of several concentrations between 1.0 and 10−4molar.

ISSN:0008-4042    

DOI:10.1139/v52-042

出版商:NRC Research Press    

年代:1952

数据来源: NRC