Vinicius Caliman

• Chemistry
• Federal University of Minas Gerais

Enhanced oil recovery aims to increase the sweeping efficiency of a reservoir through the injection of displacing fluids. The use of preformed particle gels (PPG) has recently received great attention because it acts by blocking the high permeability channels, reducing water production and elevating the cost/benefit for production. Herein, an innov...

Malachite green (MG) is used for the dyeing of cotton, paper, and jute, among other materials, and presents acute toxicity to a wide range of aquatic and terrestrial animals. A polyacrylamide (PA) hydrogel modified with a low content of oxygenated and aminated carbon nanomaterials may be a suitable candidate to adsorb MG from wastewater. Herein, gr...

Malachite green (MG) is used for the dyeing of cotton, paper, and jute, among other materials, and presents acute toxicity to a wide range of aquatic and terrestrial animals. A polyacrylamide (PA) hydrogel modified with a low content of oxygenated and aminated carbon nanomaterials may be a suitable candidate to adsorb MG from wastewater. Herein, mo...

Partially hydrolyzed polyacrylamide (HPAM) aqueous fluids in reservoirs produces a significant increase in the produced oil volume. However, the viscosity of these fluids is highly influenced by the temperature and salinity of the medium which is crucial in some reservoir conditions for the oil recovery. Thus, addition of nanomaterials in HPAM solu...

Few layers graphene oxide (GO), graphene oxide functionalized with diethylenetriamine (GO-DETA) and the hybrid of graphene oxide-diethylenetriamine and polyacrylamide (GO-DETA/PAM) hydrogel with high adsorption of methylene blue were prepared using microwave-assisted methods. TGA and XPS analysis were performed to confirm DETA molecules incorporati...

The use of nanofluids for industrial applications depends on its stability during transport and use. In this work, we demonstrate that graphene oxide (GO)-based aqueous nanofluids can remaining stable for as many as 90 days. The structural and morphological analyses showed that the GO samples have an average thickness of two graphitic layers with i...

Polymer aqueous nanofluids have numerous industrial applications due to their synergic properties as a polymer and nanoparticle in the same fluid. The main goal of this work was to prepare stable aqueous nanofluids with improved viscosity in high temperature and salinity conditions. Aminated carbon nanotube (OCNT-TEPA) presented a CN photoemission...

Few-layered graphene oxide (GO) was prepared using a fast and energy-saving method by microwave-assisted acid technique. The oxygenated groups existing on the GO surface were determined using UV-Vis, X-ray photoelectron and Fourier-transform infrared spectroscopies. An oxygenated group percentage of 30% in mass for the GO was observed by thermograv...

Carbon black was oxidized (OCB) and added in the concentrations from 0.05 to 0.50 wt% to various aqueous solutions containing Poly(acrylamide-co-acrylic acid 1 wt%) in concentration of 3.0 g L−1. The nanofluids' viscosity were measured during 150 days and showed that small amount of the OCB nanoparticles improved the viscosity and the stability of...

The rheological behavior of aqueous nanofluids formed by polyacrylamide (PAM) and different concentrations of carbon nanotubes (CNT) has been investigated. The overlap concentration, molecular size, and mass of PAM were first obtained from viscometry of dilute samples. Determination of the critical concentration of PAM directed the preparation of n...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Poly(ethylene oxide) and poly[bis[2-(2′-methoxyethoxy) ethoxy] phosphazene], PEO/MEEP, polymer blends were investigated by thermal analysis, X-ray diffraction, and atomic force microscopy. MEEP is an amorphous polymer and its semicrystalline blends with PEO showed two distinct glass transitions, whose composition dependence was analysed by the Lodg...

Polímeros condutores iônicos ou eletrólitos poliméricos constituídos por um sistema de sal dissolvido em uma matriz polimérica sólida são materiais que apresentam interesse científico e potencial tecnológico. A dissolução de sais em uma matriz polimérica amorfa ou semicristalina sólida leva a estudos sobre intrigantes aspectos estruturais, que pode...

Ionic conducting polymers or polymer electrolytes prepared with the addition of a soluble salt in a solid polymeric matrix are very important materials, associated with an intense research activity and technological efforts. Structural studies in a system of salt dissolved in an amorphous or semicrystalline solid polymeric matrix can be done with v...

Reaction of Li(P3C2Bu t2 ) with BrCH(SiMe3)2 results in a novel organophosphorus compound with the formula, P6C4Bu t4 CHSiMe3 (1). Compound 1 was fully characterised spectroscopically and its unique molecular structure determined by single crystal X-ray diffraction. Another isomer (2) with a saturated structure was also fully characterised.

The synthesis of two new arsadiphospholes of formula (AsP2C2Bu t2 )CH(SiMe3)2, from 4-arsa-1,2-diphosphacyclopentadienyl and 2-arsa-1,4-diphosphacyclopentadienyl ring anions are reported together with their characterization by 31P NMR. Ab initio calculations at the MP2/6-31G(d) level of theory were carried out to investigate the energy barrier for...

Protonation of the lithium triphospha-cyclopentenyl salt Li (P3C2But2RR′) (R=(Me3Si)2CH-, R′=Bun) with HCl affords the new 2,3-dihydro-1H-[1,2,4] triphosphole P3C2But2(H) (Bun)CH(SiMe3)2 which has been structurally characterised as its [W(CO)5] complex.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The chemistry of cyclopentadiene rings has been widely studied. This review article deals with a similar chemistry of new compounds containing from 1 to 5 phosphorus atoms on the ring substituting the carbon atoms. The neutral rings containing one, two and three phosphorus atoms can be used as building blocks for the synthesis of new organic compou...

The syntheses, structures, and reactivities of new (η6-arene)tricarbonylchromium compounds bearing propargylamines are described. The reaction of (η6-C6H5Cl)tricarbonylchromium with propargylamines affords YCH(R)CCPh[Cr(CO)3] (1a, R = H, Y = NMe2; 1b, R = Me, Y = NMe2; 1c, R = H, Y = N(Me)(CH2Ph)) in good yield. The reaction of 1a,b with Li2PdCl4 g...

The first examples of η1-complexes of 1,2,4-triphospholes are reported in which the ring acts as a 2e and a 4e donor. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:1–8, 1998

Room temperature electrocyclisation of the 1,2,4-triphosphole P3C2But2CH(SiMe3)2 affords the new 1,3,5-triphosphabicyclo[2.1.0]pent-2-ene which undergoes a very rapid [1,3]-phosphorus migration which can be stopped by coordination of [W(CO)5]; the two isomeric phosphorus compounds react differently with [PtCl2(PEt3)]2, the latter via an insertion o...

In the nickel(II) complex [Ni(eta(5)-P3C2Bu2t)(eta(2)-(P3C2Bu2CH)-C-t-(SiMe3)(2)Me}] the triphosphacyclopentenyl ring (P3C2BU2CH)-C-t(SiMe3)(2)Me is unexpectedly coordinated to the metal exclusively via the two adjacent saturated ring phosphorus atoms, rather than via the 2-phosphaallyl fragment.

Evidence for an η 5 -ligated 1,2,4-triphosphole ring system which exhibits some aromatic character is presented via the first syntheses, structural and theoretical studies of η 5 -1,2,4-triphosphole metal tricarbonyl complexes of zerovalent Cr, Mo and W.

The molecular structures of the [4 + 2] cycloaddition products of (i) 1,3-diphosphacyclopentadiene with itself and (ii) with 1,2,4-triphosphacyclopentadiene are presented and mechanistic differences discussed in relation to the ‘cage’ product P6C4tBu4H2 which is formed from the [4 + 2] and [2 + 2] self-cycloaddition reactions of 1,2,4-triphosphacyc...

The first examples of platinum(II) complexes of the P4C4Bu4 and P5C5Bu5 “cages” are described and detailed nmr and X-ray crystallographic structural studies have been carried out on the complexes trans-[PtCl2(PR3)(P4C4Bu4 )], trans-[(PtCl2(PR3)]2(P4C4Bu4 )], (R = Et, Bu), and trans-[PtCl2(PEt3)-(P5C5Bu5 )].

The activation barrier for the [1, 3]-phosphorus migration in the title compound is estimated (MP4SDTQ/6–31 G*//MP2/6–31 G*+ ZPE) to be 11.62 kcal mol–1(1 cal = 4.184 J), which is considerably smaller than the barrier (31.13 kcal mol–1) for [1,3]-carbon migration in the corresponding hydrocarbon.

The first known triphosphole exhibits different modes of ligation to transition-metal centres.

Constructed from six phosphaalkyne units, the organophosphorus compound P6C6tBu6 (1) can be considered to have a structure derived from the corresponding tetraphosphacubane in which two opposite carbon corners have been replaced by CCP rings. The hexamer 1 therefore has the same structure as the D3d symmetric (CH)12 hydrocarbon p-[3².5⁶]octahedrane...

The use of the P3C2Bu 2 and P2C3Bu 3 rings in (i) the synthesis of the novel hexameric P6C6Bu 6 “cage” and (ii) the first 1,2,4-triphosphacyclopentadiene and its metal complexes is described.

Introduction Solid polymeric electrolytes (SPE) received considerable attention since the 70s and, nowadays, scientists are searching for materials with mechanical and thermal stability for practical applications. PEO -poly(ethylene oxide) -was the first polymer used as a matrix for polymeric electrolytes, however its crystallinity was not appropri...

Thesis (Ph. D.)--University of Sussex, 1996.