Copolymerization of two bromine containing methacrylate monomers with methylmethacrylate. Determination of reactivity ratios by in situ quantitative 1H NMR monitoring

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Ichim Ionut Cameliu ◽  
Marius Ciprian Rusu ◽  
Mihai Rusu ◽  
Popa Marcel ◽  
Christelle Delaite ◽  
...  
Keyword(s):  
Side Chain ◽  
Random Structure ◽  
Reactivity Ratios ◽  
Medical Implants ◽  
Propyl Methacrylate ◽  
H Nmr ◽  
Methacrylate Monomers ◽  
Methacrylic Monomers

AbstractAn important method used to make medical implants radiologically visible is based on introduction of radiopaque bromine or iodine containing methacrylic monomers. Thus, 2-(2-bromopropionyloxy) propyl methacrylate (BPPM) and 2-(2-bromoisobutyryloxy) propyl methacrylate (BIPM) were synthesized with the aim to use them as radiopaque agents. The free radical initiated copolymerization of BPPM and BIPM with methyl methacrylate (MMA) were performed directly in a thermostatic cell of the NMR spectrometer. The copolymer compositions obtained from 1H NMR spectra led to the determination of the reactivity ratios (rMMA = 1.08 ± 0.12; rBPPM = 1.01 ± 0.13 and rMMA = 0.95 ± 0.09; rBIPM = 0.95 ± 0.1). The reactivity ratios of these two monomers is similar to that of MMA suggesting that the length of the bromine containing monomers side chain does not affect significantly the reactivity of the methacrylic double bond. From the results we conclude the copolymers to have random structure.

The poly(propylene oxide-co-ethylene oxide) gradient is controlled by the polymerization method: determination of reactivity ratios by direct comparison of different copolymerization models

2019 ◽  
Vol 10 (22) ◽  
pp. 2863-2871 ◽  
Author(s):  
Jan Blankenburg ◽  
Erik Kersten ◽  
Kamil Maciol ◽  
Manfred Wagner ◽  
Sirus Zarbakhsh ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Ethylene Oxide ◽  
Propylene Oxide ◽  
Reactivity Ratios ◽  
H Nmr ◽  
Poly Propylene ◽  
Polymerization Method

An investigation of the copolymerization of EO and PO by in situ1H NMR spectroscopy reveals striking differences in the monomer gradient, depending on the polymerization method.

Revision of the structure of 3-methoxy-14α-hydroxy-D-homo-1,3,5-(10)-estratrien-17a-one. A simple 1H NMR method for the determination of configuration of hydroxy group in position 5 and/or 14 of the D-homo-steroid skeleton

1991 ◽  
Vol 56 (7) ◽  
pp. 1512-1524 ◽  
Author(s):  
Miloš Buděšínský ◽  
Alexander Kasal ◽  
Želimír Procházka ◽  
Huynh Kim Thoa ◽  
Soňa Vašíčková ◽  
...  
Keyword(s):  
Hydroxy Group ◽  
Chemical Shifts ◽  
Cotton Effect ◽  
Hydroxyl Group ◽  
H Nmr ◽  
Nmr Method ◽  
Synthetic Models ◽  
Steroid Skeleton

Eignerova and Prochazka found in 1974 the Cotton effect value for 3-methoxy-14α-hydroxy-D-homo-1,3,5(10)-estratrien-17a-one (Ia) to be Δε – 2.76.Calculation of the Δε value for this compound led, however, to a substantially lower value, which suggested the hypothesis that the compound was in fact rather an epimer with the hydroxy group in position 14β. This hypothesis was studied by means of 1H NMR spectra of synthetic models, using the changes of the chemical shifts of angular methyls, induced by in situ acylation of the angular hydroxyl with an α- or β-configuration with trichloroacetyl isocyanate (TAI). The observed TAI-acylation shifts on model compounds indicated the structure Ib with a 14b-configuration of the hydroxyl group. Indenpendent proof has been given by the synthesis of both 14-hydroxy epimers, Ia and Ib. A simple 1H NMR method is proposed for the determination of configuration of the hydroxyl in position 5 or 14 of D-homo-steroid skeleton.

Synthesis, third-order nonlinear optical (NLO) properties of polystyrene containing 1,8-naphthalimide chromophores in the side chain

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Jin Zhengneng ◽  
Li Najun ◽  
Lu Jianmei ◽  
Xu Qingfeng ◽  
Xia Xuewei ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Side Chain ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Third Order ◽  
Nlo Properties ◽  
H Nmr ◽  
The Third ◽  
Methoxy Groups ◽  
Methacrylate Monomers

AbstractTwo novel methacrylate monomers, (4-((methacryloyloxy)-hexyloxy)- benzylidene-hydrazine)-N-(4-alkyloxy)-benzene-1,8-naphthalimide (NAOPH) and (4-((methacryloyloxy)-hexyloxy)-3,5-dimethoxy-benzylidene-hydrazine)-N-(4-alkyloxy)- benzene-1,8-naphthalimide (NA3OPH) were synthesized. The polystyrenes containing 1,8-naphthalimide chromophores were prepared by copolymerization of styrene with NAOPH or NA3OPH. The obtained copolymers were characterized by GPC, 1H-NMR and TLC. The third-order NLO properties of the monomers and copolymers were measured by Z-scan technique. Results show that both monomers and copolymers have reverse saturable absorption (RSA) and selfdefocusing effects. For monomers, NA3OPH has larger third-order NLO susceptibility χ(3) than NAOPH due to introduction of two more methoxy groups. For all copolymers, larger χ(3) is observed when content of 1,8-naphthalimide chromophores was higher.

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

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