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A solvent-free, green and efficient mechanochemical method for the synthesis of a series of bridged bicyclo aza-sulfone derivatives viz. 7-oxa-4-thia-1-aza-bicyclo[3.2.1]octane-4,4-dioxides via tandem Michael addition-1,3-dipolar cycloaddition of aldoximes was developed. Mechanochemical grinding/milling facilitates quick formation of aldoximes from corresponding aldehydes and hydroxylamine which upon reaction with divinyl sulfone in a mixer-mill affords 7-oxa-4-thia-1-aza-bicyclo[3.2.1]octane-4,4-dioxide derivatives in good overall yields. The newly synthesized bicyclo aza-sulfone derivatives (4) were screened for antibacterial activities. It was found that mostly bicyclo aza-sulfones derived from electron rich aromatic aldehydes inhibit the growth of Mycobacterium smegmatis (mc2-155) and that of aliphatic aldehydes inhibit the growth of Escherichia coli (DH5a) in moderate to good effect. However, butyraldehyde derived compound 4r was found to be very effective against both M. smegmatis and E. coli. The key advantages of this mechanochemical method are catalyst- and solvent-free condition, shorter reaction time, and the new series of 7-oxa-4-thia-1-aza-bicyclo[3.2.1]octane-4,4-dioxide derivatives are good antibacterial agents against M. smegmatis and E. coli.

The gas-phase kinetics and mechanism of the homogeneous elimination of CO from butyraldehyde in the presence of HCl has been experimentally studied. The reaction is homogeneous and follows the second-order kinetics with the following rate expression: log k1 (s−1 L mol−1) = (13.27 ± 0.36) – (173.2 ± 4.4) kJ mol−1(2.303RT)−1. Experimental data suggested a concerted four-membered cyclic transition state type of mechanism. The first and rate-determining step occurs through a four-membered cyclic transition state to produce propane and formyl chloride. The formyl chloride intermediate rapidly decomposes to CO and HCl gases.

An environmentally friendly method for the trace analysis of four aliphatic aldehydes as water disinfection byproducts has been developed based on hollow-fiber liquid-phase microextraction followed by miniature capillary electrophoresis with amperometric detection. After derivatization with 2-thiobarbituric acid, four aliphatic aldehydes (formaldehyde, acetaldehyde, propylaldehyde, and butyraldehyde) became detectable by the amperometric detector. Under the optimum conditions, four aliphatic aldehydes can be well separated from the coexisting interferents as well as their homologs (pentanal, glyoxal, and methyl-glyoxal), and the limits of detection (S/N = 3) could reach sub-nanogram-per-milliliter level based on hollow-fiber liquid-phase microextraction. The proposed method has been applied for the analyses of above four aliphatic aldehydes in different water samples such as drinking water, tap water, and river water, and the average recoveries were in the range of 90-113%, providing an alternative to conventional and microchip capillary electrophoresis approaches.

To model a biphasic stirred tank reactor, intrinsic reaction kinetics and interfacial area are required. In this study, reactor modeling for n-butyraldehyde aldol condensation was investigated under industrially relevent conditions. The interfacial area in the reactor was directly measured using a borescope system under appropriate temperature, NaOH concentration and rpm conditions. To estimate the interfacial area, a semiempirical correlation was developed, which provides good estimates within ±15% error. The reactor model based on two-film theory was developed, combining the interfacial area and intrinsic reaction kinetics reported in our prior work. The model was verified by reaction experiments in the range 0.05–1.9 M NaOH, 80–130°C, and 600–1000 rpm. The prediction errors using the interfacial area from direct measurements and the correlation were ±8% and ±15%, respectively, suggesting that the model accuracy may be improved with better interfacial area estimation. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2228–2239, 2015

Here we have characterized the first transketolase (TK) from a thermophilic microorganism, Geobacillus stearothermophilus, which was expressed from a synthetic gene in Escherichia coli. The G. stearothermophilus TK (mTKgst) retained 100% activity for one week at 50 °C and for 3 days at 65 °C, and has an optimum temperature range around 60–70 °C, which will be useful for preparative applications and for future biocatalyst development. The thermostability of the mTKgst allowed us to carry out an easy, one-step purification by heat shock treatment of crude cell extracts at 65 °C for 45 min, directly yielding 132 mg of pure mTKgst from 1 L of culture. The reaction rate of mTKgst with glycolaldehyde was 14 times higher at 70 °C than at 20 °C, and 4 times higher at 50 °C when compared to E. coli TK under identical conditions. When tested at 50 °C with other aldehydes as acceptors, mTKgst activity was approximately 3 times higher than those obtained at 20 °C. Applications of this new TK in biocatalysis were performed with hydroxypyruvate as donor and three different aldehydes as acceptors – glycolaldehyde, D-glyceraldehyde and butyraldehyde – from which the corresponding products L-erythrulose 1, D-xylulose 2 and 1,3-dihydroxyhexan-2-one 3 were obtained, respectively. The optical rotations for products 1 and 2 indicate that the stereospecificity of mTKgst is identical to that of other TK sources, leading to a (3S) configuration. With the non-hydroxylated substrate, butanal, the ee value was 85% (3S), showing higher enantioselectivity than the E. coli TK (75% ee, 3S). Processes at elevated temperatures could offer opportunities to extend the applications of TK biocatalysis, by favoring hydrophobic aldehyde acceptor substrate solubility and tolerance towards non-conventional media.

In this study, the sorptive loss patterns for volatile organic compounds were evaluated by gaseous standards containing 13 compounds (benzene, toluene, styrene, p-xylene, methyl ethyl ketone, methyl isobutyl ketone, isobutyl alcohol, butyl acetate, acetaldehyde, propionaldehyde, butyraldehyde, isovaleraldehyde, and valeraldehyde). The gaseous standards, prepared initially at two contrasting concentration levels (40 and 4000 ppb) in a polyester aluminum bag, were measured after two consecutive transfers into empty bags. It indicates that the percent loss patterns, if assessed for all 13 target compounds, are affected most sensitively by the initial concentration levels of samples to yield 2.62 ± 2.22% (at 40 ppb) and 9.57 ± 6.74% (at 4000 ppb). Moreover, the sorptive loss patterns at high concentration samples (4000 ppb) tend to increase in relation with increasing molecular weight of target compounds, although such pattern disappears in low concentration samples (40 ppb). The observed loss patterns, if evaluated in relation to some key parameters like concentration or compound type, suggest the possibility that the sorptive loss of target compounds in storage media can occur in a predictable manner.

This review provides a technical description of the range of commercial products that can be accessed from n-butanol, with specific emphasis on n-butanol derived from renewable sources (biobutanol). n-Butanol itself and primary derivatives in which the oxygen functionality of the molecule is retained (butyraldehyde and butyric acid) have mainstream applications in the solvent, polymer, fuel oxygenate, and/or specialty chemical markets, while butanol dehydration products (butenes and butadiene) present additional opportunities in the hydrocarbon fuel and synthetic elastomers markets. The volume and value of these markets are noted and specific applications of first- and second-generation n-butanol derivatives are discussed. Selected technologies for the conversion of butenes into other valuable olefins are described and current biobutanol producers and technology providers are identified and profiled. © 2012 Society of Chemical Industry and John Wiley & Sons, Ltd

The decomposition of 1,2,3,4-tetrahydronaphthyl-1-hydroperoxide (α-tetralyl hydroperoxide) in the presence of catalytic amounts of zinc and magnesium stearate has been investigated in chlorobenzene and other solvents. For comparison, α, α-dimethylbenzyl hydroperoxide (α-cumyl hydroperoxide) and tert.butyl hydroperoxide have also been decomposed in the presence of the above catalysts. With zinc stearate, α-tetralyl hydroperoxide predominantly yields phenolic products, the zinc soap apparently acting as a Lewis acid. Hydrogen is also obtained; it is probably generated by interaction of the phenolic aldehyde formed (γ-(ortho-hydroxyphenyl) butyraldehyde) and the hydroperoxide. The zinc stearate shows little effect, however, on the decomposition of α-cumyl and tert.butyl hydroperoxide. Magnesium stearate causes a free-radical chain decomposition of α-tetralyl hydroperoxide (see Part I1 ) yielding mainly tetralone and tetralol. This metal soap also accelerates the decomposition of tert.butyl hydroperoxide and, to a less extent, of cumyl hydroperoxide. The catalytic influence of both magnesium and zinc stearate is markedly affected by the solvents employed.

The synthesis of alkylindoles in the gas phase over an aluminium orthophosphate Kearby type catalyst has been studied. As reactants different carbonyl compounds and phenylhydrazine or aniline have been employed. The conditions of temperature and molar ratio of carbonyl compound/nitrogenous compound have been changed. The best results were reached in the reactions between the lower aldehydes and aniline. Thus, 75% alkylindoles were obtained from propanaldehyde and 62% from butyraldehyde. Also remarkable is the reaction between cyclopentanone and phenylhydrazine because 45% 2,3-trimethyleneindole was obtained.

Phosphate catalytic systems (B-PO4, Al-PO4, Ca-Ni-PO4) were tested in transformation of 1-butanol, pure, and in a mixture typical of acetonobutylic fermentation feed, and compared with γ-Al2O3 dehydration catalyst. The phosphates were characterized by infrared spectroscopy and temperature programmed desorption methods. Various 1-butanol reactions can occur, all engaging acidic and basic sites. B-PO4 has the convenient proportion between those sites to dehydrate pure 1-butanol to butenes, with a good activity and selectivity, like γ-Al2O3. Whereas Ca-Ni-PO4 dehydrogenates selectively 1-butanol into butyraldehyde. With the multicomponent mixture, a drop of catalytic activities is observed for phosphates and γ-Al2O3, due, probably, to the great amount of water in the substrate. B-PO4 dehydration activity is much better in that case than γ-Al2O3 one.

Carbonyl compounds (CC) play an important role in beverage aroma since they may affect flavor of wines, brandies, and beers, among others. For this reason, it is necessary to identify and quantify CC through adequate analytical techniques. This study is a proposal of both developing and optimization of a new analytical methodology that allows investigate C(1)-C(8 )CC in wines simultaneously by quantifying even those ones that are predominantly present in the adduct form hydroxylalkylsulfonic acids (HASA). The HASA dissociation is undertaken by specific alkaline media (pH 11). The developed methodology employed the LC with UV/VIS detection (lambda = 365 nm) technique under gradient elution in the way to reach both free-CC and bound-CC quantification. Results showed that binary gradient system using eluent A (MeOH/ACN/H(2)O 74.5:0.5:25% v/v/v) and eluent B (MeOH) reached the best separation condition of both lower and higher molecular mass CC. This proposed method allowed simultaneous quantification of formaldehyde, acetaldehyde, propanone, furfuraldehyde, butyraldehyde, benzaldehyde, hexanaldehyde, 2-ethyl-hexanaldehyde, E-pent-2-en-1-al, and cyclohexanone--all of them were found in white wine (Moscato Canelli) and red wine (Shiraz) produced in the São Francisco Valley, in the Northeastern Region of Brazil--although this optimized method may probably be suitable for quantification of propionaldehyde, isobutyraldehyde, heptanaldehyde, octanaldehyde, benzaldehyde, and E-hex-2-en-1-al as well. We could not prove if this method is also able to determine the latter CC group since we have not found these substances present in detectable levels in our real samples considered in this study.

1,3-Dipolar cycloadditions of azomethine imines 3a and 3b, available by acid-catalyzed treatment of 3-pyrazolidinone 1 with acetone (2a) and butyraldehyde (2b), respectively, were studied. Reactions of 3a with DMAD (4) afforded a mixture of products 9 and 10a, whilst treatment of 3b with DMAD (4) gave a mixture of compound 9 and epimeric cycloadducts 10/10′b. On the other hand, cycloadducts 13a,b-16a,b were isolated as single diastereomers in 9–37% yields upon reactions of 3a,b with olefinic dipolarophiles 5–8. The structures of cycloadducts 9, 10a, 10/10′b, and 13a,b-16a,b were determined by 1H nmr and NOESY spectroscopy. The structure of compound 13a was confirmed by X-ray diffraction.

The kinetics of absorption of oxygen by n-butyraldehyde dissolved in n-butyric acid, in the range of concentrations up to 3·1 × 10 -3 gmole/cm 3 (25 wt.-%), in the presence of manganese acetate, was studied in stirred cells and a bubble column. It was found that diffusion of oxygen is important. The reaction was found to be first-order in oxygen and second-order with respect to the aldehyde. The overall third-order reaction rate constant was found to be about 4 × 10 6 (cm 3 /gmole) 2 sec -1 at 20°. The effect of the catalysts, cobaltous acetate and (cobaltous + 4 cupric) acetates, on the specific rates of absorption of oxygen was also studied. Manganese acetate was found to be the best catalyst.

Butyraldehyde is an important chemical for many industrial applications, especially in the production of polyvinylbutyral. A systematic study of its synthesis by catalytic dehydrogenation of butanol, using zinc oxide as catalyst has been carried out. The effect of the method of preparation of zinc oxide on its catalytic activity for the title reaction has also been studied. The optimum conditions for maximum yield have been worked out and on the basis of secondary electron micrograms the reasons for higher activity/selectivity in the case of zinc oxide calcined from zinc hydroxide is attributed to the presence of hexagonal morphology. A kinetic study for the best zinc oxide catalyst has been carried out and the rate equation has been determined.

Photocatalysis utilizes near-UV or visible light to break down organic pollutants into innocuous compounds at room temperatures. This paper introduces the use of semiconducting optical crystals as an additive to a photocatalyst. The perovskite optical material BaTiO 3 (band gap of 3.7-3.8 eV) is found to increase VOC destruction when black light is used. The best composition found is 0.1 wt% BaTiO 3 with the balance being TiO 2 . This photocatalyst increases tetrachloroethylene (PCE) conversion by 12% to 32% for space times between 1.4 and 17.2 seconds and inlet concentrations of 40 to 130 ppm with a 4 W black light. The average enhancement is approximately 25 %. For butyraldehyde conversion the maximum enhancement is 20 % at 130 ppm in 3.6 seconds. The UV/VIS spectroscopy data indicate a lower absorbance with the additive. The reaction parameters studied are space velocity, inlet concentration and light source. Oxidation by-products are identified using a GCMS.

The photooxidations of n-butyraldehyde initiated by Cl atom were carried out at room temperature (298 +/- 2K) and 1 atm pressure. The rate coefficient for the reactions of Cl atom with n-butyraidehyde was determined as k = (2.04 +/- 0.36) x 10(-10) cm(3) molecule(-1) s(-1) by using relative rate techniques. The photooxidation products of n-butyraldehyde reaction with Cl atom were also studied by using both gas chromatography-mass spectrometry (GC-MS) and gas chromatography techniques. C2H5CHO, CH3CHO, CO and CO2 were the major products observed. in the absence of NO, the observed yields of C2H5CHO, CH3CHO, and CO were 60%, 3%, and 9%, respectively. However, when NO was introduced into the reaction chamber and the initial ratios of [NO](0)/[n-butyraldehyde](0) were between I and 8, the yield of C2H5CHO decreased to 33%, whereas that of CH3CHO and CO rose up to 21% and 25%, respectively. On the basis of mechanism data deduced in this study and the fraction molar yields, the approximate branching ratios for Cl atom attack at -C(O)H, alpha-, beta-, and gamma-positions in n-butyraldehyde could be derived as >= 42%, < 25%, 21%, and

Tosylhydrazones derived from aliphatic aldehydes or ketones, such as cyclohexanone or butyraldehyde, do not afford the desired trisubstituted alkenes.

The condensation reaction of butyraldehyde (BA) with poly(vinyl alcohol) (PVA) to give poly(vinyl butyral) (PVB) was studied in detail using N-methyl-2-pyrrolidone (NMP) as solvent for PVA and PVBs. PVBs having various degrees of acetalization were obtained. The acetalization reaction under a variety of conditions gave at best a polymer with 97% acetalization. The extent of modification and the structure of the polymer, i.e., the ratio of acetal units from meso and racemic dyads of PVA, were determined by 1H-NMR. The acetalization degree was reflected in the solubility of PVB; all products were soluble in NMP. PVBs were characterized by IR spectroscopy and 1H and 13C-NMR. The glass transition temperatures of PVBs, determined by DSC, increased as vinyl alcohol units increased and displayed a positive departure from linearity. Thermal degradation of PVBs was studied using differential thermal analysis (DTA) and thermogravimetry (TGA) under dynamic conditions in nitrogen. The content of hydroxyl groups had an effect on the thermal stability of PVBs; the thermal stability of PVBs decreased as vinyl alcohol units increased. The apparent activation energy of the decomposition was determined by the Kissinger and Flynn–Wall methods, which agree well. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5007–5017, 2006

The change of the raw material basis to alternative sources, especially biomass, is advisable because of both the continuous shortage of fossile resources and the advancing change in world climate. Carbohydrates have the highest share in biomass. However, as they are overfunctionalized with chemically almost equal hydroxy groups, the high-scale industrial use of carbohydrates is restrained. In addition, the diversity and the high amount of functional groups of carbohydrates complicate the prediction of possible reaction pathways. This is the reason why monoalcohols and polyols are used as model compounds. One interesting reaction is the dehydration of 1,2-butanediol to n-butyraldehyde, an important chemical intermediate. Supercritical water is an appropriate reaction medium for dehydrations because of its special physical and chemical properties. The addition of acids enhances the reaction rate but at the same time intensifies corrosion. Sulfate salts, especially zinc sulfate, can have similar positive effects without increasing the corrosion potential. The experimental results of the catalytic influence of different metal sulfate salts on the dehydration of 1,2-butanediol to n-butyraldehyde are presented in this paper.

The downstream processing of 1,3-propanediol fermentation broth using flocculation, reactive extraction, and reactive distillation was studied. Cellular debris and soluble protein in the broth were flocculated by combined use of chitosan and polyacrylamide at optimal concentrations of 150 ppm and 70 ppm, respectively; the soluble protein in the broth decreased to 0.06 g L−1, and the recovery ratio of the supernatant liquor to broth was greater than 99%. 1,3-Propanediol and other alcohols were extracted from the supernatant liquor by reacting with butyraldehyde. In a four-stage countercurrent extraction with the volume ratio of the extraction solvent to the aqueous phase being 20:100, more than 99% 1,3-propanediol acetal (2-propyl-1,3-dioxane) and 2,3-butanediol acetal (2-propyl-4,5-dimethyl-1,3-dioxolane) were recovered from the aqueous phase; 35% of the glycerol acetals were recovered. The acetals produced were hydrolyzed in a reactive distillation column using the strongly acidic cation-exchange resin as catalyst, the bottom product obtained was a mixture of 1,3-propanediol (407 g L−1), 2,3-butanediol (252 g L−1), glycerol (277 g L−1), and glycerol acetals (146 g L−1). Copyright © 2005 Society of Chemical Industry

Poly(m-xylylene adipamide) (nylon MXD6), D-sorbitol, and a-cyclodextrin aldehyde-scavenging agents were blended with poly(ethylene terephthalate) and thermally pressed into films. Films were stored in an acidified aqueous model solution (pH 3.6) containing a 25 μM mixture of acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, and caproaldehyde for 1, 3, 7, and 14 d. The total amount of aldehydes sorbed by films was 2 to 10 times higher for films containing aldehyde-scavenging agents than nonblended films. Aldehyde-scavenging films demonstrated selective scalping, preferring smaller molecular weight aldehydes to larger aldehydes. Partition coefficients for smaller aldehydes were 3 to 6 times greater for aldehyde-scavenging films than control film.

A new analytical procedure based on electrochromatography was developed for the separation and quantitation of 14 aldehydes and ketones (formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butanone, crotonaldehyde, isobutyraldehyde/butyraldehyde, 2-pentenaldehyde, isovaleraldehyde, valeraldehyde, benzaldehyde and hexanaldehyde) in ambient air currently to be regulated by the Hong Kong Environmental Protection Department. A volatile mobile phase using ammonium acetate compatible with mass spectrometry detection was developed and optimized as follows. Methanol: acetonitrile: aqueous buffer (4 mM ammonium acetate) = 65:5:30% v/v. With electrokinetic injection at 5 kV for 2 s, aqueous buffer pH adjusted to 8, applied voltage controlled at 25 kV, and detection at 360 nm in a fused-silica column packed with 3 microm ODS, a satisfactory separation was obtained for the 14 carbonyl compounds investigated. The working ranges in acetonitrile solution were found to vary from 0.25 to 79 mg/L with a correlation coefficient greater than 0.99, detection limits from 0.10 to 0.63 mg/L, and precision (relative standard deviation, n = 3) from 2.3 to 9.2%. Under an air flow rate of 0.3 L/min for a sampling time of 1 h, the working ranges varied from 0.030 to 11,000 microg/m3 and detection limits from 0.011 to 0.084 microg/ m3. The method has been successfully applied to monitor three carbonyl compounds in four urban and rural sites in Hong Kong and gave hourly readings of three carbonyl compounds for all the sites investigated with a separation time less than 25 min.

Poly(vinyl alcohol) (PVA) can be dissolved in a nonaqueous medium in the presence of catalytic concentration of ethyl nitrate dimethyl sulfoxide, C2H5ONO2 · DMSO (EN · DMSO). From the PVA solution, poly(vinyl butyral) (PVBu) was prepared by acid-catalyzed homogeneous acetalization of PVA with butyraldehyde. The formation of PVBu was confirmed by IR and 1H-NMR spectra. The degree of acetalization of PVBu was found to be 95 mol %, which was verified by 1H-NMR data and acetylation method. The molecular mass of the polymer was determined by GPC method. The glass transition temperature, Tg, was measured from differential scanning calorimetric (DSC) thermograms. Thermal stabilities were checked by thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). The acetal decomposed in three stages. The corresponding initial decomposition temperatures were found to be 285, 390, and above 500°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1182–1186, 2001

Oxygenated compounds such as ethers and alcohols are used as gasoline additives and industrial solvents. However, despite their widespread use, the atmospheric reaction mechanisms of some of these compounds are unknown. This study examines the ·OH-initiated gas-phase removal mechanisms of ethyl-n-butyl ether (ENBE) and di-n-butyl ether (DNBE) utilizing gas chromatography–mass spectrometry techniques. The primary products and molar yields from the hydroxyl-radical–initiated photooxidation of ENBE in the presence of nitric oxide were acetaldehyde (0.173 ± 0.012), ethyl formate (0.219 ± 0.033), butyraldehyde (0.076 ± 0.004), butyl formate (0.241 ± 0.009), butyl acetate (0.032 ± 0.001), and ethyl butyrate (0.0044 ± 0.0006). From the calculated molar yields, approximately 45.5% of the reacted carbon were recovered. The primary products and molar yields from the DNBE and hydroxyl radical reaction in the presence of nitric oxide were propionaldehyde (0.379 ± 0.022), butyraldehyde (0.119 ± 0.003), butyl formate (0.410 ± 0.009), and butyl butyrate (0.019 ± 0.001). Approximately 47.7% of the reacted DNBE were recovered. The chemical mechanisms are presented to explain the formation of these products. In addition, the importance of the isomerization and nitrate/nitrite formation pathways in the reactions of large ethers are discussed. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 328–341, 2001

Vapor-phase aldol condensation of n-butyraldehyde to 2-ethyl-2-hexenal was studied at 1 atm and 150∼ 300°C in a fixed-bed, integral-flow reactor by using NaX, KX, γ-Al2O3 and Na/NaOH/γ-Al2CO3 catalysts. Ion exchange of NaX zeolite with potassium acetate solution results in a decrease of crystallinity and apparent lowering of surface area, whereas the basic strength is enhanced. Treatment of γ-Al2O3 with NaOH and Na causes a large decrease of the surface area but strong enhancement of the catalyst basicity. The catalytic activity on the basis of unit surface area is in the order Na/NaOH/γ-Al2O3 γ-Al2O3, in accordance with the relative catalyst basic strength. The molar ratio of trimeric to dimeric products increases with increasing the reaction temperature and the catalyst basic strength except for Na/NaOH/γ-Al2O3. Very high selectivity of 2-ethyl-2-hexenal (>98.5%) was observed for reactions over NaX zeolite at 150°C. Based on the FT-IR and the catalytic results, the reaction paths are proposed as follows: self-aldol condensation of n-butyraldehyde, followed by dehydration produces 2-ethyl-2-hexenal, which then reacts with n-butyraldehyde and successively dehydrates to 2,4-diethyl-2,4-octadienal and 1,3,5-triethylbenzene. For the reaction over NaX, the calculated Arrhenius frequency factor and activation energy are 314 mol/g·h and 32.6 kJ/mol, respectively.

The simultaneous methanolysis and butryalization of poly(vinyl acetate) was conducted via the reaction of methanol and butyraldehyde with polyvinyl acetate under batch conditions at temperatures from 70°C to 90°C at the vapor pressure of the reactants. It was found that use of an acid catalyst allowed for the methanolysis to be the rate limiting step of a simultaneous methanolysis-butyralization reaction, minimizing the buildup of alcohol repeat units in the polymer during the reaction. As such, use of an excess of aldehyde was counterproductive in that it served to dilute both the methanol and the acetate groups in the polymer phase, lowering the overall rate of the reaction. With 20% stoichiometric excesses of methanol and butyraldehyde, it was possible to produce poly(vinyl butyral) directly from poly(vinyl acetate) with very low residual acetate and overall conversions equivalent to commercial samples. Further, carbon dioxide was evaluated as a reversible plasticizer for polyvinyl acetate during methanolysis. Results at various pressures were consistent with the expectation that the presence of CO 2 would lower the reaction rate, primarily because of dilution of reactants in the CO 2 -swollen polymer phase. Finally, it was shown that the simultaneous reaction procedure can be used to generate polyvinyl acetals from a variety of aldehydes.

Triphenylamine (TPA) was reacted with carbonyl compounds such as formaldehyde, butyraldehyde, benzaldehyde, and acetone in the presence of an acid catalyst. 1 H and 13 C NMR spectra revealed that the carbonyl compounds react only at the p-position of TPA. The reactivity of formaldehyde with TPA is lower than that with phenol. If equal molar amounts of formaldehyde are reacted, however, TPA condensation proceeds to high molecular weight polymers, while phenol provides only low molecular weight compounds (up to 1000). TPA-aldehyde polymers have glass transition temperatures in the range of 135-176°C. These polymers show good solubility and sufficient stability after film formation.

Gas phase hydrogenation of crotonaldehyde to crotyl alcohol, butyraldehyde, and butanol was studied in a differential microreactor at atmospheric pressure and 353 K over a supported Pt catalyst. The reaction rate was seen to be dependent on the catalyst pre-treatment mode. Rapid deactivation has been observed and the deactivation rate differed for differently treated samples. Kinetic modelling was based upon reaction a network, which apart from conventional dehydration steps included parallel hydrogenolysis to hydrocarbons. Deactivation phenomena were assumed to occur as a result of the formation of surface deposits, which block active catalyst sites. An adequate description of experimental data has been achieved via parameter estimation.

A large and potentially hazardous decrease in aldehyde autoignition temperature (AIT) occurs with increased pressure. The AIT-pressure curve determined in a 5 L stainless steel sphere was similar for propionaldehyde and butyraldehyde in air, falling from about 185°C at atmospheric pressure to 90°C at 140 psia. Reduction of oxygen concentration had little effect on propionaldehyde AIT. At 100°C and 140 psia, autoignitions accompanied by at least a doubling of pressure were observed above 4% oxygen. In the presence of a few grams of free liquid, propionaldehyde vapor ignited in air at initial conditions significantly below the AIT. The mechanism appears to involve rapid Fe-catalyzed exothermic liquid-phase oxidation leading to autoignition of the adjacent heated gas layer. An acetaldehyde vapor-air mixture in the presence of free liquid and rust exploded at room temperature when air pressure was increased to 95 psia; this result is discussed with reference to a cylinder overpressurization that occurred while making up an ostensibly sub-LFL calibration mixture with compressed air. Propionaldehyde's limiting oxygen concentration (LOC) was investigated in the near-autoignition region using the same 5L apparatus; the findings are discussed with reference to an overpressurization incident in an air-liquid partial oxidation reactor. The general results are used to illustrate the application of LOC in partial oxidation processes subject to autoignition and to discuss elements of the current ASTM draft test method for LOC, which does not address test difficulties associated with condensable and/or reactive gas systems.

A 3-component Povarov reaction between butyraldehyde, aromatic amines and ethyl vinyl ether in trifluoroethanol followed by an oxidation, offers a convenient entry to differently substituted 2-propylquinolines.

Reactions of n-C4H9O radicals have been investigated in the temperature range 343–503 K in mixtures of O2/N2 at atmospheric pressure. Flow and static experiments have been performed in quartz and Pyrex vessels of different diameters, walls passivated or not towards reactions of radicals, and products were analyzed by GC/MS. The main products formed are butyraldehyde, hydroperoxide C4H8O3 of MW 104, 1-butanol, butyrolactone, and n-propyl hydroperoxide. It is shown that transformation of these RO radicals occurs through two reaction pathways, H shift isomerization (forming C4H8OH radicals) and decomposition. A difference of activation energies ΔE = (7.7 ± 0.1 (σ)) kcal/mol between these reactions and in favor of the H-shift is found, leading to an isomerization rate constant kisom (n-C4H9O) = 1.3 × 1012 exp(− 9,700/RT). Oxidation, producing butyraldehyde, is proposed to occur after isomerization, in parallel with an association reaction of C4H8OH radicals with O2 producing OOC4H8OH radicals which, after further isomerization lead to an hydroperoxide of molecular weight 104 as a main product. Butyraldehyde is mainly formed from the isomerized radical HOCCCC˙ + O2 ··· O (DOUBLE BOND) CCCC + HO2, since (i) the ratio butyraldehyde/(butyraldehyde + isomerization products) = 0.290 ± 0.035 (σ) is independent of oxygen concentration from 448 to 496 K, and (ii) the addition of small quantities of NO has no influence on butyraldehyde formation, but decreases concentration of the hydroperoxides (that of MW 104 and n-propyl hydroperoxide). By measuring the decay of [MW 104] in function of [NO] added (0–22.5 ppm) at 487 K, an estimation of the isomerization rate constant OOC4H8OH HOOC4H7OH, κ5 ≅ 1011exp(−17,600/RT) is made. Implications of these results for atmospheric chemistry and combustion are discussed. © 1996 John Wiley & Sons, Inc.

Non-chelate control is found to be the favored stereochemical outcome in the addition of the 1-bromo-1-lithio-1-alkenes 2b and (S)-5b to O-protected lactaldehydes (S)-1. Thus diastereoselectivities of 84 to 96% d.e. are reached in the formation of alcohols 3 and 6, which are converted into the O-protected 2,3-dihydroxyaldehyde 31 or O-protected 1,2,3-triols 24 and 27. In an analogous way, a non-chelate-controlled addition of (R)-5b to (R)-3-(benzyloxy)butyraldehyde (14a) leads to the predominant formation of the diastereomer 15a (92% d.e. after enrichment by chromatography) which yields the alcohol 42a upon debromination, O-protection, and ozonolysis. Thus, the carbenoids 2b and 5b enable the introduction of the synthons −CH2OH and −CHO into enantiomerically pure aldehydes (S)-1 and (R)-14 in a highly stereoselective manner. Relatively low diastereoselectivities are reached in the „mismatched” combination of (R)-5b with (S)-1 as well as (S)-5b with (R)-14. The dilithium compound 20b, generated at −78°C, reacts in a retro-1,4-Brook rearrangement at −20°C to give vinylsilane 44b after protonation.

In a continuation of work on the synthesis of eightand nine-membered nitrogen-containing heterocycles [1-3] and on the use of the Ugi reaction in the synthesis of benzodiazepine derivatives [4], we decided to develop a new isocyanide multicomponent reaction (MCR) using the reaction which we have discovered for the tandem expansion of heteroannelated tetrahydropyridines and azepines under the influence of activated alkynes. The experimental data we obtained earlier allowed us to suggest with certainty that propiolic acid, in contrast to its esters did not give products of the ring expansion with heteroannelated tetrahydropyridines. We have proposed that if propiolic acid was used as the carboxylic component in the Passerini reaction [5] then the oxoethylpropiolate A formed in situ, being an activated alkyne, might react with heteroannelated tetrahydropyridines introduced in this reaction as a fourth component. As a model experiment, we studied a MCR with tetrahydrothienopyridine 1 [6], butyraldehyde (2), propiolic acid (3), and isonitrile 4. The reaction was carried out at a temperature of -5 to 0°C in an atmosphere of argon. As a result the required thienoazocine 5 was isolated from the reaction mixture in a yield of 32%. Thus, we have found the first example of a multicomponent reaction for the expansion of a tetrahydropyridine ring. Despite the small yield of the required azocine, this reaction may serve as an effective method for the synthesis of difficult to obtain derivatives of medium nitrogen heterocycles. H and C NMR spectra were recorded with a Bruker WP-400 spectrometer (400 and 100 MHz respectively) in CDCl3 solution with TMS as internal standard. The assignment of the signals in the H NMR spectra was based on the data from the H-H COSY experiment. IR spectra of nujol mulls were recorded on an Infralum FT-801 Fourier spectrometer. The LC/MS spectra were obtained with a system which included an Agilent 1100 series liquid chromatograph and an Agilent Technologies LC/MSD VL mass spectrometer (electrospray injection, APCI), ELSD Sedex 75 detector. Butyraldehyde (2), propiolic acid (3), and the isonitrile 4 were commercial products. The aldehyde 2 was distilled at normal pressure under argon before use in the reaction, the other reagents were used without additional purification.

The pentacyclic alkaloids vincadifformine (9), ψ-vincadifformine (15), and epi-ψ-vincadifformine (16) could be synthesized by intramolecular free-radical-induced cyclizations of the tetracyclic intermediates 7, 8, and 18, which were respectively obtained by condensation of the indoloazepine 1 with 2-(phenylselenyl)butyraldehyde and subsequent Nb-alkylation of the resulting tetracyclic amines 2 and 3, or from condensation of (phenylselenyl)acetaldehyde with the alkylated indoloazepine 17. The intermediates 2 and 3 also gave 3-oxovincadifformine (21) by an intermolecular radical alkylation with methyl acrylate. Their alkylation with (Z)-1,3-diiodopropene, phenyl selenoxide elimination, and intramolecular Heck reactions provided tabersonine (24) and 18,19-didehydrotabersonine (27).

Aldol condensation of n-butyraldehyde to produce 2-ethylhexenal in gas-phase over solid catalysts based on niobium, tantalum or tungsten oxide supported on silica was studied. The catalysts were prepared by different procedures based on co-precipitation or impregnation methods and characterized by X-ray fluorescence, scanning electron microscopy and specific surface-area determinations. The self-condensation of n-butyraldehyde in the temperature range 150-350°C, at contact times of 1-8 s, and through a continuous-flow microreactor at atmospheric pressure, was investigated. Supported niobium oxide, either co-precipitated or impregnated, gave better yields than both tantalum and tungsten oxide, with selectivities to 2-ethylhexenal higher than 95% up to 250°C. The performances of the niobium oxide-supported catalyst were also much better than those hitherto stated in the literature for a catalyst based on reduced tin supported on silica gel.

Investigations were carried out of the synthesis of butyronitrile via the ammonolysis of butylalcohol and the dehydrogenation of butylamine over Mo[sub 2]N. At 573 K butyronitrile is produced with virtually 100% yielded by both reactions. The ammonolysis of butylalcohol proceeds via dehydrogenation of the butylalcohol to form butyraldehyde, which then reacts with ammonia to produce butylimine. Butyronitrile is formed by butylimine dehydrogenation. The formation of butyronitrile from butylamine occurs via the stepwise dehydrogenation of the amine. The presence of ammonia in the gas phase suppresses the hydrogenolysis of either butylalcohol or butylamine. 11 refs., 8 figs., 2 tabs.

In situ infrared (IR) technique has been employed to study the reaction of adsorbed CO on Rh/SiO 2 and S-Rh/SiO 2 with C 3 H 6 and H 2 , and to investigate the effect of sulfur on the n - and isobutyraldehyde selectivities during steady-state propylene hydroformylation. CO adsorption on Rh/SiO 2 results in the formation of linear CO and bridged CO adsorbed on Rh 0 sites, and the gem-dicarbonyl on Rh + sites. CO adsorption on S-Rh/SiO 2 results in a high wavenumber Rh + (CO) species in addition to linear CO adsorbed on Rh 0 and the gem-dicarbonyl adsorbed on Rh + . Sulfur decreases the rate of CO adsorption and inhibits the formation of bridged CO on Rh/SiO 2 . Pulse CO chemisorption on Rh/SiO 2 and S-Rh/SiO 2 reveals that the equilibrium constant for CO adsorption on S-Rh/SiO 2 is smaller than that on Rh/SiO 2 at 303 K. Exposure of adsorbed CO to C 3 H 6 at 303 K does not result in the formation of the aldehyde on both Rh/SiO 2 and S-Rh/SiO 2 . Exposure of adsorbed CO to C 3 H 6 and H 2 on Rh/SiO 2 causes a decrease in the intensity of the linear CO band and a slight increase in the intensity of the aldehyde band. A prominent decrease in the Rh + (CO) band is observed on S-Rh/SiO 2 with a simultaneous increase in the aldehyde band on exposure of adsorbed CO to C 3 H 6 and H 2 . The linear CO on Rh + is more active for CO insertion than linear CO on Rh 0 at 303 K. The Rh + (CO) is removed from the surface of S-Rh/SiO 2 at temperatures above 363 K in the presence of C 3 H 6 /H 2 ; however, the species remains stable at 513 K in the absence of H 2 . Sulfided Rh/SiO 2 exhibits a higher CO insertion selectivity, a lower hydrogenation activity, and a lower n-/iso-butyraldehyde selectivity than Rh/SiO 2 during steady-state propylene hydroformylation at 513 K and 0.1-1 MPa. The analogy between homogeneous and heterogeneous hydroformylation suggests that enhancement of the isobutyraldehyde formation by adsorbed sulfur could be due to the spacious environment of the protruding Rh + ion sites on the S-Rh/SiO 2 allowing isomerization of n -propyl groups before CO insertion.

The catalytic properties of various solid bases for self-condensation of n-butyraldehyde in liquid phase were studied to elucidate the factors governing the activity and selectivity. For alkaline earth oxide catalysts and γ-alumina catalyst, aldol condensation occurred, followed by Tishchenko-type cross-esterification of n-butyraldehyde with the dimer produced by the aldol condensation to form trimeric glycol ester. Alkali ion-modified alumina catalysts exhibited a high selectivity for the aldol condensation dimer, the trimeric glycol ester being formed tittle. Both basic and acidic sites on the surfaces of the alkaline earth oxides and γ-alumina were assumed to contribute to Tishchenko-type cross-esterification. The suppression of Tishchenko-type cross-esterification for alkali ion-modified alumina catalysts is due to the absence of acidic sites on the surfaces. The catalytic performances of alumina-supported magnesium oxide and alkali zeolite X were also examined. Alumina-supported magnesium oxide exhibited lower activity but higher selectivity to trimeric glycol ester than MgO. This catalytic feature was caused by the lower basicity and higher acidity on the surface of alumina-supported magnesium oxide as compared with MgO. The activity of alkali ion-exchanged zeolites was lowest among the catalysts examined in this study. The modification of zeolites with excess alkali ions improved the activity.

Non-chelate control is found to be the favored stereochemical outcome in the addition of the 1-bromo-1-lithio-1-alkenes 2b and (S)-5b to O-protected lactaldehydes (S)-1. Thus diastereoselectivities of 84 to 96% d.e. are reached in the formation of alcohols 3 and 6, which are converted into the O-protected 2,3-dihydroxyaldehyde 31 or O-protected 1,2,3-triols 24 and 27. In an analogous way, a non-chelate-controlled addition of (R)-5b to (R)-3-(benzyloxy)butyraldehyde (14a) leads to the predominant formation of the diastereomer 15a (92% d.e. after enrichment by chromatography) which yields the alcohol 42a upon debromination, O-protection, and ozonolysis. Thus, the carbenoids 2b and 5b enable the introduction of the synthons −CH2OH and −CHO into enantiomerically pure aldehydes (S)-1 and (R)-14 in a highly stereoselective manner. Relatively low diastereoselectivities are reached in the „mismatched” combination of (R)-5b with (S)-1 as well as (S)-5b with (R)-14. The dilithium compound 20b, generated at −78°C, reacts in a retro-1,4-Brook rearrangement at −20°C to give vinylsilane 44b after protonation.

Acetaldehyde and butyraldehyde azines and 1,2-bis(tert-butylimino)ethane add only one molecule of dialkyl H-phosphonate at room temperature to form alkyl (α-aminoalkyl)phosphonates. IR spectra of compounds obtained are discussed.

Esters of the dienyl iodide 2a , which was obtained stereoselectively from the corresponding tin derivative 2b , were shown to condense with i -butyraldehyde in the conditions of the Kishi-Nozaki-Takai reaction without alteration of the E , E configuration of the butadiene moiety.

A new acid-catalyzed method for the synthesis of (Z)-3-butylidenephthalides 5 and a novel and general route to 3-alkyl-8-hydroxy/methoxyisocoumarins 6-8 from phthalides 9 is described. The hydroxyphthalides 4 and 10 were obtained by condensation of the phthalide anion with butyraldehyde and acetaldehyde. Reaction of hydroxyphthalides 4 with a mixture of orthophosphoric acid and formic acid gave the (Z)-3-butylidenephthalides 5, while the hydroxyphthalides 4 and 10 on reaction with p-toluenesulfonic acid provided the 3-alkylisocoumarins 6-8. The present approaches permit variation of the 3-substituent in isocoumarin and the pattern of functionalization on the aromatic rings of both isocoumarins and alkylidenephthalides.

Oxidation of cycloalkenes with O 2 promoted by heterogeneous bis(acetylacetonato) cobalt (II) complex catalyst which can be recycled has been performed under mild conditions. It was found that β-ionone, cyclohexene, 1-methylcyclohexene, and α-ionone were efficiently oxidized with O 2 in the presence of Co (II) complex and butyraldehyde at 55 °C. A simple treatment of the resulting products led to epoxides as predominant products and a small amounts of allylic oxides, the chemoselectivity for the former being 82.1 - 90.8% with a 70.6 - 98.6% substrate conversion. On the other hand, oxidation of 1-phenylcyclohexene, 1-cyclohex-1-enylethan-1-one, α-pinene, and β-pinene gave allylic oxides as major products.

Structure / Activity Correlations of Hydrogenation Catalysts The reason for different activities of group VIII metal catalysts in several hydrogenation reactions is unknown. The activity of group VIII metal catalysts decreases in the hydrogenation of crotonaldehyde to butyraldehyde in the following sequence Pd > Pt > Ni > Rh > Co; Ir. However in the hydrogenation of butyraldehyde to butanol the sequence of metals is inversely. The hydrogenations of crotonaldehyde and butyraldehyde proceed as ligand addition reactions. The reaction rate depends on the nucleophilicity of atomically chemisorbed hydrogen. Whereas the reaction rate in the hydrogenation of crotonaldehyde increases, the hydrogenation rate of butyraldehyde decreases with the nucleophilicity of atomically chemisorbed hydrogen.

The aldol reactions of propionaldehyde and butyraldehyde have been explored in supercritical CO2, scCO2, using an automated continuous flow reactor. The reaction was found to proceed over a variety of heterogeneous acidic and basic catalysts and with increased selectivity compared to using neat reactants.

1,3-Dipolar cycloadditions of azomethine imines 3a and 3b, available by acid-catalyzed treatment of 3-pyrazolidinone 1 with acetone (2a) and butyraldehyde (2b), respectively, were studied. Reactions of 3a with DMAD (4) afforded a mixture of products 9 and 10a, whilst treatment of 3b with DMAD (4) gave a mixture of compound 9 and epimeric cycloadducts 10/10′b. On the other hand, cycloadducts 13a,b-16a,b were isolated as single diastereomers in 9–37% yields upon reactions of 3a,b with olefinic dipolarophiles 5–8. The structures of cycloadducts 9, 10a, 10/10′b, and 13a,b-16a,b were determined by 1H nmr and NOESY spectroscopy. The structure of compound 13a was confirmed by X-ray diffraction.

The sporicidal efficacy of glutaraldehyde (2% w/v) was investigated under various conditions. Numerous factors influenced its activity: method of spore production, inherent spore resistance characteristics, alkalination, storage time and storage temperature. The sporicidal action of 2% alkaline glutaraldehyde at room temperature was compared with that of other aldehydes and commercially available formulations. Cidex (glutaraldehyde) and Sporicidin (glutaraldehyde + phenol full strength) were the most effective, followed by 8% (w/v) formaldehyde and 10% (v/v) Gigasept, a formaldehyde-containing product. Five per cent (v/v) Gigasept and 10% (w/v) glyoxal also had good sporicidal activity, though that of Sporicidin (1 : 16) was poor. No activity was observed with 10% (w/v) butyraldehyde.