Isolation of gossypol from hexane-acetone miscellas

Summary 1. The influence of the nature of the alkali on the degree of extraction of gossypol from hexane — acetone miscellas by solutions of NH₄OH, borax, sodium carbonate, and caustic soda has been studied. It has been established that the maximum extraction of gossypol is achieved by using 2% caustic soda solution.2. It is proposed to treat the aqueous layer formed in the decomposition of the sodium gossypolate with sodium chloride, which enables the yield of gossypol to be raised to 90%.3. It has been shown that the concentration of the miscella in order to eliminate acetone does not lower the yield of gossypol on its isolation from caustic soda solution.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 177–180, March–April, 1978.     

Process for the conversion of highly caustic spent sodium borohydride fuel

The presence of caustic soda in the spent sodium borohydride (NaBH₄) fuel in high concentrations creates environmental problems associated with the transportation and the disposal of the fuel, orits recycling into NaBH₄. It is clear that the high level of caustic soda in the spent fuel requires efficient and proper formulation of its industrial recycling applications. The present study regards the conversion process of the caustic soda present in high concentrations in spent NaBH₄ fuels. Properties of the caustic used in NaBH₄ fuel is characterized using a comprehensive technique. A specific application is presented here, which includes the treatment of the spent fuel solution with anhydrous borax (Na₂B₄O₇) at 90?°C for 3?h followed by calcination after the crystallization, resulting in the conversion of this highly caustic spent NaBH₄ fuel into sodium metaborate (NaBO₂), which is an environmentally friendlier and an economically valuable material.     

Structural Changes and Activation of Cellulose by Caustic Soda Solution with Urea

Investigations on the activation of cellulose by mixed solutions of caustic soda and urea are reported. The structural effects of those solutions on various dissolving pulps are studied by ¹³C-CP/MAS-NMR spectroscopy. In a series of steeping lyes, the concentration of NaOH was varied in a range from 0% to 8% and the urea-concentration in a range from 15% to 40% at ambient temperature and −25 °C. Using solely the single NaOH or urea solutions in the concentration ranges given above, no or only minor structural changes were found. In contrast to that, the cellulose I structure was partially or completely destroyed by using the bicomponent solution with urea added to caustic soda. The structural effect of the bicomponent solutions is comparable with the effect of solely caustic soda solutions of approx. 10% to 18% NaOH. However, the ¹³C-CP/MAS-NMR-spectra from the bicomponent pretreated samples indicate a structure different from the usual ordered structures of sodium cellulose I or II, namely a special urea-NaOH-cellulose complex. The results show that for cellulose activation the NaOH concentration of the caustic soda can be remarkably reduced by adding urea. The improved activating effect of an optimized caustic soda solution with added urea was proved to be useful for the synthesis of cellulose carbamate.     

Predicting the Normal Temperature Depression in Boiling of Complex Aqueous Solutions of Nonvolatile Substances

An equation for predicting the normal temperature depression in boiling of complex aqueous solutions of nonvolatile substances is considered. The constants of the equation are tabulated. The equation is compared with experimental data for a binary solution of caustic soda and sodium chloride.     

Solubilisation von Anthracen in wäßrigen Lösungen von Natriumdodecylsulfat

Summary A colloidal solution of cobalt tungstate of negative charge and highly lyophilic character was prepared by mixing sodium tungstate and cobalt chloride solutions in presence of glycerine and caustic soda. The sol exhibits protective action against the electrolytic coagulation of hydrophobic sols of opposite electrical character. In its coagulation both the anions and cations follow theHofmeister series. The sol is highly viscous and exhibits the acclimatisation effect and also the ionic antagonism.     

草浆造纸黑液中胶体成分的测定方法及其对黑液碱回收的影响

根据草浆造纸黑液组成的特殊性，研究了草浆黑液中液体成分的测定方法，进行了样品分析和回收率试验．取得了较满意的结果。在些基础上讨论了草浆黑液中胶体成分对于黑液碱回收过程的影响。     

Triblock and Radial Star-Block Copolymers Comprised of Poly(ethoxyethyl glycidyl ether), Polyglycidol,Poly(propylene oxide) and Polystyrene Obtained by Anionic Polymerization Initiated by Cs Initiators

The anionic polymerization of ethoxyethyl glycidyl ether (EEGE) initiated by cesium alkoxide was studied. The ring-opening polymerization of EEGE in the presence of cesium alkoxide of 1-methoxy-2-ethanol does not involve any side reactions. The presence of an additional alcohol leads to a significant increase of the initiator efficiency. Aqueous solutions of poly (ethoxyethyl glycidyl ether) (PEEGE) exhibit lower critical solution temperature (LCST), and the polymer solubility in water is extremely sensitive to its MW. Two novel types of block copolymers based on PEEGE were synthesized: triblock-copolymers of ABA (A′:BA′) structure, where A is the PEEGE block, A′ polyglycidol (PG) and B the polypropylene oxide (PPO) block, and A₂S (A′₂S) and A₄S (A′₄S) heteroarm stars, where S is the polystyrene block. The synthesis of the ABA block was performed by polymerization of EEGE initiated by bi-functional PPO/Cesium alkoxide macroinitiator. The PEEGE blocks were converted into PG blocks by successful cleavage of the ethoxyethyl group. Polystyrene/PEEGE and polystyrene/PG three- and five- heteroarm star copolymers were synthesized by a coupling reaction between well-defined chain-end-functionalized polystyrenes carying dendritic benzyl bromide moieties with living anionic polymers of PEEGE with one cesium alkoxide terminal group. The coupling reaction proceeds quantitatively without any side reactions, and thus series of star-branched polymers can be systematically synthesized. Polystyrenes with two or four PG arms have been obtained after the cleavage of the protecting group. The compact structure of these multi-arm star polymers and their amphiphilic character leads to the formation of nanoparticles in aqueous solution with rather uniform size distribution and a mean diameter of 15 nm.     

Controlled synthesis of fluorescent silica nanoparticles inside microfluidic droplets

We study the droplet-based synthesis of fluorescent silica nanoparticles (50-350 nm size) in a microfluidic chip. Fluorescein-isothiocyanate (FITC) dye is first chemically linked to aminopropyl triethoxysilane (APTES) in ethanol and this reaction product is subsequently mixed with tetraethyl orthosilicate (TEOS) to yield a fluorescent silicon alkoxide precursor solution. The latter reacts with an aqueous ethanol-ammonia hydrolysing mixture inside droplets, forming fluorescent silica nanoparticles. The droplets are obtained by pinching-off side-by-side flowing streams of alkoxide solution/hydrolysing mixture on a microfluidic chip using a Fluorinert oil continuous phase flow. Synthesis in droplets leads to a faster reaction and allows drastically improved nanoparticle size uniformity (down to 3% relative standard deviation for 350 nm size particles) when compared to conventional bulk synthesis methods, thanks to the precise control of reagent concentrations and reaction times offered by the microfluidic format. Incorporating FITC inside silica nanoparticles using our method leads to reduced dye leakage and increases the dye's stability, as evidenced by a reduced photochemical bleaching compared to a pure FITC solution.     

Alkali metal counterion control of enolate protonation stereoselectivity

[reaction: see text] Generation of the lithium salt of the norbornenol shown (M = H) followed by quenching with aqueous NH(4)Cl solution gives predominantly the beta-epimeric ketone 6. Similar production of the potassium alkoxide leads instead to the alpha-epimer (99:1). These results reveal the potential importance of alkali metal counterions as stereocontrol elements.     

离子交换法从APT结晶母液中回收钨酸钠

用弱碱大孔离子交换树脂Ｄ３５４在微酸条件下吸附母液中钨，用１０％的苛性钠进行解吸好可获得浓钨酸钠溶液。该法简单而经济。     

Extraction of Mercaptans from Light Hydrocarbon Mixtures with Aqueous Ammonia

Results of laboratory studies of the extraction of light mercaptans (methyl, ethyl, and propyl mercaptans) from hydrocarbons mixtures with a 25% aqueous solution of ammonia (caustic ammonia) are presented and discussed. It is shown that aqueous ammonia can in principle be used for controlled demercaptanization of light hydrocarbon fractions and liquefied hydrocarbon gases containing hydrogen sulfide and lower mercaptans. The advantage of this demercaptanization method over the conventional processes of alkali treatment is that there is no stage of oxidative catalytic regeneration of a spent alkali and there are no its highly toxic wastes, sulfurousalkaline waste waters. The regeneration of a spent (saturated with sulfurous compounds) aqueous ammonia can be comparatively easily performed by its heating (boiling), which leads to a hydrolytic decomposition of ammonium sulfides and mercaptides to release their constituent gases: hydrogen sulfide, mercaptans, and ammonia. Ammonia is recycled into the process as freshly prepared (regenerated) caustic ammonia.

     

Synthesis of N-acyl- and N-aroyl-2-oxazolidones

The action on -chloroethyl N-alkylcarbamates of salts of xanthic and dithiocarbamic acids or caustic soda has given good yields of the otherwise difficult to obtain N-acyl-2-oxazolidones.     

苛性碱、碳酸碱和全碱的同时流动注射分析

采用流动注射滴定技术实现了氧化铝生产过程中铝酸钠溶液中苛性碱、碳酸碱和全碱的同时自动分析。以磺基水杨酸为载流,它既为滴定剂又是铝的掩蔽剂;酚酞和甲基橙混合液为试剂流,它们是苛性碱、碳酸碱和全碱的指示剂。该法可测定６．２～３０．９ｇ／Ｌ的碳酸碱和３．１～１５．５ｇＬ的苛性碱（均以Ｎａ２Ｏ计）,测定速率３０个样／ｈ,标准标准偏差小于０．５％（ｎ＝１１,Ｎａ２Ｏ＝２１．９４ｇ／Ｌ）。     

Effects of nitren extraction on a dissolving pulp and influence on cellulose dissolution in NaOH–water

A commercial dissolving pulp was treated with aqueous solutions containing 3, 5 and 7 % of an organometalic complex (nitren) with the aim to selectively extract xylan and study its impact on the conventional physical–chemical properties of the pulp. The influence of these treatments on the pulp dissolution in a moderate solvent (8 % NaOH aqueous solution) was assessed by measuring the dissolution yields and the dissolution mechanisms. The results of this study show that nitren treatment has the effect of removing a large part of the xylan present in a dissolving pulp. It is also removing mannans and most important, it is influencing cellulose in two ways, (1) extracting it with more intensity when the nitren concentration increases, and (2) decreasing its mean molecular mass, also more evident with nitren concentration increase. The nitren extractions are favourable for the dissolution in cold NaOH–water, being more effective with higher concentrations. This chemical modification of the fiber surface leads to the disassembly of the primary wall. This allows an easier access of the NaOH reagent to regions not accessible on the initial fibres, which with the decrease of the cellulose molecular weight allows an easier dissolution and gives different dissolution mechanisms.     

Effect of chemical reagents on the fine structure of cellulose. Part IV. Action of caustic soda on the fine structure of cotton and ramie

An x-ray study has been made of the changes in lateral order that take place on the treatment of cotton and ramie with different concentrations of caustic soda at 0 and 20°C. When mercerization conditions are reached it is found that there is an increase in lateral disorder in the fibrils. The x-ray diagrams from samples treated in the higher concentrations of caustic soda reveal a residual diffraction effect that can be interpreted in terms of a special type of cellulose sheet. This result implies one extreme of lateral disorder that is present in the fine structure of these materials. Indication is given how these lateral disorder phenomena can affect reactivity.     

The influence of lignin on the self-assembly behaviour of xylan rich fractions from birch (Betula pendula)

A crude xylan isolate obtained by prehydrolysis and mild alkaline extraction from birch wood chips (Betula pendula), and a carefully delignified xylan fraction from the same source, were examined by dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM) with regard to their propensity to self-assemble in water into insoluble aggregates. The delignification involved the extraction with chloroform of a crude xylan solution in a pyridine/acetic acid/water mixture. It resulted in a purified xylan fraction in a yield of 23% in which 75 and 90% of the lignin had been removed as indicated by Klason and UV-determination, respectively. It was found that both xylan fractions formed agglomerates by self-assembly in water. However, DLS and cryo-TEM indicated that the aggregates were larger in size (90 vs. 40 nm) and greater in mass when more lignin was present. The addition of an alkaline solution of isolated lignin (obtained by steam explosion) to increasing concentrations of a delignified xylan revealed increasing turbidity. Our conclusion is that lignin induces agglomeration of xylan in aqueous solutions, but xylan concentration plays an active role in the aggregation phenomena. An agglomeration mechanism for lignin rich xylan fractions is proposed.     

Adsorption and viscoelastic properties of cationic xylan on cellulose film using QCM-D

The adsorption and viscoelastic properties of cationic xylan layers adsorbed from an aqueous electrolyte solution (NaCl 0, 1, 10, 100 mM) on a cellulose model surface were studied using quartz crystal microbalance with dissipation (QCM-D). Three cationic xylans with different charge densities were used (molecular weight, 9,600 g/mol with degrees of substitution, DS = 0.150, 0.191, and 0.259). The influences of the electrolyte concentration and charge density of cationic xylan on its adsorption onto a cellulose surface were investigated. Low charged cationic xylan was substantially more efficient in surface adsorption on cellulose compared to high charged cationic xylan at a low concentration of electrolytes. Adsorption of low charged cationic xylan decreased with increases in electrolyte concentration. However, adsorption of high cationic xylan increased with electrolyte concentration. The conformation and viscoelastic properties of the layers were interpreted by modeling the data under the assumption that the layers can be explained by the a Voigt model. Low charged cationic xylan adsorbed relatively weakly onto the cellulose surface, and formed a thicker, softer layer than high charged cationic xylan. On the other hand, high charged cationic xylan formed a thinner adsorption layer onto the cellulose surface.     

An investigation of the transformations of 2-amino-2-thiazolin-4-one and its derivatives in aqueous solutions

It has been shown by thin-layer radiochromatography that the action of an aqueous solution of alkali on 2-amino-2-thiazolin-4-one and its 5-alkyl derivatives leads predominantly to the opening of the ring by a mechanism similar to the opening of lactams in an alkaline medium.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 44–47, January 1984.     

Syntheses in the pyridine series

It has been shown that when they are heated in 2 N caustic soda solution alkyl pyrid-2-yl sulfides are hydrolyzed at the Py-S bond with the formation of pyridones and the corresponding thiols. The latter were determined quantitatively by iodometric titration.For part VIII, see [1].     

Ion-exchange properties of ammoniated lignin

The oxidative ammonolysis of hydrolysis lignin from sunflower husks has given ion-exchange materials with amphoteric properties. The greatest total exchange capacity of the sample with respect to 0.1 N caustic soda solution amounted to 11.5 meq/g, and with respect to 0.1 N hydrochloric acid solution to 0.6 meq/g. The processes of ion exchange with heavy-metal cations are accompanied by complex formation. The bond of the metal cations with the lignin in the complexes is effected through nitrogen and the oxygen of a nonalcoholic group.