摘要:

An arabino-4-O-methylglucuronoxylan (10:14:76), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.1:1:3) have been isolated in yields of 7, 4, and 8% from the wood of amabilis fir (Abies amabilis). The structure of the polysaccharides was established by methylation and periodate oxidation techniques. The xylan () contained side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues, both attached directly to a linear framework of (1 → 4)-linked β-D-xylose residues. The galactoglucomannans (76 and 95) contained (1 → 6)-linked α-D-galactopyranosyl residues attached directly to a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues. Partial hydrolysis of the two hexosans yielded 10 and 13 oligosaccharides, respectively, containing (1 → 4)-β-D-mannose, (1 → 4)-β-D-glucose, and (1 → 6)-α-D-galactopyranose residues. The molecular rotations of a series of mannooligosaccharides corresponded to a value of −54° for the specific rotation of an infinitely long mannan. It is concluded that the main hemicelluloses in amabilis fir wood are the same as those occurring in the wood of gymnosperms from other genera. The same three hemicelluloses are also present in the bark of this species.

ISSN:0008-4042    

DOI:10.1139/v63-188

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

An arabino-4-O-methylglucuronoxylan (10:70:12), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.2:1:3) have been isolated in yields of 8.0, 1.0, and 8.1% from the wood of Engelmann spruce (Picea engelmanni). The xylan consisted of a linear framework of (1 → 4)-linked β-D-xylose residues to which were directly attached single side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues. The galactoglucomannans were both composed of a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues, some of which carried directly attached side chains of (1 → 6)-linked α-D-galactopyranose residues. Partial hydrolysis of the water-soluble galactoglucomannan yielded, among other oligosaccharides, a trisaccharide composed of galactose, glucose, and mannose residues. It is concluded that the main polysaccharides in the wood of Engelmann spruce are the same as those in most other gymnosperms. In the bark of this tree, the water-soluble galactoglucomannan is replaced by one or several polysaccharides of an entirely different composition.

ISSN:0008-4042    

DOI:10.1139/v63-189

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

In the interaction of iodine atoms with butene-2 at 65 °C no addition products are observed although cis–trans isomerization of the butene occurs readily. Iodine atoms have been generated by photolyzing iodine in three spectral regions. The limiting quantum yield of the isomerization reaction is about 0.1 at 4358 Å. The low quantum yield shows that chain reactions, similar to those observed in olefin photochlorinations and photobrominations, do not take place. A mechanism involving initial formation of π-complexes between iodine atoms and butene-2 is tentatively considered.

ISSN:0008-4042    

DOI:10.1139/v63-190

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

In the vapor phase reaction of iodine atoms withn-butenes at 65 °C appreciable double-bond migration takes place in addition to the readily occurring geometrical isomerization. No detectable quantities of iodine-containing hydrocarbons are observed. In contrast to this, appreciable amounts of 1,3-butadiene and the corresponding amounts of hydrogen iodide are formed although direct abstraction of a hydrogen atom from butene by an iodine atom is unlikely in view of the endothermicity of this reaction. Formation of 1,3-butadiene is counterbalanced by its hydrogenation back to the original butene and its isomers and a steady state concentration is reached in the course of the reaction. As a consequence of this balancing of dehydrogenation and hydrogenation steps there is an induction period in the formation of butene-2 in the reaction of iodine atoms with butene-1 and a large part of butene-2 is found to be derived from the butadiene initially produced. To explain the occurrence of the endothermic steps, it is assumed that the initial iodine atom – butene adduct (iodobutyl radical or π-complex) interacts with a second iodine atom. Reaction mechanism is tentatively discussed.

ISSN:0008-4042    

DOI:10.1139/v63-191

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

An X-ray investigation of the compounds aluminum carbide, Al4C3, and aluminum oxycarbide Al4O4C yielded data which differed from that in the A.S.T.M. files. The aluminum carbide pattern was similar in many ways to that calculated by Stackelberg and Schnorrenberg (Z. Physik. Chem., Sect. B,27, 37 (1934). Minor differences occurred in the Al4O4C pattern.

ISSN:0008-4042    

DOI:10.1139/v63-192

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Mesquite gum was subjected to the Smith procedure involving periodate oxidation, reduction, and mild hydrolysis. The mainD-galactose chain was fragmented to a greater extent than expected. The quantity of glycerol formed indicated the presence of a considerable number of 1 → 6 linkages while the formation of threitol showed the presence of 1 → 4 linkages. Several small oligosaccharides terminated by a glycerol residue were isolated together with an oligosaccharide of D.P. 30. Further periodate oxidation of the latter gave a product with D.P. 24 which was in turn oxidized to a compound consisting largely ofD-galactose and glycerol. Reduction of the acidic fraction gave mainly 2-O-methyl-D-erythritol.

ISSN:0008-4042    

DOI:10.1139/v63-193

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The static dielectric constant of liquid ethylene oxide has been measured between 158 and 286 °K. The hydrate of ethylene oxide exhibits a dispersion–absorption region characterized by static dielectric constants about one-third as large as those of ice and by relatively large "high-frequency" dielectric constants (ϵ1 = 7.5 at 0 °C). This region may be approximately described as a circular arc locus, but may be represented somewhat better by a superposition of two (or three) semicircular dispersions. In either case, the activation energy for the relaxation of water molecules, to which this region is ascribed, is ca. 6.7 kcal/mole, except at low temperatures, where it becomes smaller. Experimental values of ϵ1agree roughly with those calculated for comparatively rapid orientation of ethylene oxide molecules in the cavities of the hydrate. Such orientation may account for absorption maxima observed at 11 Mc/sec and above 100 Mc/sec at 90 °K.

ISSN:0008-4042    

DOI:10.1139/v63-194

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

2,6-Bis-(alkylamino)-2,5-heptadien-4-ones have been prepared by the action of aqueous amines on (1) 3-acetyl-4-hydroxy-6-methyl-2-pyrone (dehydroacetic acid), (2) 3-(1-alkylimino-ethyl)-4-hydroxy-6-methyl-2-pyrone, (3) 3-carboxy-2,6-dimethyl-4-pyrone, (4) 2,6-dimethyl-4-pyrone, (5) 2,6-dihydroxy-2,5-heptadien-4-one. The reactions are facile and proceed smoothly at temperatures near, or slightly above, room temperature. In (1) the first products are 3-(1-alkyliminoethyl)-4-hydroxy-6-methyl-2-pyrones, followed by the 2,6-bis-(alkylamino)-2,5-heptadien-4-one. The other reactions yield only the latter product, but in all cases it decomposes to the 4-pyridone at higher temperature, or on prolonged reaction or by the action of acid.The 2,6-bis-(alkylamino)-2,5-heptadien-4-ones are pale yellow compounds with a slight violet fluorescence. Infrared, n.m.r., and ultraviolet spectra are consistent with an open-chain, internally hydrogen-bonded structure.

ISSN:0008-4042    

DOI:10.1139/v63-195

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The measured distortion polarizations of a group of bis-arylmercury compounds show that they do not exhibit exalted atom polarizations. The apparent orientation polarization of each is appreciable. Two of them, which are substituted symmetrically with methoxyl or nitro, exhibit moments expected from the rotation which is generated in such substances. By comparison of bis-4-bromophenylmercury202with the analogue containing the ordinary isotopic mixture of mercury the apparent moments are shown to be unrelated to nuclear asymmetry. The conclusion is unaltered that the apparent moments of bis-arylmercury compounds are due to effective non-linearity in the C—Hg—C bond.

ISSN:0008-4042    

DOI:10.1139/v63-196

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v63-197

出版商:NRC Research Press    

年代:1963

数据来源: NRC