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1986 Volume 3 Issue 5
1986, 3(5): 1-5
Abstract:
When a microporous hydrophobic membrane separates two aqueous solutions at different temperature, a selective mass transfer across the membrane can be obtained. Membrane distillation may be used to solve some waste water problems, chemical separation and recovery, and concentration of aqeuous solution of substance which is sensitive to high temperature, with simple equipment. It is particularly attractive and promising. In this paper, the mechanism of the membrane distillation is described, and some information about membrane distillation of aqueous solution and other applications are introduced.
When a microporous hydrophobic membrane separates two aqueous solutions at different temperature, a selective mass transfer across the membrane can be obtained. Membrane distillation may be used to solve some waste water problems, chemical separation and recovery, and concentration of aqeuous solution of substance which is sensitive to high temperature, with simple equipment. It is particularly attractive and promising. In this paper, the mechanism of the membrane distillation is described, and some information about membrane distillation of aqueous solution and other applications are introduced.
1986, 3(5): 6-13
Abstract:
Pervaporation is a membrane separation process which can be used to fractionate liquid mixture. In this paper the mechanism of pervaporation is described. The separation of ethanol-water mixture by pervaporation is of great importance for the production of ethanol from biomass. The membranes for separation of ethanol water mixture can be divided into two types:hydrophilic and hydrophobic. Some physical methods have been used to improve the pervaporation process. The tendency of developmentof pervapration membranes, as indicated by author, is from homogeneous, asymmetric to composite membrane.
Pervaporation is a membrane separation process which can be used to fractionate liquid mixture. In this paper the mechanism of pervaporation is described. The separation of ethanol-water mixture by pervaporation is of great importance for the production of ethanol from biomass. The membranes for separation of ethanol water mixture can be divided into two types:hydrophilic and hydrophobic. Some physical methods have been used to improve the pervaporation process. The tendency of developmentof pervapration membranes, as indicated by author, is from homogeneous, asymmetric to composite membrane.
1986, 3(5): 14-17
Abstract:
The inhibition of benzidine on the photodecomposition reaction of 4,4'-diszidobiphenyl has been studied. It was found that the photo-decomposition of 4, 4'-diazidobiphenyl could not come through to an end and confirmed that it was benzidine which inhibited the photo-decomposition of 4,4'-diazidobiphenyl.
The inhibition of benzidine on the photodecomposition reaction of 4,4'-diszidobiphenyl has been studied. It was found that the photo-decomposition of 4, 4'-diazidobiphenyl could not come through to an end and confirmed that it was benzidine which inhibited the photo-decomposition of 4,4'-diazidobiphenyl.
1986, 3(5): 18-21
Abstract:
The dependence of viscoclastic properties on the molecular weight and MWD of cis-1,4-polyisoprene has been studied with the methods of GPC and stress relaxation. The results show that the relaxation modulus and the maximum relaxation time of Ln-PIR depend not only on the molecular weight, but also on the MWD.The value of K changes with MWD, but the β is essentially constant in the relationship of τm=KMwβ. Higher chain entanglement density leads to the non Newtonian effect of Ln-PIR.Hence,the relationship between τm and Mw deviates from the 3.4th power rule. This may be corrected with the density value of chain entanglement. The low molecular weight fractions act as a diluent in the chain entanglement networks. The samples with broader MWD have higher critical molecular weight Mc ofentanglement networks.
The dependence of viscoclastic properties on the molecular weight and MWD of cis-1,4-polyisoprene has been studied with the methods of GPC and stress relaxation. The results show that the relaxation modulus and the maximum relaxation time of Ln-PIR depend not only on the molecular weight, but also on the MWD.The value of K changes with MWD, but the β is essentially constant in the relationship of τm=KMwβ. Higher chain entanglement density leads to the non Newtonian effect of Ln-PIR.Hence,the relationship between τm and Mw deviates from the 3.4th power rule. This may be corrected with the density value of chain entanglement. The low molecular weight fractions act as a diluent in the chain entanglement networks. The samples with broader MWD have higher critical molecular weight Mc ofentanglement networks.
1986, 3(5): 22-27
Abstract:
In this paper, the reaction activity of impregnated microspheroidal CuCl2/Al2O3 catalyst using in oxygen based ethylene oxychlorination to prepare ethylene dichloride was studied. XRD, TPR and pulse reaction technique proved that the impregnated catalyst has identical active phase of CuCl2 with commercial coprecipitated catalyst,though the copper present in the later at first is in the form of Cu2(OH)3Cl, but it changes into CuCl2 by HCl which is presented in the reacting gas as the oxychlorination takes place. The copper content and its state of distribution on the surface of γ-Al2O3 car-rier appear important in the activity development of the catalyst. They also show a serious influence on the fluidity in fluidized bed reaction. The impregnated catalyst is simple to prepare and its cost is low. Catalyst with 9%(wt) copper content may be used instead of the coprecipitated catalyst having 13% (wt) of copper.
In this paper, the reaction activity of impregnated microspheroidal CuCl2/Al2O3 catalyst using in oxygen based ethylene oxychlorination to prepare ethylene dichloride was studied. XRD, TPR and pulse reaction technique proved that the impregnated catalyst has identical active phase of CuCl2 with commercial coprecipitated catalyst,though the copper present in the later at first is in the form of Cu2(OH)3Cl, but it changes into CuCl2 by HCl which is presented in the reacting gas as the oxychlorination takes place. The copper content and its state of distribution on the surface of γ-Al2O3 car-rier appear important in the activity development of the catalyst. They also show a serious influence on the fluidity in fluidized bed reaction. The impregnated catalyst is simple to prepare and its cost is low. Catalyst with 9%(wt) copper content may be used instead of the coprecipitated catalyst having 13% (wt) of copper.
1986, 3(5): 28-33
Abstract:
The synthetic method and properties of a series of new network polymeric crown ethers were reported in this paper. Eight network polymeric crown ethers were prepared by the net-polymerization of bisglycidyl ether, ethylene glycol bisglycidyl ether, diethylene glycol bisglycidyl ether triethylene glycol bisglycidyl ether and tetraethylene glycol bisglycidyle ther in the presence of BF3·OEt2 or (i-Bu)3Al as catalyst. The studied network polymeric crown ethers have good cation-complexing ability and effective catalytic activity in the nucleophilic substitution of PhOK with n-BuBr.
The synthetic method and properties of a series of new network polymeric crown ethers were reported in this paper. Eight network polymeric crown ethers were prepared by the net-polymerization of bisglycidyl ether, ethylene glycol bisglycidyl ether, diethylene glycol bisglycidyl ether triethylene glycol bisglycidyl ether and tetraethylene glycol bisglycidyle ther in the presence of BF3·OEt2 or (i-Bu)3Al as catalyst. The studied network polymeric crown ethers have good cation-complexing ability and effective catalytic activity in the nucleophilic substitution of PhOK with n-BuBr.
1986, 3(5): 34-38
Abstract:
Semi-and fully-interpenetrating polymer networks (IPN) based on polyurethane/MMA were prepared. The effects of component ratio, amount of cross-linking agent and the structure of the semi-and fully-IPN on mechanical properties were observed.The δp and Me of the IPN were determined by means of swelling measurement.Experimental results indicated that Mc is an important factor influencing physical properties of IPN system.
Semi-and fully-interpenetrating polymer networks (IPN) based on polyurethane/MMA were prepared. The effects of component ratio, amount of cross-linking agent and the structure of the semi-and fully-IPN on mechanical properties were observed.The δp and Me of the IPN were determined by means of swelling measurement.Experimental results indicated that Mc is an important factor influencing physical properties of IPN system.
1986, 3(5): 39-43
Abstract:
The potentiometric curves of 25 basic dyes and 19 quaternary ammonium salts titrated with orange Ⅳ (10-3M or 10-4M) have been recorded. A method for evaluating the potentiometric titration curves was suggested and their superiority sequences were established. it was found that some of the curves may be applied in electrochemical analysis with higher sensitivity, and the structure of basic dyes and quaternary ammonium salts exerts an influence on the titration curve. The superiority sequences of the titration curves would give a possible approach to find new electroactive substances for anion-selective electrodes.
The potentiometric curves of 25 basic dyes and 19 quaternary ammonium salts titrated with orange Ⅳ (10-3M or 10-4M) have been recorded. A method for evaluating the potentiometric titration curves was suggested and their superiority sequences were established. it was found that some of the curves may be applied in electrochemical analysis with higher sensitivity, and the structure of basic dyes and quaternary ammonium salts exerts an influence on the titration curve. The superiority sequences of the titration curves would give a possible approach to find new electroactive substances for anion-selective electrodes.
1986, 3(5): 44-48
Abstract:
Five different capacitor grade aluminum foils ranging in purity from 99.97 to 99.999 per cent Al were electrolytically etched in hydrochloric acid under 50Hz A.C. with positive half cycle rectified. The impurities in aluminum were found to influence markedly on the results. The etch morphology of extra pure foil exhibits a deep layer of regularly distributed cubic pits, giving a higher surface area gain.When the impurities in aluminum increased, the etch pits grew larger and the new pits developed only along the (100) direction at the later stage of etching, forming tappered cubic tunnels and having a lower surface area gain. The results were interpreted by the potential oscillographs and were considered to be related to the ability of passivation of aluminum foil with different purity. Because the acidity inner the pits was higher than that in the bulk solution, the etch film formed was thin and transparent, quite differing from the thick precipitated one as in the case of full A.C. etching, which gives a higher pH value owing to the hydrogen evolution during the negative half cycle. Some additives and their effects were also investigated.
Five different capacitor grade aluminum foils ranging in purity from 99.97 to 99.999 per cent Al were electrolytically etched in hydrochloric acid under 50Hz A.C. with positive half cycle rectified. The impurities in aluminum were found to influence markedly on the results. The etch morphology of extra pure foil exhibits a deep layer of regularly distributed cubic pits, giving a higher surface area gain.When the impurities in aluminum increased, the etch pits grew larger and the new pits developed only along the (100) direction at the later stage of etching, forming tappered cubic tunnels and having a lower surface area gain. The results were interpreted by the potential oscillographs and were considered to be related to the ability of passivation of aluminum foil with different purity. Because the acidity inner the pits was higher than that in the bulk solution, the etch film formed was thin and transparent, quite differing from the thick precipitated one as in the case of full A.C. etching, which gives a higher pH value owing to the hydrogen evolution during the negative half cycle. Some additives and their effects were also investigated.
1986, 3(5): 49-53
Abstract:
The extraction behaviour of indium with dimethylheptyl acetamide from hydrochloric acid medium has been studied. The extractability is found to increase with the concentration of HCl. It is confirmed by an application of the slope method and chemical analysis that the extraction of In with N503 from hydrochloric acid solution can be represented as follows: In(a)3++H(a)++4Cl(a)=+nnN503(O)⇌HInCl4·nN503(O) The solvation number n of the extracted species varies with the concentration of hydrochloric acid. IR and NMR data show that the indium is extracted in the form of HInCl4 into the organic phase of N503. Under the condition of [HCl]<2N the extractability of galliun, Indium and thallium with N503 was found to be in the following order: Tl(Ⅲ) >Ga(Ⅲ) >In(Ⅲ)
The extraction behaviour of indium with dimethylheptyl acetamide from hydrochloric acid medium has been studied. The extractability is found to increase with the concentration of HCl. It is confirmed by an application of the slope method and chemical analysis that the extraction of In with N503 from hydrochloric acid solution can be represented as follows: In(a)3++H(a)++4Cl(a)=+nnN503(O)⇌HInCl4·nN503(O) The solvation number n of the extracted species varies with the concentration of hydrochloric acid. IR and NMR data show that the indium is extracted in the form of HInCl4 into the organic phase of N503. Under the condition of [HCl]<2N the extractability of galliun, Indium and thallium with N503 was found to be in the following order: Tl(Ⅲ) >Ga(Ⅲ) >In(Ⅲ)
1986, 3(5): 54-57
Abstract:
The influence of the concentration of KOH and Al(OH)4- and current density on the passivation of Al has been investigated using galvanostatic charging method. It was shown that the relation between i and τ=1/2 obeys the well known non-steady state diffusion equation (i-iL)τ=1/2=(1/2)nF(CAlS -CAl0)(D(Al)π)1/2=k (1) The i~τ-1/2 curve was composed of two straight lines with different slops and CAlS, DAl have been calculated from the results based on equation(1). The results indicate that when current density is low the passivation of Al electrode is controlled by the diffusion of Al(OH)4- ions from the surface into the solution and an anodic passivation film is formed as a result of the precipitation of Al(OH)3 or Al2O3 from the super-saturated Al(OH)4- solution near the electrode surface. At higher current densities, the formation of the anodic passivation film is caused by both electrochemical reaction and the diffussion-controlled precipitation.
The influence of the concentration of KOH and Al(OH)4- and current density on the passivation of Al has been investigated using galvanostatic charging method. It was shown that the relation between i and τ=1/2 obeys the well known non-steady state diffusion equation (i-iL)τ=1/2=(1/2)nF(CAlS -CAl0)(D(Al)π)1/2=k (1) The i~τ-1/2 curve was composed of two straight lines with different slops and CAlS, DAl have been calculated from the results based on equation(1). The results indicate that when current density is low the passivation of Al electrode is controlled by the diffusion of Al(OH)4- ions from the surface into the solution and an anodic passivation film is formed as a result of the precipitation of Al(OH)3 or Al2O3 from the super-saturated Al(OH)4- solution near the electrode surface. At higher current densities, the formation of the anodic passivation film is caused by both electrochemical reaction and the diffussion-controlled precipitation.
1986, 3(5): 58-63
Abstract:
Five complexes of the lanthanide nitrates with the cryptand (2.2.2) and cryptand(2.2),La(NO3)3·(2.2),Eu(NO3)3·(2.2)·H2O, Yb(NO3)3(2.2)·2H2O,La2 (NO3)6(2.2.2)MeCN·3H2O, Eu2(NO3)6·(2.2.2)·MeCN·3H2O, have been synthesized in acetonitrile.The complexes were characterized by elemental analyses, IR, NMR, DTA, TG, and electrochemical data.
Five complexes of the lanthanide nitrates with the cryptand (2.2.2) and cryptand(2.2),La(NO3)3·(2.2),Eu(NO3)3·(2.2)·H2O, Yb(NO3)3(2.2)·2H2O,La2 (NO3)6(2.2.2)MeCN·3H2O, Eu2(NO3)6·(2.2.2)·MeCN·3H2O, have been synthesized in acetonitrile.The complexes were characterized by elemental analyses, IR, NMR, DTA, TG, and electrochemical data.
1986, 3(5): 64-68
Abstract:
The miscibility and mechanical damping behavior of rubber blends made of chlorinated butyl rubber/copolymer of butadiene and isoprene were studied by using the linear dilatometer and dynamic viscoelastometer. The results showed that chlorinated butyl rubber and butadiene-isoprene copolymer are partially miscible in the blends.The effect of crystal in the copolymers on the mechanical damping behavior of the rubber blend is notable. Some plateau regions have been noted over the temperature range wide as 60℃ for the loss peak of certain rubber blends.
The miscibility and mechanical damping behavior of rubber blends made of chlorinated butyl rubber/copolymer of butadiene and isoprene were studied by using the linear dilatometer and dynamic viscoelastometer. The results showed that chlorinated butyl rubber and butadiene-isoprene copolymer are partially miscible in the blends.The effect of crystal in the copolymers on the mechanical damping behavior of the rubber blend is notable. Some plateau regions have been noted over the temperature range wide as 60℃ for the loss peak of certain rubber blends.
1986, 3(5): 69-74
Abstract:
With the aid of 13C-NMR spectra of liquid polyoutadiene(PB), catalytically synthesized by Co(Nap)2-Al(i-Bu)3 -PhCCl3, some terminal structures of PB Ⅰ-Ⅵ and two branch structures ⅩⅥ and ⅩⅦ have been identified, providing valuable information for chain initiation mechanism. On the basis of branch structure the number average molecular weight of samples was calculated and compared with the result obtained from VPO measurement.The 13C NMR spectra of PB modified by α-olefine reveal that α-ole-fine only modifies the molecular weight of the polymer, it does not copolymerize with butadiene.
With the aid of 13C-NMR spectra of liquid polyoutadiene(PB), catalytically synthesized by Co(Nap)2-Al(i-Bu)3 -PhCCl3, some terminal structures of PB Ⅰ-Ⅵ and two branch structures ⅩⅥ and ⅩⅦ have been identified, providing valuable information for chain initiation mechanism. On the basis of branch structure the number average molecular weight of samples was calculated and compared with the result obtained from VPO measurement.The 13C NMR spectra of PB modified by α-olefine reveal that α-ole-fine only modifies the molecular weight of the polymer, it does not copolymerize with butadiene.
1986, 3(5): 75-78
Abstract:
Some characteristic behaviours of phenol formaldehyde resins containing crown ether groups, PDB-18c6,PDB-24c8 and PB-15c5 towards U (Ⅵ)in inorganic acid medium such as HCl, H2SO4 and H3PO4 have been studied. It was shown that in hydrochloric acid medium the adsorption of U (Ⅵ) differs from that of U(Ⅵ). The difference may be used for separating uranium ions of different valency. Fe3+ ion was found to have inference on the adsorption of U (Ⅵ). The elution efficiency of U (Ⅵ) from the associated crown polymers by HCl decreases with increase of HCl concentration.γ-ray radiation with dosage up to 5×108 rad shown no effect on the stability of the crown-polymers studied.
Some characteristic behaviours of phenol formaldehyde resins containing crown ether groups, PDB-18c6,PDB-24c8 and PB-15c5 towards U (Ⅵ)in inorganic acid medium such as HCl, H2SO4 and H3PO4 have been studied. It was shown that in hydrochloric acid medium the adsorption of U (Ⅵ) differs from that of U(Ⅵ). The difference may be used for separating uranium ions of different valency. Fe3+ ion was found to have inference on the adsorption of U (Ⅵ). The elution efficiency of U (Ⅵ) from the associated crown polymers by HCl decreases with increase of HCl concentration.γ-ray radiation with dosage up to 5×108 rad shown no effect on the stability of the crown-polymers studied.
1986, 3(5): 79-81
Abstract:
Allyl-ended polydimethylsiloxanes (allyl-PDMS)were synthesized via anionic poly merization of octamethylcyclotetrasiloxane (D4), either by using potassium allyl alcoxide as initiator or by adding allyl bromide as chain terminator. The influence of allyl-PDMS on the polymerization of ethylene in Al(C2H5)3-TiCl4-Mg(OC2H5)2 catalyst system was investigated. It was found that the addition of a small amount of allyl-PDMS improved the catalyst activity in the whole polymerization course examined, resulting in an apparent increase of the yield of polyethylene.However, larger amounts of allyl-PDMS added detracted the activity of the catalyst system, and the lower the molecular weight of allyl-PPMS, the stronger the negative effect on the catalyst activity,
Allyl-ended polydimethylsiloxanes (allyl-PDMS)were synthesized via anionic poly merization of octamethylcyclotetrasiloxane (D4), either by using potassium allyl alcoxide as initiator or by adding allyl bromide as chain terminator. The influence of allyl-PDMS on the polymerization of ethylene in Al(C2H5)3-TiCl4-Mg(OC2H5)2 catalyst system was investigated. It was found that the addition of a small amount of allyl-PDMS improved the catalyst activity in the whole polymerization course examined, resulting in an apparent increase of the yield of polyethylene.However, larger amounts of allyl-PDMS added detracted the activity of the catalyst system, and the lower the molecular weight of allyl-PPMS, the stronger the negative effect on the catalyst activity,
1986, 3(5): 82-84
Abstract:
In this paper, the synthesis of three new aryl-pentadienones has been reported.Their ultra-violet and infrared spectra have been preliminarily examined. It is found that a good linear relationship exists between σpo of p-substituted groups and v(UV) or △λ(IR) of the compound Ⅲ.
In this paper, the synthesis of three new aryl-pentadienones has been reported.Their ultra-violet and infrared spectra have been preliminarily examined. It is found that a good linear relationship exists between σpo of p-substituted groups and v(UV) or △λ(IR) of the compound Ⅲ.
1986, 3(5): 85-88
Abstract:
In this paper a method for estimation of average molecular weight of polymer samples by GPC curves was proposed. The results computed with a programme in BASICl anguage by the proposed mathod are in agreement with those obtained on Waters A 208 Model.
In this paper a method for estimation of average molecular weight of polymer samples by GPC curves was proposed. The results computed with a programme in BASICl anguage by the proposed mathod are in agreement with those obtained on Waters A 208 Model.
1986, 3(5): 89-91
Abstract:
A radical electrode of PVC membrane based on an associated substance of quaternary ammonium salt 7402 [CH3(CnH2n+1)3NCl, n=9-11] or 336S [CH3(C8H17)3NCl] and undecylenic acid radical was described. The electrode made of 7402 ammonium salt exhibites a linear response to undecylenic acid anion in alkaline solution with concentration ranging from 1. 2×10-5 to 5. 2×10-1M. Limit of detection is 7.5×10-6 M.The proposed electrode may be used for pharmaceutical analysis.
A radical electrode of PVC membrane based on an associated substance of quaternary ammonium salt 7402 [CH3(CnH2n+1)3NCl, n=9-11] or 336S [CH3(C8H17)3NCl] and undecylenic acid radical was described. The electrode made of 7402 ammonium salt exhibites a linear response to undecylenic acid anion in alkaline solution with concentration ranging from 1. 2×10-5 to 5. 2×10-1M. Limit of detection is 7.5×10-6 M.The proposed electrode may be used for pharmaceutical analysis.
