Earl J. Roberts

Removal of mercury from aqueous solutions by nitrogen-containing chemically modified cotton

The authors thank 0. Clifton Taylor, Raymond Tenorio, and Eugene A. Cardiff for the preparation and a generous supply of PAN. Note Added in Proof. Chemiluminescence generated by bubbling PAN through a solution of triethylamine in acetone (1% V/V) was approximately twice as intense as that produced in the vapor phase reaction. The results were more reproducible in the liquid phase than in the vapor phase. Therefore, the liquid phase chemiluminescence seems to be more suitable for atmospheric monitoring applications.

Effect of base concentration upon the reactivities of the hydroxyl groups in methyl d-glucopyranosides

Abstract The anomeric methyl D -glucopyranosides were treated with N,N-diethylaziridinium chloride in various molarities of aqueous sodium hydroxide at variable ionic strength and constant ionic strength. It was found that the extent of reaction of the hydroxyl groups at C-2, C-3, and C-4 decreased with increasing concentration of base. Reaction at the C-6 hydroxyl group remained essentially constant with increasing concentration of base. Neither varying the ionic strength nor the concentration of reagent affected the distribution of substituents at any given concentration of base.

Selective Accessibilities of Hydroxyl Groups in the Microstructure of Cotton Cellulose1

The reactions of 2-chloroethyldiethylamine with the hydroxyl groups at C-2, C-3, and C-6 of the d-glucopyranosyl unit of cotton cellulose were investigated as a means of evaluating the relative accessibilities of these hydroxyl groups in heterogeneous reactions of fibrous cellulose. The relative rate constants for reactions of the individual types of hydroxyl groups were determined from reactions of cellulose in solution and from reactions of disordered cellulose in heterogeneous systems. Quantitative determinations of the distributions of 2-(diethylamino)ethyl substituents in the mono-substituted d-glucopyranosyl units involved hydrolysis of the chemically modified cellulose to glucose and substituted glucoses followed by gas-liquid chromatographic analysis. The relative accessibilities of the hydroxyl groups at C-2 and C-3 vs those at C-6 were estimated for crystalline celluloses by employing the relative rate constants (noted above) together with the experimentally measured distributions of substituents resulting from heterogeneous reactions of crystalline celluloses and appropriate kinetic expressions. The relative accessibilities of the hydroxyl groups at C-2, C-3, and C-6 in cellulose in strong mercerizing media approach those of cellulose in solution. In media of lower concentration of sodium hydroxide (i.e., 4 N or 13.9%), selective accessibilities of the individual types of hydroxyl groups become evident, and these selective accessibilities become pronounced in sodium hydroxide solutions of still lower concentrations (e.g., N and 2 N).

Effects of selected reaction conditions and structural variations on the distribution of 2-(diethylamino)ethyl groups on d-glucopyranosyl residues of 2-(diethylamino)-ethylated cellulose, starch, and the anomers of methyl 4,6-O-benzylidene-d-glucopyranoside

Abstract The reactivities of the hydroxyl groups in cellulose, starch, and the anomers of methyl 4,6- O -benzylidene- d -glucopyranoside with 2-(diethylamino)ethyl chloride have been investigated under identical conditions in ( a ) aqueous and ( b ) nonaqueous medium. For cotton cellulose, the relative distribution of 2-(diethylamino)ethyl groups on the 2-, 3-, and 6-hydroxyl groups in the mono- O -[2-(diethylamino)ethyl]- d -glucopyranose fraction of the hydrolyzate was found to be independent of the D.S. Cellulose treated with 2-(diethylamino)ethyl chloride in p -dioxane showed a higher ratio of substituents on the 2- and 3-hydroxyl groups, relative to the 6-hydroxyl group, than resulted when the reaction was conducted in an aqueous medium. Consideration of these results on the basis of the fraction of substituents in each of the three positions showed that the increase in substitution on the 2-hydroxyl group is accompanied by a decrease in substitution at the 6-hydroxyl group and little change in that at the 3-hydroxyl group. Starch follows a similar pattern, but the increase in substitution on the 2- and 3-hydroxyl groups, relative to the 6-hydroxyl group, is more pronounced than for cellulose under identical conditions. The fractions of substituents on the 2-hydroxyl groups increases as a result of reaction in p -dioxane. The increase in substitution at the 2-hydroxyl group is accompanied by a decrease in that at the 6-hydroxyl group, but here a substantial increase in substitution at the 3-hydroxyl group occurs. With regard to the change in fraction of substitution at the 3-hydroxyl group with change in the reaction medium, methyl 4,6- O -benzylidene-β- d -glucopyranoside behaves similarly to cellulose, and the α- d anomer behaves similarly to starch.

The Relative Reactivities of the Hydroxyl Groups of Cotton Cellulose—A Progress Report1

Major preceding studies of the distribution of substituents in cellulose have been reviewed. Over-all results indicate that the highest degree of reaction occurs at the hydroxyl group on C-2 in the case of the irreversible Williamson syntheses involving reagents of small molecular size. Pronounced preferential reaction occurs at the hy droxyl group on C-6 in the case of reversible reactions and with increasing molecular size of reagent. The relative reactivities of the hydroxyl groups on C-2, C-3, and C-6 of the D(1→4)- β-glucopyranosyl unit of cotton cellulose have been explored with three chemical agents. Predominant reaction of cotton cellulose occurs at the primary hydroxyl group on C-6 in the case of the reversible Michael addition of methyl vinyl sulfone (i.e., 2-0- : 3-0- : 6-0- = 0.20: 0.03: 1.00), at the hydroxyl groups on C-2 and C-6 in the case of the irreversible reaction with diethylaminoethyl chloride (1.27 : 0.35 : 1.00), and at the hydroxyl groups on C-6 and C-2 in the case of the irreversible Williamson synthesis with sodium allyl sulfate (0.7:0.2:1.0). The D-(1→4)-α-glucopyranosyl unit of dextrin (employed as a soluble model compound for cellulose) undergoes reversible esterification with formic acid most rapidly and to the highest equilibrium level at the primary hydroxyl group on C-6.

Structure of Reagent Residues in Cotton Cellulose Modified with Tris(1-aziridinyl)phosphine Oxide

Several samples of tris(1-aziridinyl)phosphine oxide (APO)-modified cotton were prepared with 5.8-14.6% APO in corporation. The samples were degraded by acid hydrolysis and attempts were made to isolate the expected 0-(2-amino ethyl)-D-glucopyranoses and 0-[N-(2-aminoethyl)-2-aminoethyl]-D-glucopyranoses by a variety of techniques. Neither of these glucose derivatives could be detected in the hydrolyzates; however, the hydrolyzates were found to contain a considerable quantity of ethanolamine along with N-(2-aminoethyl)ethanolamine and complex products resulting from reaction of the functional group at C-1 of glucose and the amino compounds derived from the APO during acid hydrolysis. The ethanolamine in the hydrolyzates of two samples of APO-modified cotton was estimated to account for about 85% of the total nitrogen in the samples. The N-(2-aminoethyl)ethanolamine was estimated to account for about 5% of the original nitrogen. The remaining 10% was in the form of polyethylenimines, N-glucosylamine complexes, and glucose substituents.

Substantivity of Polyethylenimines on Cotton Fabric

Samples of cotton print cloth were impregnated with 10% solutions of polyethylenimines of various molecular weights, line-dried or oven-dried, and then subjected to ten standard laundering and drying cycles. Analysis for retention of the polyethylenimine (PEI) on cotton fabric through a series of ten laundering cycles showed that substantivity increased with increasing molecular weight of PEI. The effect of oven-drying of PEI-cotton fabric was to increase the retention of PEI over that on line-dried samples; the magnitude of the increase was tmoportional to the moledular weight of the PEI. Fabric properties are described.

Enzymatic Hydrolysis as a Source of Structural Information on Cellulose

An apparatus and a procedure are descrihed to facilitate saturation of accessible surfaces of solid cellulose with cellulase and to facilitate removal of inhibiting byproducts from the sphere of reaction. Fibrous cotton cellulose (lattice I) was observed to undergo enzymatic hydrolysis (cluture filtrate from T. Viride, 50°C) in a rate curve similar to that resulting from mineral acid hydrolysis (2.5 N HCl, reflux) but with a time scale greater by a factor of 24. Other similarities be tween enzymatic and mineral acid hydrolyses of this fibrous cellulose are brought out.

N,n-diethylaziridinium chloride as a coreactant catalyst for reactions of n-methylol reagents with cellulose

The use of N,N-diethylaziridinium chloride (DAC) as a coreactant catalyst for the reaction of cellulose with several N-methylol compounds has been investigated. This catalyst was effective in promoting reaction between cotton and all of the four methylol derivatives tested but especially effective in promoting the reactions of dimethylolethyleneurea and methylated trimethylolmelamine with cotton cellulose. These two cross-linking agents could be used in a delayed- cure process with DAC as the catalyst. Little reaction occurred with either of these reagents during delay periods up to 33 days and no increases in recovery angles were found in the delayed and uncured samples. The delayed-but-cured samples showed crease-recovery angles equal to those achieved in immediate cures.

Evidence for Two Types of Accessible Surfaces in Fibrous Cotton

Diethylaminoethyl (DEAE)-cellulose, prepared at low DS and without change in crystallinity from that of the original cottons, was subjected to hydrolysis with 2.5 N HCI for various lengths of time ranging from 20 min to 5 hr. The yield of DEAE-hydrocellulose (insoluble fraction) ranged from 90.5% at 20 min to 79.2% at 5 hr. Throughout the hydrolysis, the percent nitrogen in the solubilized fraction was triple that in the insoluble fraction. Gas-liquid chroma tographic analysis to determine the distribution of substituents in the solubilized and insoluble fractions showed that the ratio of substituents in the 2-0- and 6-0-positions was higher in the insoluble fraction than in the solubilized frac tion. The 3-0-/6-0-ratio was higher in the solubilized fraction than in the insoluble fraction. The significance of these results as supporting evidence for two types of accessible surfaces of crystalline elementary fibrils in fibrous cotton cellu lose is discussed.