New ionic polymers by cellulose functionalization

The unique structure and reactivity of cellulose opens up various possibilities for the design of advanced materials based on this biomacromolecule. In the present feature the state of the art of selected cellulose functionalization reactions is discussed adequately considering own research results. In particular, new synthesis paths to ionic cellulosics, both with controlled functionalization patterns and unconventional combinations of different functional groups (hydrophilic-lipophilic), as well as new synthesis concepts are presented. An important approach to new cellulosics is the reaction via an induced phase separation with solid alkali hydroxide particles. Starting from solutions of cellulose in N,N-dimethylacetamide/LiCl or from organo-soluble cellulose derivatives of different hydrolytic stability dissolved in dimethyl sulfoxide, subsequent etherification and esterification yield cellulose products of unconventional functionalization patterns and properties. Not only reactions directed towards the hydroxyl groups—the primary reactive sites—is given attention but also nucleophilic displacement reactions at the carbon atoms appear as synthesis tool to new polysaccharide materials.     

Evaluation of the Synthesis of Soluble Aromatic Cellulose Carbonates of Low Degree of Substitution

The synthesis of soluble cellulose phenyl carbonates of low degree of substitution (DS, as low as 0.3) can be realized by using phenyl chloroformates with reactivity‐controlling moieties in the aromatic ring or by conversion of 6‐O‐triphenylmethyl cellulose. It is assumed that the primary hydroxyl group may yield to cross‐linking during the introduction of the phenyl carbonate moieties. Thus, for the first time soluble cellulose phenyl carbonates of low DS are accessible that are useful for the preparation of novel cellulose derivatives by reaction with nucleophilic reagents in particular amines.     

Strukturaufklärung der bei der Addition von 2-Cyano-2-propylradikalen an p-Tolyl- und 4-Cyclohexylphenyl-methacrylat entstehenden Produkte mittels 1H NMR- und Massenspektren

The chromatographically pure products, gained on the suppression of polymerisation of p-tolyl or 4-cyclohexylphenyl methacrylates ( 1, 2 ) by a great excess of 2-cyano-2-propyl radicals, could be isolated in a total yield of 95 to 100%. The structure of these products was established by ¹H NMR and mass spectroscopy. There are p-tolyl or 4-cyclohexylphenyl 4-cyano-2-(2-cyano-2-propyl)-2,4-dimethylvalerate ( 1a, 2a ), p-tolyl or 4-cyclohexylphenyl 2-(2-cyano-2-methylpropyl)acrylate ( 1b, 2b ), p-tolyl or 4-cyclohexylphenyl 4-cyano-4-methyl-2-(2-cyano-2-methylpropyl)valerate ( 1c, 2c ), p-tolyl or 4-cyclohexylphenyl 4-cyano-2,4-dimethylvalerate ( 1d, 2d ), and p-tolyl or 4-cyclohexylphenyl 4-cyano-2,4-dimethyl-2-pentenoate ( 1e, 2e ( 2f )). It is possible to give a scheme of reactions on the suppression of the radical polymerisation.     

Soluble and film-forming cellulose derivatives with redox- chromogenic and enzyme immobilizing 1,4-phenylenediamine groups

Cellulose architectures with redox-chromogenic properties and anchor groups for the immobilization of biomolecules have been prepared by reaction of p-toluenesulfonic acid esters of cellulose (tosylcellulose, DS 2.3) with 1,4-phenylenediamine (PDA) in dimethyl sulfoxide (DMSO) solution at 100°C. The degree of substitution (DS) of the PDA groups and remaining p-toluenesulfonate (tosylate) groups, and thus the properties of the 6-deoxy-6-(4-aminophenyl)amino-2(3)-O-tosylcellulose (PDA cellulose) formed, can be adjusted by varying the PDA molar equivalents and the reaction time. Most of PDA celluloses are soluble in DMSO and N,N-dimethylacetamide (DMA) and form transparent films. The redox-chromogenic properties of PDA cellulose have been demonstrated by oxidation of the PDA groups with H₂O₂ to the corresponding diimine (λ_max = 480 nm) and by oxidative coupling with phenol to the corresponding indophenol (λ_max = 595 nm). The suitability of the PDA units as reactive anchor groups was shown by the immobilization of enzymes like glucose oxidase, peroxidase, and lactate oxidase. The highest enzyme activity achieved for peroxidase immobilized with glutardialdehyde on a PDA cellulose film was 0.165 U/cm².     

New polyurethanes based on diphenylmethane diisocyanate and 1,4:3,6-dianhydrosorbitol, 1. Model kinetic studies and characterization of the hard segment

1,4:3,6-Dianhydrosorbitol (DAS) seems to be an interesting reagent for the synthesis of polyurethanes. In the present work, the kinetics of the reaction of DAS with a monoisocyanate (p-tolyl isocyanate, p-TI) and with a diisocyanate (4,4′-diphenylmethane diisocyanate, MDI) were studied with the help of a chromatographic method (size exclusion chromatography, SEC). When the condensation reaction is performed in tetrahydrofuran (THF) solution, with dibutyltin dilaurate (SnDBDL) as catalyst, DAS exhibits two equireactive hydroxyl groups. The reaction rate can be well described by a second-order equation modified to include catalysis by the formed urethane functions. MDI and DAS were then condensed using two different experimental procedures (bulk and solution polycondensation in THF, in the presence of SnDBDL), and the characteristics of the resulting polyurethanes were compared. Bulk polycondensation led to an amorphous polymer, whereas the polyurethane prepared in solution was semi-crystalline. In both cases, we obtained a very high glass transition temperature ( ≈ 186°C). The synthesis of samples with various polymerization degrees gave a better understanding of the molecular weight distribution of segmented polyurethanes based on MDI and DAS.     

Effective preparation of cellulose derivatives in a new simple cellulose solvent

Cellulose with a degree of polymerization up to 650 can be dissolved in dimethyl sulfoxide containing 10 to 20% (w/v) tetrabutylammonium fluoride trihydrate without any pretreatment within 15 min at room temperature. The new solvent can be classified as a non‐derivatizing one as concluded from ¹³C NMR measurements. The solvent can be used as reaction medium for the homogeneous functionalization of the polymer. Cellulose esters are prepared very effective by transesterification reactions. The functional groups are distributed in the order expected for a homogeneous conversion, i. e., a preferred reaction at the primary hydroxyl groups occurs. Moreover, carboxymethyl cellulose with a preferred functionalization at the primary hydroxyl groups and a non‐statistic content of the different repeating units was accessible.     

Polymerization of bis[4-bis(2,3-epoxypropyl)aminophenyl]methane. Identification of new derivatives of 3-hydroxy-1,2,3,4-tetrahydroquinoline

Bis[4-bis(2,3-epoxypropylamino)phenyl]methane ( 3 ) was shown to undergo homopolymerization when heated without or with an accelerator such as N,N-dimethylbenzylamine ( 10 ). When 3 was polymerized without accelerator, no ether formation was found. A new type of curing process involving opening of the epoxy ring by reaction at the phenyl ring in ortho position to the tertiary amino substituent allows one to explain the formation of compounds containing the 3-hydroxy-1,2,3,4-tetrahydroquinoline moiety. The corresponding derivatives 4–7 were isolated for the first time and their structures established by different spectroscopic methods such as ¹H, ¹³C, 2D δ-δ NMR, and FT-IR. Intermolecular reaction at the orthocarbon of the tertiary amino group with an epoxy group may explain the resin formation by curing 3 without accelerator. Polymerization of 3 with accelerator 10 led to polyetherification. This result may be explained in terms of difference in the reactivity of the tertiary amines 3 and 10 towards the epoxy group. The former gives an unstable “zwitterion” by reaction at the nucleophilic carbon, subsequently leading to the stable hydroquinoline system by proton transfer. The latter also gives an unstable “zwitterion” by reaction at the nucleophilic nitrogen, however, it induces epoxy ring-opening polymerization due to the lack of intramolecular stabilization. Moreover, the results suggest that the hydroxyl functions, formed in the absence of an accelerator, do not react with epoxides under the studied conditions.     

Caractérisation de réactions primaires de dégradation oxydante au cours de l'autoxydation des polyoxyéthylènes à 25°C: Étude en solution aqueuse avee amorçage par radiolyse du solvant. II. Arguments pour un mécanisme monomoléculaire de décomposition des radicaux peroxyles

Cationic copolymerizations of furfural were carried out with several vinyl monomers. No copolymers were obtained with some hydrocarbon comonomers. At low temperatures furfural copolymerized with vinyl ethers selectively through the aldehyde group. On the other hand, deeply-colored copolymers of complex structures were formed at higher temperatures (ca. 0°C). Three typical vinyl ethers (p-tolyl vinyl ether, dihydropyran, and divinyl ether) were selected as comonomers, and their copolymerization behaviour studied in detail. The monomer reactivity ratios for furfural (M₁) and p-tolyl vinyl ether (M₂) were r₁ = 0,15 ± 0,15, r₂ = 0,25 ± 0,05. The furfural (FF) contents were fairly independent of the monomer feeds when dihydropyran (DHP) and divinyl ether (DVE) were used as comonomers: 37–47% for FF-DHP copolymers and 40–50% for FF-DVE copolymers. More than half of the second vinyl groups were consumed in the FF-DVE copolymers indicating the formation of 1,3-dioxane rings as in the case of benzaldehyde-DVE copolymers.     

Kinetische untersuchungen zur reaktionsfähighkeit von chlormethylgruppen in methylendiphenolen

The chloromethyl derivatives of 16 differently substituted methylenediphenols were synthesized for the first time. To compare their reactivity, the solvolysis in methanol and the animolysis with an excess of p-nitroaniline in dimethyl sulfoxide were studied kinetically at 25°C. The rate constants for the methanolysis do not differ very much, beside of the fact that para-chloromethyl derivatives react about 100 times faster than ortho-chloromethyl derivatives. However, for the aminolysis a large acceleration up to 10³ was found for compounds having both hydroxyl groups in ortho-position to the methylene bridge. Obviously, the cleavage of the O? H bond, which occurs in the rate determining step of the aminolysis, is strongly favoured by an intramolecular hydrogen bond between the phenolic hydroxyl groups.     

Studies on chitin, 8. Modification reaction of chitin in highly swollen state with aromatic cyclic carboxylic acid anhydrides

Reaction of partially deacetylated chitin with aromatic cyclic carboxylic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic dianhydride was successfully carried out under almost homogeneous conditions in organic aprotic solvents using highly swollen precipitates of water-soluble chitin with about 50% deacetylation. The resulting amic acid-chitins were converted into the corresponding imide-chitins by heating. In addition to imidization, this heat treatment also promotes removal of acid anhydrides reacted at the hydroxyl group giving rise to the formation of selectively N-substituted derivatives. These novel chitin derivatives exhibit a much improved solubility in organic solvents and aqueous alkaline solutions. As anticipated, the imide-chitins, derived from trimellitic anhydride and pyromellitic dianhydride, showed reactivity toward amine under heterogeneous conditions, and the reaction capacities toward p-chloroaniline were determined to be 4,2 · 10^?4 and 4,6 · 10^?4 mol · g^?1, respectively.     

Branching in high molecular weight polyhydroxyethers based on bisphenol A

The polyaddition reaction of bisphenol A with the diglycidyl ether of bisphenol A is treated statistically on the basis of cascade theory to describe the branching process. The chain lengthening step is based on the reaction of the epoxide functional group with the phenolic hydroxyl group and leads to the formation of a 1,3-diphenoxy-2-propanol link. The peculiar feature of this polyaddition reaction is the possibility of further addition of an epoxide to a secondary hydroxyl group to form branched molecules. This branching reaction does not, however, lead to a loss of hydroxyl groups since a new secondary hydroxyl group is created when an epoxide functional group reacts with a secondary hydroxyl group. Closed analytic expressions are derived for the weight-average (M_w) and number-average (M_n) molecular weights in terms of the mole ratio R = m_b/m_a and the extents of reaction of the functional groups α(phenolic hydroxyl), β(epoxide), and p(branching), i.e. the probability p that an epoxide group has reacted with a secondary hydroxyl group, where m_b and m_a are the mole fractions of the diglycidyl ether of bisphenol A and of bisphenol A, respectively. Consideration of a simple kinetic mechanism shows that α,β and ρ are related to the ratio b = k₂/k₁, where k₁ and k₂ are the rate constants of the chain lengthening step and the chain branching step, respectively. The equations derived for M_w and M_n as a function of a α allow the determination of the branching probability p (or the kinetic rate constant ratio b). An equation for the gel point (M_w → ∞) is given which states a relationship between α_c and p_c where the subcript c refers to the critical point of gelation. Thus location of the gel point and measurement of α_c, either directly or by extrapolation on samples taken prior to gelation, enables p to be measured.     

Addition reactions of isocyanides and isocyanostyrenes with organolithium compounds

The addition reactions of isocyanides and o- and p-isocyanostyrenes with n-butyl lithium have been studied by ultraviolet spectrometry. The reaction of n-butyl lithium with cyclohexyl and phenyl isocyanides at 0°C gives in n-hexane an α.α-adduct R? N?C(Li)? Bu together with small amounts of a dimeric product, the amount of which increases with increasing concentrations of isocyanide. These compounds were characterized spectrometrically and identified by their reaction products after addition of methanol. With p-tolyl isocyanide hydrogen abstraction from the p-methyl group competes with the α.α-addition; the concentrations of both organolithium derivatives p-CH₃? C₆H₄? N?C(Li)? Bu and p-LiCH₂? C₆H₄? N?C increase with increasing amounts of butyl lithium. With o- and p-isocyanostyrenes the addition of butyl lithium occurs unexpectedly at the vinyl group, however without further vinyl polymerization. This peculiar behavior of the isocyanostyrenes has been observed spectrophotometrically in n-hexane containing 20 volume % dibutyl ether, and was confirmed by their reactions towards living polystyryl lithium end groups.     

Formaldehyde resins. 93. Reaction rate of polynuclear p-cresol-formaldehyde-condensate with formaldehyde in acidic media

The linear poly nuclear p-cresol-formaldehyde condensates up to octabody^ll were syntHesized, and the rates of their reaction with formaldehyde in ca. 80% dioxane in the presence of perchloric acid were measured. The reaction rates of the one to four nuclear condensates (H? 1? H ～ H? 4? H) were approximately double of those of higher nuclear condensates (H? 5? H ～ H? 8? H). The abrupt decrease of the rate of tetrabody(H? 4? H) to the pentabody (H? 5? H) was explained by two considerations: The first is the rolling up form of the higher molecular condensate where the one end (i.e. the reactive site) is hidden by the molecule itself and the second is the formation of hydrogen bonds between all the hydroxyl groups to decrease the reactivity of the aromatic substitution with a methylol cation.     

Diphenylmethane diisocyanate (MDI)-induced asthma: evaluation of the immunologic responses and application of an animal model of isocyanate sensitivity

A worker developed two episodes of severe asthma 90 min after cut ting a polyurethane plate made of diphenylmethane diisocyanate (MDI) using a rapidly turning carbide blade. Intradermal skin testing with MDI-human serum albumin (MDI-HSA) and p-tolyl isocyanate-HSA (p-TMI-HSA) were positive at 0.002 mg/ml. Control subjects showed no reaction at 2 mg/ml. Bronchial provocations of the worker with MDI-HSA and p-TMI-HSA, made 1 year after the occupational asthmatic episode, were negative at 10 mg/ml. Bronchial reactivity to methacholine decreased toward normal during a 2-year follow-up. RAST using MDI-HSA or p-TM I-HSA were strongly positive when compared with binding by sera from atopic controls which contained the same amount of total IgE. RAST titres decreased during a 1-year follow-up. In the MDI-HSA RAST, inhibition studies indicated specificity of antibodies for MDI-HSA. In the p-TMI-HSA RAST. p-TMI-HSA was a very effective inhibitor whereas MDI-HSA was not. These results indicated the formation of at least two distinct groups of IgE antibodies: those reactive with MDI. and those reactive with p J-TMI determinants. Guinea pigs immunized with MDI formed antibodies with specificities similar to those of the patient. We conclude that the worker had occupational asthma accompanied by the formation of specific IgE antibodies of the specificities. The causal relationship of the antibodies to the occupational asthma remains uncertain.     

Determination of the Kinetic Constants of the Telomerization of 10‐Undecenol with Alkyl Hydrogenphosphonate

Summary: The telomerization of 10‐undecenol with alkyl hydrogenphosphonate was studied in order to synthesize telomers of different molecular weights. The study showed that telomers from 10‐undecenol could be obtained despite the fact that the double bond has a low reactivity. The kinetic constant Kp²/K_Te was determined to be 7 × 10^?4 l · mol^?1 · s^?1 at 135 °C and the transfer constant C_T was 0.057. These values are normal for a low activity telogen such as hydrogenphosphonate and for slightly reactive monomers like 10‐undecenol.

SEC chromatogram of telomers obtained in the reaction of 10‐undecenol addition.     

Spectroscopic measurements on spontaneously polymerizing styrene, 2. The estimation of the reactivity of the two Diels-Alder-isomers towards polymer radicals

Spectroscopic measurements at 335 nm on polymerizing styrene have been carried out with spontaneously polymerizing as well as dibenzoyl peroxide (BPO)-initiated bulk systems. The evidence for the formation of two Diels-Alder-intermediates, 1a and 1b , out of which only 1a seems to be capable to produce initiating radicals by reaction with the monomer, can also be derived from the development of the absorption, characteristic for the intermediates, during the BPO-initiated polymerization. From the dependence of the overall rate constants of consumption of 1a , k_2,a[M] , and 1b , k_2,b[M] , on the rate of polymerization the reactivity of 1a and 1b towards polymer radicals can be estimated. Whereas 1b , the less reactive intermediate, seems to be mainly consumed by polymer radicals through copolymerization, chain transfer being unimportant, (the rate constant of consumption of 1b by polymer radicals, k_3,b, relative to the constant of chain propagation k_p ranges from 2,1 at 60°C to 3,2 at 80°C) the corresponding ratio for 1a , k_3,a/k_p, which goes from 113 at 80°C to 143 at 60°C, is supposed to represent primarily the constant of chain transfer of 1a in styrene polymerization. Under the condition of spontaneous polymerization the reaction with polymer radicals contributes 16% (for 1a ) and 5–8,5%, depending on temperature (for 1b ), to the overall rate of consumption of the intermediates. The stationary concentration of 1a , the isomer which accordingly is solely responsible for initiation as well as chain transfer in spontaneous styrene polymerization, is calculated to range from 5,2·10^?6 mol l^?1 at 60°C to 8,5·10^?6 mol l^?1 at 80°C.     

Rate constants for elementary reactions of the radical polymerization of methyl 2-(benzyloxymethyl)acrylate as polymerizable acrylate bearing large substitutents

Methyl 2-(benzyloxymethyl)acrylate (MBZMA) which was synthesized by reaction of methyl 2-(bromomethyl)acrylate with benzyl alcohol was radically homo- and copolymerized. MBZMA polymerized as fast as methyl methacrylate despite of the presence of a large 2-substituent. The absolute rate constants for propagation and termination were evaluated from the direct determination of the steady state concentration of the propagating radical by electron spin resonance spectroscopy at 60°C: k_p = 182 dm³ · mol^?1 · s^?1 and k_t = 1,6 · 10⁶ dm³ · mol^?1 · s^?1. It was deduced from the magnitude of the rate constants that the balance of the slow propagation and termination allows the formation of a polymer. Evaluation of the cross-propagation rate constants in the copolymerization with styrene revealed that primarily the steric effect of the benzyloxymethyl group reduced the reactivity of the polymer radical and that the electronwithdrawing character of the 2-substituent prevailing the steric effect enhanced the monomer reactivity toward the polystyrene radical.     

Condensation polymerization of 2,2′-diiodobiphenyl-4,4′-dicarbonyl dichloride with some mono- and diamino compounds

Several potentially thermostable polyamides were prepared. 2,2′-Diiodobiphenyl-4,4′-dicarboxylic acid and its diacid chloride 1 were synthesized. The latter was condensed with several amines, e.g., aniline, p-toluidine, p-chloroaniline, and 2-aminopyridine, to prepare model compounds of polyamides testing the reactivity of the diacid dichloride 1 towards various amines, and to compare their spectra with those of the polymers. The polyamides themselves were prepared by solution and melt condensation of diacid chloride 1 with the following diamines: p-phenylenediamine, m-phenylenediamine, 2,6-diaminotoluene, benzidine, bis(4-aminophenyl)-methane, 4,4′-diaminobiphenyl sulfone, and 3,3′-diaminobenzophenone. The solubility of the polyamides in different solvents and their inherent viscosities were also measured. The values of the inherent viscosity were in the range of 0,1–1,9. The UV, IR, and ¹H NMR spectra of the prepared polyamides were recorded. The melting points of the polymers were found to be higher than 360°C and the thermogravimetric curves showed that the polymers are stable up to 400°C in air.     

Inhibition of adjuvant-induced arthritis in the hyperuricemic rat

In man, there is a strong negative correlation between gout and rheumatoid arthritis. To investigate this apparent mutual exclusion, we studied the influence of oxonate-induced hyperuricemia on the development of adjuvant arthritis in male Wistar rats.The results indicate that in the primary reaction (inflammation of the injected paw) the differences are weak (0.10>p>0.05) between normouricemic and hyperuricemic rats. In hyperuricemic rats the secondary reaction (induced polyarthritis) is delayed and significantly reduced (p<0.005). Non-immunologic carrageenin paw edema is not statistically different between the two groups (p>0.25).Experimental hyperuricemia in rats seems to influence essentially the secondary, cell mediated, reaction without affecting the acute inflammatory phases.     

Réaction époxide amine: Réactivité du sulfonyl-4,4′ dianiline vis-à-vis du groupement époxy

Mechanism and kinetics of the polycondensation of 4,4′-sulfonyldianiline ( 2 ) with 2,3-epoxy-1-phenoxypropane ( 1 ) were analysed in the absence or presence of a catalyst [N,N-(dimethyl)-benzylamine or BF₃ complex]. Chemical data obtained by ¹³C NMR and HPLC show that secondary reactions (homopolymerisation, reaction of hydroxyl groups with the epoxy groups) take a prominent part.