Butylmagnesium Chloride Research Articles

Capping Agents Enable Well-Dispersed and Colloidally Stable Metallic Magnesium Nanoparticles.

Mg nanoparticles are an emerging plasmonic material due to Mg's abundance and ability to sustain size- and shape-dependent localized surface plasmon resonances across a broad range of wavelengths from the ultraviolet to the near infrared. However, Mg nanoparticles are colloidally unstable due to their tendency to aggregate and sediment. Nanoparticle aggregation can be inhibited by the addition of capping agents that impart surface charges or steric repulsion. Here, we report that the common capping agents poly(vinyl) pyrrolidone (PVP), polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS) interact differently and have varied effects on the aggregation and colloidal stability of Mg nanoparticles. Nanoparticles synthesized in the presence of PVP showed improvements in colloidal stability and reduced aggregation, as observed by electron microscopy and optical spectroscopy. The binding of PVP was confirmed through infrared and X-ray photoelectron spectroscopy. The influence of PVP on the reduction of di-n-butyl magnesium was evaluated through analysis of particle size distribution and Mg yield as a function of reaction time, reducing agent, and temperature. Furthermore, the presence of PVP drastically changes the growth pattern of metallic Mg structures obtained from the reduction of the Grignard reagents butylmagnesium chloride and phenylmagnesium chloride by lithium naphthalenide: large polycrystalline aggregates and well-separated faceted nanoparticles grow without and with PVP, respectively. This study provides new synthetic routes that generate colloidally stable and well-dispersed Mg nanoparticles for plasmonic and other applications.

Study on analytical method for methlmecury in sediment by gas chromatography-atomic fluorescence spectrometry using Grignard reagcuts for alkylation

The analytical method for methylmercury in sediment samples was performed using an hyphenated system of gas chromatograph coupled atomic fluorescence detector (GC-AFS). Methylmercury in sediment samples was leached and extracted into dichloromethane with the assistance of HNO3, KCl and CuSO4. Dichloromethane was evaporated resulting in the relocation of MeHg to the aqueous phase. MeHg was then extracted in the form of diethyldithiocarmate complex into hexane followed by the alkylation processes with Grignard reagents, butyl magnesium chloride and ethyl magnesium chloride. The alkylation reactions were optimized with respect to the mounts of Grignard reagents, the reaction temperature and time for the best alkylation yields and least extent of trans-alkylation and degradation of the alkylated products. The alkylated MeHg compounds were analyzed by GC-AFS. The analytical method for methylmercury was validated using certified reference material ERM-CC580. The instrumental limit of detection was 1.4 pg as Hg. The method limits of detection for EtMgCl and BuMgCl were 0.18 were 0.18 ng/g and 0.19 ng/g, respectively. This method can be used to analyze MeHg in sediment samples.

Identification of Mercury Species in Liquid Hydrocarbons

Crude oil and natural gas may contain traces of mercury depending on the origin. Mercury contamination of oil feedstocks may cause problems in both upstream and downstream operations. Mercury also has toxic effects on human health. Therefore, mercury should be removed from oil and natural gas products at the production facility before shipping. Identification of the mercury species in hydrocarbons is very important for effective removal from oil and gas. Mercury species analysis was investigated using GC-ICP-MS. Metallic mercury analysis used various sample injection procedures for GC. Ionic mercury analysis compared Grignard (butylmagnesium chloride) with sodium tetraphenylborate agents for the derivatization technique and confirmed that both reagents provided good results. The present study optimized mercury species analysis for liquid hydrocarbons using GC-ICP-MS.

Visualization of Mg Electrodeposition and Dissolution in Halo-Mg Complex Forming Electrolytes

The development of rechargeable Mg batteries, driven by the desire to surpass the limiting specific energy density of Li ion batteries, is currently limited by the lack of high voltage cathodes and stable, functional electrolytes. Few electrolytes are capable of delivering the magnesium cation to the anode surface in a form that readily undergoes de-solvation and without formation of a cation blocking surface film. To date, successful reported electrolyte strategies take advantage of the creation of a magnesium ion complex where the cation traditionally is delivered through a Grignard reagent or MgCl2and more recently using organoborate or borohydride compounds. Generally not considered as significant is the existence of films on the magnesium surface that regulate the rates of charge transfer and metal accommodation. In this paper, we demonstrate the presence and impact of such surface films when halo-Mg complexes are employed.The physical presence of a surface film can be captured though electrochemical atomic force microscopy measurements. Figure 1a shows the electrodissolution of Mg(0001) orieneted crystallites deposited on an Au(111) electrode in a 0.5 M phenylmagnesium chloride:tetrahydrofuran electrolyte. Potentiostatic dissolution of the crystallites at 40 - 50 mV vs. Mg produces direct evidence of a surface film as a significant fraction of the crystallites exhibit highly localized dissolution. Dissolution is observed to start either near the center of a (0001) facet or on a perimeter facet as the surface film is locally disrupted and anodic dissolution of the underlying Mg occurs. An “exo-skeleton” is observed to form from the remnant film as dissolution nears completion. These results suggest that localized film breakdown is a prerequisite step in the electrodissolution of equilibrated Mg deposits.The presence of a surface film raises questions concerning its properties and impact on electrochemical deposition/dissolution rates. We demonstrate that the surface film that forms in a 1 M Butylmagnesium chloride:Butyl diglyme electrolyte is electrically conductive. A freshly activated Mg surface is allowed to equilibrate for 0 to 30 min, during which film formation may occur, followed by deposition of a Mg adlayer. Galavanostatic stripping of the resulting film (Figure 1b) demonstrates potentiometric signatures corresponding to adlayer dissolution (region a), film perturbation (region b), and underlying Mg substrate dissolution (region c). The persistence of the now buried film, as evidenced by the large dissolution potential excursion at 120 s (the time required to strip the Mg adlayer at near 100% coulombic efficiency), demonstrates that Mg adlayer deposition and dissolution were accomplished without prior removal of the film. Mg adlayer deposition and dissolution argues that the film is conductive since these electrochemical processes would be impossible at such modest overpotentials otherwise.In this paper, we have extended this work to examine whether evidence of film formation exists for the broader class of MgCl2:Lewis acid supporting electrolytes. The absence of a strong reducing agent in the case of non-Grignard electrolytes raises questions of how residual water and oxygen impact the Mg deposition process and the cycling efficiency of Mg anodes as a whole. By visualizing Mg deposition in a range of halo-Mg electrolytes we attempt to understand how differences in surface film properties affect Mg nucleation, growth, and dissolution. This work is supported as part of the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. DOE’s NNSA under contract DE-AC04-94AL85000.

Development of a practical and sustainable strategy for the synthesis of ST1535 by an iron-catalyzed Kumada cross-coupling reaction

A simple, convenient, and environmentally friendly route to ST1535 employing an iron-catalyzed cross-coupling reaction and butylmagnesium chloride is described.

ChemInform Abstract: Nucleophilic Trifluoromethylation of Anhydrides Employing (Trifluoromethyl)trimethylsilane: Synthesis of γ‐Trifluoromethylated γ‐Butyrolactones.

AbstractAlkyl Grignard reagents, apart from MeMgCl, react similar to butyl magnesium chloride, giving the undesired side product (VI).

Introduction of bulky tert-butyl substituents on the core of N,N′-diaryl N-heterocyclic carbenes through the corresponding vicinal diamines

Highly bulky N , N ′-diaryl imidazolinium salts substituted by one or two tert -butyl groups on the heterocyclic backbone and the corresponding silver N -heterocyclic carbene complexes are obtained by the addition of tert -butyl magnesium chloride or tert -butyl lithium on symmetrical 1,2-bisimines derived from 2,6-diisopropylaniline, 2,6-diethylaniline and 2,4,6-trimethylaniline.

Accuracy profile validation of a new analytical method for butane measurement using headspace-gas chromatography–mass spectrometry

The aim of our study was to provide an innovative HS-GC/MS method applicable to the routine determination of butane concentration in forensic toxicology laboratories. The main drawback of the GC/MS methods discussed in literature concerning butane measurement was the absence of a specific butane internal standard necessary to perform quantification. Because no stable isotope of butane is commercially available, it is essential to develop a new approach by an in situ generation of standards. To avoid the manipulation of a stable isotope-labelled gas, we have chosen to generate in situ an internal labelled standard gas (C4H9D) following the basis of the stoichiometric formation of butane by the reaction of deuterated water (D2O) with Grignard reagent butylmagnesium chloride (C4H9MgCl). This method allows a precise measurement of butane concentration and therefore, a full validation by accuracy profile was presented.

Morphology and Preferred Orientation of Pulse Electrodeposited Magnesium

A nanocrystalline magnesium material with a high specific surface area is expected to react rapidly and reversibly with hydrogen gas to yield magnesium hydride, a hydrogen storage medium. In this paper, the feasibility of the synthesis of magnesium materials for hydrogen storage applications by pulse electrodeposition of magnesium from ethereal electrolytes containing Grignard reagents was investigated. Deposition onto flat stainless steel electrodes established that, as in dc deposition, the morphology of the deposits varied widely with electrolyte composition and charge density. Irregular, nanocrystalline magnesium films were formed at low current density and low charge density using butylmagnesium chloride electrolytes in dibutyl diglyme, while at a higher current density in tetrahydrofuran, dense films were favored.

Kinetics of the grignard reaction with silanes in diethyl ether and ether-toluene mixtures.

Kinetics of the reactions of butylmagnesium chloride and phenylmagnesium bromide with tetraethoxysilane and methyltrichlorosilane was investigated in diethyl ether and diethyl ether-toluene mixtures. Replacement of ether by toluene significantly accelerates the reaction with alkoxysilanes, while no effect was found for the reaction with chlorosilanes. We established that the reaction with alkoxysilanes consists of replacement of a donor molecule at the magnesium center by the silane followed by subsequent rearrangement of the complex to products through a four-center transition state. Chlorosilanes react differently without solvent molecule replacement but also via a four-center transition state. Large negative activation entropies are consistent with formation of cyclic transition states. Small activation enthalpy values together with remarkable exothermicity point to early transition states of the reactions.

Electrochemical Synthesis of Alkyl Nitroaromatic Compounds.

AbstractFor Abstract see ChemInform Abstract in Full Text.

XPS Investigation of Surface Chemistry of Magnesium Electrodes in Contact with Organic Solutions of Organochloroaluminate Complex Salts

Metallic magnesium can be reversibly deposited from ethereal solutions of magnesium−aluminum complex salts of the general structure Mg(AlCl4-nRn)2, where R = alkyl. In contrast to the case of lithium surfaces, already thoroughly investigated, the surface state of magnesium electrodes in contact with organic solutions is yet unclear. In this paper we report on a systematic surface analysis of magnesium electrodes in contact with various organic solutions, using XPS. We find in both clean tetrahydrofurane (THF) and THF solutions of dibutylmagnesium or butylmagnesium chloride that the metal surface consists of magnesium oxide and hydroxide (probably developed during manipulation and sample transfer); however, it does not develop thick passivation layers. In THF solutions containing Mg(AlEtBuCl2)2, surface residuals of carbon, aluminum, and chlorine are detected yet are restricted to the outermost part of the surface, as physically adsorbed species. From their concentration one deduces that both the complex salt and the ether are not reduced at the magnesium surface but precipitate as an insoluble film. Metallic magnesium deposited from THF/Mg(AlEtBuCl2)2 solution on gold electrodes shows a very similar surface chemistry, providing an additional proof that, even in the most frail conditions available during electrochemical deposition, pure magnesium is deposited. The surface chemistry of magnesium in contact with propylene carbonate (PC) exhibits as well layered surface chemistry, most of it composed of magnesium oxide and hydroxide, but no evidence is found for reduction products of PC. It is concluded that the magnesium metal behaves like a surface film-free electrode in organo-haloaluminate/THF solutions. Our conclusions support several other studies on the properties of magnesium in such solutions.

Solvation Effects in the Grignard Reaction with Carbonyl Compounds

AbstractRatios of the yields of addition and reduction products for the reactions of butylmagnesium chloride with diisopropyl ketone, methyl 2‐methylpropanoate, and isopropyl 2‐methylpropanoate in toluene were determined at different THF, diethyl ether, and tert‐butyl methyl ether contents in the Grignard reagent. Replacement of the alkoxy group in the ester leads to strikingly different results for very small additions of donors. The results are discussed in terms of the solvation of the species in the reaction mixture.

Electrochemical synthesis of alkyl nitroaromatic compounds.

Alkyl nitroaromatic compounds were readily prepared via nucleophilic aromatic substitution for hydrogen or a heteroatom by electrochemical oxidation of the sigma-complex. Butyllithium and butylmagnesium chloride were used as nucleophiles, and several nitrocompounds were tested to explore the possibilities of the NASH and NASX reactions promoted electrochemically.

Reaction pathways towards 1,1,2,2-tetra tbutyldistannanes

1,2-Dichlorotetra t butyldistannane ( 1) is synthesized as a byproduct in the reaction of t butylmagnesium chloride with tin tetrachloride or by the reaction of di t butyltindihydride with di t butyltin dichloride in the presence of amines. Reaction of 1 with lithium aluminumhydride yielded the dihydrido derivative 2. The treatment of 2 with bromoform gave the dibromo distannane 3 nearly quantitatively. Reactions of 2 with one equivalent of LDA or KH yielded unsymmetrically substituted alkali metal distannanes of the type M t Bu 2SnSn(H) t Bu 2 ( 4, M=Li; 5, M=K). Reaction of either two equivalents of KH with 2, or one equivalent of KH with 5 gave the dipotassium distannide 6. The molecular structure of the dichloro derivative 1 was determined by X-ray diffraction.

Determination of the speciation of organolead compounds in airborne particulate matter by gas chromatography–inductively coupled plasma mass spectrometry

The speciation of organolead compounds in airborne particulate matter was determined by gas chromatography–inductively coupled plasma mass spectrometry. The analytes were extracted from the sample using 0.5 M acetic acid in methanol. The ionic organolead compounds were extracted into hexane using diethydithiocarbamate at pH 9 in the presence of EDTA to complex inorganic Pb. Derivatisation of the organolead species was performed with butylmagnesium chloride. Separation and detection of the butylated trimethyllead (TML), dimethyllead (DML), triethyllead (TEL) and diethyllead (DEL) was achieved. Detection limits, as Pb, were 3.2 fg for TML, 2.4 fg for DML, 1.8 fg for TEL and 9 fg for DEL for a 1 μl sample injection. Typical precision of repetitive injections was 1.5–4% using tetraethyllead (TrEL) as internal standard. The method proposed was validated by the determination of TML in the reference material CRM 605 and was applied to the analysis of airborne particulate matter in the atmosphere of the city of Oviedo. DML, DEL and methylethyllead (MEL) were detected at pg m −3 levels.

1,2]-Wittig Rearrangement of Acetals III [1]. New 1,2-Alkoxyalcohols, 1,2-Alkoxyaminesand 1,2-Dialkoxy Compounds as Chiral Ligands for Organomagnesium and Organolithium Compounds and forLithium Aluminum Hydride

Eight O-substituted 1,2-diols and one O,N-substituted 1,2-aminoalcohol derived from 2-alkoxyoctahydro-7,8,8-trimethyl-4,7-methanobenzofurans via a [1,2]-Witting rearrangement and subsequent substitution were synthesized and tested as additives for the enantioselective addition of butyllithium and butylmagnesium chloride to benzaldehyde and for the reduction of acetophenone with lithium aluminum hydride. The selectivity of the reactions was determined by GC of the obtained 1-phenyl-1-pentanol and 1-phenylethanol on a chiral phase. Best results with regard to selectivity (52% ee and 94% ee, resp.) were achieved in the formation of 1-phenyl-1-pentanol by addition of the substituted 1,2-aminoalcohol to the organometallic reagent and in the reduction of acetophenone using an α-alkoxyalcohol (62%ee).

Approach to Enantioselective Conjugate Addition of Organocopper Reagents to Cycloalkenones by the Aid of Chiral Lactam Bearing Phosphine Group

The chiral lactam-phosphine ligand and copper salt mediated asymmetric conjugate addition reaction of butylmagnesium chloride and diethylzinc with cycloalkenones afforded the addition products in moderate selectivity. Among phosphines examined, 5-[(diphenylphosphino)methyl]-3,3-dimethylpyrrolidin-2-one 5 gave rise to moderate enantioselectivity and high yield.

Mercury speciation by capillary gas chromatography with radiofrequency hollow cathode glow discharge atomic emission detection

Hollow cathode (HC) glow discharge (GD) atomic emission spectrometry (AES) with a radiofrequency (rf) source was investigated as a detector in gas chromatography (GC) for elemental speciation of methylmercury, ethylmercury and inorganic mercury following a Grignard derivatisation reaction (butylmagnesium chloride). The HC design and the transfer line between the source and the GC column are described; in addition, the parameters governing the discharge (pressure, He flow rate, rf power) on the emission of the analytes were optimised. The analytical performance characteristics of this hyphenated technique were evaluated and compared with those of other more common plasmas used as atomic detectors in GC. The absolute detection limits were found to be 0.2, 0.2 and 0.3 pg for methylmercury, ethylmercury and inorganic mercury, respectively, with the variability being lower than 8% RSD at the 10 pg level. Finally, the accuracy of the proposed methodology was successfully tested by analysing two certified reference materials from the National Research Council of Canada (DORM-2 and DOLT-2).

Sources of systematic errors in mercury speciation using Grignard reagents and capillary gas chromatography coupled to atomic spectrometry

This paper describes spectral and chemical interferences that occurred when using Grignard reagents for derivatisation of mercury species and microwave-induced plasma atomic emission (MIP-AES) or atomic absorption spectrometry for detection. When butylmagnesium chloride, dissolved in THF, was used to convert methyl and inorganic mercury to non-polar butyl derivatives it was established that reaction by-products, eluted near to the methylbutylmercury peak, caused changes in the background emission or absorption. The use of other Grignard reagents, pentyhnagnesium bromide and hexylmagnesium bromide, was investigated. These showed poor derivatisation efficiency and species stability. Iodide and bromide at concentrations of the order of 1 mg 1 −1 were found to de-alkylate organic mercury species when present in an organic matrix. In addition, if these halides were not completely removed from the GC column under a normal chromatographic run, they reacted with derivatised mercury species in subsequently injected samples. Organomercury iodide or bromide compounds were formed and these were identified by GC-MS. This reaction reduced the signal magnitude for dibutylmercury, corresponding to inorganic mercury. Replacement of indigenous methyl groups with butyl groups was demonstrated on prolonged contact of samples containing methyl and dimethylmercury with butylmagnesium chloride. The degree of methyl group replacement appeared to be proportional to the reaction time.