Addition Of Sulfuric Acid Research Articles

Control of Cynthiana Wine Attributes Using Ion Exchange on Different Prefermentation Treatments

Cynthiana (<i>Vitis aestivalis</i>) is a vigorous grape variety that produces a deep-colored and full-bodied red wine. Wine produced from Cynthiana grapes can have both high pH (3.5 to 3.9) and high titratable acidity (8.5 to 12 g/L tartaric acid). Since Cynthiana grapes are used to produce premium wine, different prefermentation treatments (control, ion exchange, tartaric acid addition, sulfuric acid addition) were used in conjunction with ion-exchange systems (no treatment, membrane, resin) to adjust the pH. Although pH was reduced using the different prefermentation treatments, ion exchange of the wine was necessary to lower the pH to an optimum range. Wine pH was lowered from 3.98 to 3.44 using ion exchange in combination with prefermentation treatments. Color and phenolic parameters were measured spectrophotometrically. Ion exchange increased the color density in all prefermentation treatments. Phenolics and red pigment color were not greatly affected by ion exchange and prefermentation treatments. These prefermentation treatments and ion-exchange applications have commercial potential.

A Convenient Synthesis of 4(5)-Alkylacyl-1H-imidazoles from 4(5)-Imidazolecarboxaldehyde

A convenient synthesis of 4(5)-acyl-1H-imidazoles from 4(5)-imidazolecarboxaldehyde without N-protecting group is described. 4(5)-Cyanoimidazole could be synthesized from commercially available 4(5)-imidazolecarboxaldehyde in one-pot. Treatment of 4(5)-cyanoimidazole with various alkylmagnesium bromides followed by addition of aqueous sulfuric acid afforded 4(5)-acyl-1H-imidazoles in good yield.

Efficient Oxidative Aromatization of 9,10-Dihydroanthracenes with Molecular Oxygen Catalyzed by Ruthenium Porphyrin Complex

In the presence of a catalytic amount of a ruthenium porphyrin complex, various 9,10-dihydroanthracene derivatives were aromatized with molecular oxygen to the corresponding anthracenes. It was found that the addition of sulfuric acid accelerated the aromatization at room temperature under atmospheric pressure of oxygen to afford various anthracenes in high yields.

Indirect determination of alkaline phosphatase based on the amperometric detection of indigo carmine at a screen-printed electrode in a flow system.

Amperometric analysis of indigo carmine at a bare screen-printed electrode placed in an FIA system is reported. This compound is easily detected at a potential of -0.3 V (vs. Ag pseudo-reference electrode) without observing any fouling of the electrode surface, thus allowing the repetitive use of the same electrode in a reproducible manner (coefficients of variation down to 7% for more than 20 consecutive determinations). A linear range of three orders of magnitude and a limit of detection in the sub-micromolar range were attained for this molecule. Based on these studies, indirect amperometric measurements of alkaline phosphatase (ALP) activity in solution were easily carried out using 3-indoxyl phosphate substrate. Its hydrolysis catalyzed by ALP gave rise to indigo product. This product is insoluble in aqueous solutions but it was easily converted into its soluble parent compound, indigo carmine, by addition of fuming sulfuric acid to the reaction media. Using this approach, we achieved a linear range of more than one order of magnitude and a limit of detection of 1 U/l ALP, for an enzymatic reaction time of 60 min.

次亜リン酸ニッケルを使用した無電解ニッケルめっき浴のリサイクルシステム

We investigated a recycling process for electroless nickel plating bath using nickel hypophosphite. Phosphite ion accumulated in aged bath were separated as calcium phosphite precipitated by addition of calcium hydroxide, then pH of the phosphite ion separated mother liquor was adjusted to plating condition by way of electrodialysis (method I), which was compared with sulfuric acid addition (method II).The deposition rate kept constant till 30 MTO in method I, but decreased slightly in method II. The internal stress of deposit tended to be almost 0 constantly in method I, but shifted strongly to the tensile side in method II. In addition, concentration of ingredients in the bath remained almost constant in method I, but sulfuric ion concentration increased by accumulation of sulfuric acid added to adjust pH in method II. We found that method I was superior on the pH adjustment to method II from standpoint of keeping bath life long. Corrosion-resistance of film plated by recycled bath remained good (larger than 9 of rating score in a salt spray test) and the surface of the films stayed clean till 30 MTO.We found that there was little variation of the recycling bath composition by the treatment in this condition and constant aging state of the bath was maintained and good plating film was obtained.

Aqueous-phase hydrogenation of lactic acid to propylene glycol

The metal-catalyzed hydrogenation of lactic acid to propylene glycol (PG) in aqueous solution is investigated in a laboratory-scale stirred batch reactor. Ruthenium on activated carbon is identified as an active catalyst for the reaction, with nearly complete conversion achieved at reaction temperatures of 100–170°C and hydrogen pressures of 7–14 MPa. Selectivity to PG in excess of 90% at 95% lactic acid conversion has been obtained at optimal reaction conditions. Potassium and calcium lactate salts cannot be directly converted to PG, but simple addition of sulfuric acid suffices to convert the salt to free acid, which is then hydrogenated. The ready availability of low-cost lactic acid, produced via fermentation of corn-derived carbohydrates, makes this biomass-based route an attractive alternative to the traditional petroleum-based pathways to PG.

Effects of Low pH on Upstream Migratory Behavior in Land-Locked Sockeye Salmon Oncorhynchus nerka

The effects of low pH on upstream migratory behavior in land-locked sockeye salmon Oncorhynchus nerka were examined using 2-way flow-through channels. Homing mature salmon captured at the mouth of their native stream were used. When neutral (pH 6.7) hatchery water of the same origin as native stream water was allowed to flow through both channels, fish showed active swimming into both channels during a 48 hrs period. When water pH in one channel was lowered by the addition of sulfuric acid, salmon completely ceased upstream swimming behavior into areas of pH lower than 6.0, and swam up into only neutral areas. In the lower pond of the 2-way channels, fish also avoided acidic areas even when average pH was 6.2. Since it has been reported that extremely slight changes in pH such as in the pH 6 range inhibits spawning behavior in this species, it is suggested that land-locked sockeye salmon have a sensitive ability to perceive even slight acidity, and avoid environments which may be deleterious to their offspring.

High-yield Carbonization of Cellulose by Sulfuric Acid Impregnation

The carbonization of cellulose with sulfuric acid impregnation was studied by thermogravimetric analysis and scanning electron microscopy. The mass yield of carbon after 800°C treatment in nitrogen increased to 2–3 times by addition of small amounts of sulfuric acid. The sulfuric acid is considered to work as dehydration catalyst, thus suppressing the release of volatile organic substances. The shrinkage of the sample during carbonization was also significantly reduced by the addition of sulfuric acid.

Extraction of Tungsten with Trialkylamine - Effect of pH

Extraction equilibrium in the system aqueous solution of sodium tungstate-solution of trialkylamine in a mixed diluent was investigated. A tertiary amine with C7-C9 straight alkyl chains was dissolved in a mixture of tributyl phosphate and kerosene and presaturated with sulfuric acid to give normal trialkylamine sulfate. Extraction isotherms at 25 °C and at several constant values of equilibrium pH were measured in a broad range of aqueous tungstate concentrations. pH 2.0-6.0 was adjusted by addition of sulfuric acid during equilibration. The equilibrium tungstate and sulfate contents in both phases were determined. A typical tungstate isotherm exhibits a steep ascending part in the low concentration range, corresponding to the region of anion exchange, and a flat part in the high concentration range, where the acid content in the organic phase is virtually exhausted. The level of the flat part decreases with growing pH, corresponding to the increasing number of negative charges per tungsten atom in the tungstate polyanions extracted. At pH &gt; 5, also the effect of hydrolysis of amine sulfate could be detected.

The stability of non-ionic surfactants and linear alkylbenzene sulfonates in a water matrix and on solid-phase extraction cartridges.

The stability of nonylphenol ethoxylates (NPEO), alcohol ethoxylates (AEO), coconut diethanol amides (CDEA) and linear alkylbenzene sulfonates (LAS) in a water matrix and preconcentrated on SPE cartridges was studied. A stability study was carried out in a water matrix (spiked ground water and real-world waste water) comparing different pretreatment procedures (addition of sulfuric acid to pH = 3, preservation with 1% and 3% of formaldehyde). When stored in a water matrix serious qualitative and quantitative changes occurred in waste water during the period of time studied (30 days). The losses of C12-C14 alcohol ethoxylates ranged from 72% to 88% when the sample was preserved with acid and from 17% to 86% when the sample was preserved with formaldehyde (3%). Simultaneously, an enrichment of the shorter alkyl chain homologues (C7EO and C10EO) was observed. The losses of NPEO were from 45% (sample preserved by acidification or by addition of 3% of formaldehyde) to 85% (sample preserved with 1% of formaldehyde). Additionally, an increase in concentration of polyethylene glycols (PEGs) and formation of different acidic forms, such as monocarboxylated (MCPEGs) and dicarboxylated polyethylene glycols (DCPEGs) were observed. The stability of surfactants preconcentrated on SPE cartridges was studied as a function of storage time and storage conditions (room temperature, 4 degrees C and -20 degrees C). The results indicate that disposable SPE cartridges can be recommended for the stabilization of non-ionic surfactants and LAS. Storage at -20 degrees C is feasible for long periods (up to 3 months for ground water and up to 2 months for waste water), while storage at 4 C can be recommended for a maximum of 1 month. When cartridges were kept at -20 degrees C the losses of AEOs (n = 12, 13 and 14), preconcentrated from waste water, ranged from 17 to 29% (after 60 days) and other compounds suffered small losses (maximum of 14% for C13LAS). At room temperature, after 7 days, the losses were less than 11%, indicating that shipping of samples by mail can be done without any special requirements.

Fractionation of unsubstituted cellulose from solutions in either Ni-tren or (N,N-dimethylacetamide + LiCl)

Starting from solutions of unsubstituted cellulose (Avicel PH101, Mw = 30.1 kg/mol and Mw/Mn = 3 or Solucell 500, Mw = 230 kg/mol, Mw/Mn = 2.8) in either Ni-tren (0.8 M aqueous solution of the dihydroxotris(2-aminoethly)amine nickel(II) complex) or in a mixed solvent DMAc+LiCl (consisting of N,N-dimethylacetamide plus lithium chloride) it was investigated whether the segregation of a second phase caused by the addition of suitable precipitants leads to polymer fractionation. With Ni-tren the long chains accumulate in the precipitate formed upon the addition of sulfuric acid; as the pH falls below ≈ 9, the solution is free of cellulose. Nevertheless this route option for fractionation must be ruled out because of a pronounced chain scission taking place in that solvent. For (DMAc + LiCl) the best low molecular weight precipitant that could be found was acetone; it allows the fractionation of the lower molecular weight Avicel but fails for Solucell as a result of the high viscosities of its solutions in the presence of acetone. It was therefore investigated whether that deficiency could be overcome by the use of high molecular precipitants. In these experiments poly-(methyl methacrylate), incompatible with cellulose, was used to cause phase separation. The results demonstrate the suitability of this system for discontinuous experiments even in the case of the higher molecular weight Solucell.

Fractionation of unsubstituted cellulose from solutions in either Ni-tren or (N,N-dimethylacetamide + LiCl)

Starting from solutions of unsubstituted cellulose (Avicel PH101, Mw = 30.1 kg/mol and Mw/Mn = 3 or Solucell 500, Mw = 230 kg/mol, Mw/Mn = 2.8) in either Ni-tren (0.8 M aqueous solution of the dihydroxotris(2-aminoethly)amine nickel(II) complex) or in a mixed solvent DMAc+LiCl (consisting of N,N-dimethylacetamide plus lithium chloride) it was investigated whether the segregation of a second phase caused by the addition of suitable precipitants leads to polymer fractionation. With Ni-tren the long chains accumulate in the precipitate formed upon the addition of sulfuric acid; as the pH falls below ≈ 9, the solution is free of cellulose. Nevertheless this route option for fractionation must be ruled out because of a pronounced chain scission taking place in that solvent. For (DMAc + LiCl) the best low molecular weight precipitant that could be found was acetone; it allows the fractionation of the lower molecular weight Avicel but fails for Solucell as a result of the high viscosities of its solutions in the presence of acetone. It was therefore investigated whether that deficiency could be overcome by the use of high molecular precipitants. In these experiments poly-(methyl methacrylate), incompatible with cellulose, was used to cause phase separation. The results demonstrate the suitability of this system for discontinuous experiments even in the case of the higher molecular weight Solucell.

Rapid reductive dechlorination of atrazine by zero-valent iron under acidic conditions

The dechlorination of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) via reaction with metallic iron under low-oxygen conditions was studied using reaction mixture pH values of 2.0, 3.0, and 3.8. The pH control was achieved through addition of sulfuric acid throughout the duration of the reaction. The lower the pH of the reaction mixture, the faster the degradation of atrazine. The surface area of the sulfuric acid-treated iron particles was 0.31 (±0.01) m 2 g −1 and the surface area normalized initial pseudo-first order rate constants ( k SA, where rate= k SA×(surface area/l)×[Atrazine]) at pH values of 2.0, 3.0, and 3.8 were equal to, respectively, 3.0 (±0.4)×10 −3 min −1 m −2 l, 5 (±3)×10 −4 min −1 m −2 l, and 1 (±1)×10 −4 min −1 m −2 l. The observed products of the degradation reaction were dechlorinated atrazine (2-ethylamino-4-isopropylamino-1,3,5-triazine) and possibly hydroxyatrazine (2-ethylamino-4-isopropylamino-6-hydroxy- s-triazine). Triazine ring protonation may account, at least in part, for the observed effect of pH on atrazine dechlorination via metallic iron.

Preparation and Spherical Agglomeration of Crystalline Cerium(IV) Oxide Nanoparticles by Thermal Hydrolysis

Crystalline cerium(IV) oxide nanoparticles with a cubic fluorite structure could be synthesized from cerium(IV) ammonium nitrate solutions with a relatively high concentration of cerium(IV) (such as 0.5 mol/dm3) via thermal hydrolysis at 150°–240°C. The effects of the treatment temperature, the salt concentration, and the addition of sulfate ions on the crystallite size and morphology of the synthesized particles were investigated. The crystalline nanoparticles had a tendency to agglomerate and form spherical secondary particles with the addition of either ammonium sulfate or sulfuric acid. The existence of sulfate ions in the acidified solution was confirmed to be a factor of consequence for spherical agglomeration of the nanoparticles.

Composting Short Paper Fiber with Broiler Litter and Additives: Part I: Effects of Initial pH and Carbon/Nitrogen Ratio On Ammonia Emission

Short paper fiber (SPF), a by-product of the paper mill industry, was cocomposted with broiler litter (BL) to determine decomposition rate and NH3-N loss as functions of C/N ratio and pH of the compost mixes. The SPF generally had a high C/N ratio >200 while the BL, consisting of bedding material (sawdust) and poultry manure, had a low C/N ratio of 10–12. A total of seven series (27 tests) of pilot-scale studies were conducted using two different SPFs mixed with BL. Additives used for pH control were alum (aluminum sulfate), HiClay® Alumina and sulfuric acid. Mixing ratios [SPF/(SPF+BL), kg/kg(dry basis)] used were 0.8 to 0.4. Test conditions were C/N of 17 to 49, pH of 6.6 to 8.3, initial temperatures of −1 to 22°C, composting temperature of 60°C, water content of 50-55% w.b. and remixing two times per week. Composting temperature was controlled using forced ventilation with a high/low fan setting. Composting trials lasted two weeks. Ammonia loss, O2, CO2, compost temperatures and dry solids loss were measured. Evaluations of ammonia emissions versus initial C/N and pH showed: (1) NH3-N loss decreased as initial C/N increased, even above C/N = 38; (2) NH3-N loss decreased rapidly below pH = 7 and increased rapidly for initial pH above 8. Addition of alum and/or sulfuric acid was found to decrease NH3- N loss while HiClay® Alumina had little or no effect. Results on dry solids loss are not presented in this article.

Comparison of the susceptibility of two hardwood species, Mimosa scabrella Benth and Eucalyptus viminalis labill, to steam explosion and enzymatic hydrolysis

Steam explosion of two hardwood species was carried out with and without addition of sulfuric acid (H2SO4 0.5%, p/v) as a pretreatment catalyst. In general, wood chips of Eucalyptus viminalis Labill were shown to be more amenable to pretreatment than chips derived from bolds of Mimosa scabrella Benth (bracatinga). This was apparent from all pretreatment parameters tested including the overall recovery yields of pretreated fractions, carbohydrates (pentoses and hexoses) recovered as water-solubles, yield of dehydration by-products and lignin susceptibility to acid hydrolysis. There was no evidence for complete deacetylation of both wood species during pretreatment and lignin appeared to undergo extensive acid hydrolysis at higher pretreatment severities. Steam treatment at 205ºC for 5 min without addition of an acid catalyst was shown to be uncapable of removing the hemicellulose component from bracatinga chips, as determined by chemical analysis of the steam-treated water-insoluble fractions. Nearly 30% of the hemicellulose (xylan) found in bracatinga remained unhydrolysed after pretreatment, whereas more than 90% of this component could be removed from eucalypt chips under the same pretreatment conditions. Likewise, pretreatment of eucalypt chips resulted in a more extensive solubilization of glucans (cellulose) by acid hydrolysis. Addition of dilute H2SO4 as a pretreatment catalyst generally increased the recovery yield of fermentable sugars in the water-soluble fractions and this effect was more pronounced for the pretreatment of bracatinga chips. Steam-treated substrates produced from bracatinga were also less accessible to enzymatic hydrolysis than those produced from eucalypt chips, regardless of the use of an acid catalyst.

Radiation-induced grafting of methylmethacrylate onto ultrahigh molecular weight polyethylene and its adhesive characteristics.

The surface of ultrahigh molecular weight polyethylene (UHMWPE) was modified by radiation-grafting methylmethacrylate (MMA) in the presence of sulfuric acid and metallic salt to increase bonding strength with polymethylmethacrylate. The effect of the addition of metallic salts and sulfuric acid on the radiation grafting reaction was investigated when MMA was grafted to the irradiated UHMWPE. The adhesive characteristics with the grafting yield were investigated using conventional acrylic bone cement based on poly(methyl methacrylate) [PMMA]. The results showed that the inclusion of an FeSO4 . 7H2O and sulfuric acid in MMA grafting solutions was extremely beneficial and led to a most unusual synergistic effect, while CuSO4 . 5H2O led to a detrimental effect. The tensile bonding strength between UHMWPE and PMMA sheet increased remarkably with an increased grafting yield on UHMWPE surfaces.

Urinary Phenylmercapturic Acid as a Marker of Occupational Exposure to Benzene.

A hand-saving HPLC method to measure urinary phenylmercapturic acid (PMA) was developed which allows about 35 PMA determinations per day. The method involves conversion of pre-PMA to PMA by the addition of sulfuric acid to a urine sample, extraction into an ether-methanol mixture followed by condensation under a nitrogen stream. The condensate was introduced to a ODS-3 column in a HPLC system, and PMA in the column was eluted into a mobile phase of acetonitrile: methanol: perchloric acid: water. The elution of PMA was monitored at 205 nm. One determination will be completed in 40 min. The method was applied to analysis of end-of-shift urine samples from 152 workers exposed up to 210 ppm benzene, 66 workers exposed to a mixture of benzene (up to 116 ppm) and toluene + xylenes (up to 118 ppm), and 131 non-exposed controls of both sexes. A linear regression was established between time-weighted average intensity of exposure to benzene and urinary PMA. From the regression, it was calculated that urinary PMA level will be about 6.4 mg/l after 8-hour exposure to benzene at 100 ppm, and that PMA in urine accounted for about 0.1% of benzene absorbed. No effects of sex, age, and smoking habit of individuals were detected, and the effect of co-exposure to toluene + xylenes at the levels comparable to that of benzene was essentially nil, which indicates an advantage of PMA as a benzene exposure marker over monoto tri-phenolic metabolites or t,t-muconic acid.

Grafting polymerization of styrene onto preirradiated polypropylene fabric

Grafting copolymerization of styrene onto polypropylene fabric has been studied by using a gamma ray preirradiation technique. The polypropylene fabric samples were irradiated in an environment of air and nitrogen gas. The effects of the absorbed dose, styrene concentration in methanol, reaction temperature and reaction time on the degree of grafting were determined. The effects of a polyfunctional monomer and sulphuric acid on the grafting yield were also examined. The samples irradiated in nitrogen gas gave a much higher degree of grafting than those in air. The addition of sulfuric acid and polyfunctional monomer in the grafting solution enhanced greatly the grafting yield.

Generating Water-Soluble Noxious Gases: An Overhead Projector Demonstration

A simple, inexpensive apparatus to generate and collect water-soluble noxious gases as an overhead projector demonstration can be made from two small beakers and a Petri dish. The detection and generation of sulfur dioxide and nitrogen dioxide are described. Sulfur dioxide dissolved in water is detected using an acid-base indicator, decolorizing of anthocyanin, or reduction of permanganate. The SO2 is generated by addition of sulfite or bisulfite to a strong acid or by the addition of concentrated sulfuric acid to sugars. Nitrogen dioxide is generated by mixing copper and nitric acid and detected using an acid-base indicator.