To see the other types of publications on this topic, follow the link: Dimethyl Acetal.
Dissertations / Theses on the topic 'Dimethyl Acetal'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 15 dissertations / theses for your research on the topic 'Dimethyl Acetal.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Johannesson, Petra. "Synthesis of Aldehyde-Functionalized Building Blocks and Their Use for the Cyclization of Peptides : Applications to Angiotensin II." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2002. http://publications.uu.se/theses/91-554-5211-6/.
Full text
2
Intharapat, Punyanich. "Thermoplastic natural rubbers based on natural rubber (NR) and ethylene vinyl acetate copolymer (EVA) with natural rubber-graft- poly(dimethyl(methacryloyloxymethyl)phosphonate) (NR-g-PDMMMP) as compatibilizer." Le Mans, 2009. http://cyberdoc.univ-lemans.fr/theses/2009/2009LEMA1005.pdf.
Full textAbstract:
Des copolymères greffés à base de caoutchouc naturel (NR) et de poly(acryloyloxyméthylphosphonate de diméthyle) (NR-g-PDMAMP), de poly(méthacryloyloxyéthylphosphonate de diméthyle) (NR-g-PDMMEP) et de poly(méthacryloyloxyméthylphosphonate de diméthyle) (NR-gPDMMMP), ont été synthétisés en milieu latex selon la méthode dite « grafting from » à partir de sites amorceurs photosensibles N ,Ndiéthyldithiocarbamate préalablement introduits le long des chaînes 1,4-polyisoprène du caoutchouc naturel. Des études de compatibilisation des mélanges caoutchouc naturel (NR) / copolymère d'éthylène - acétate de vinyle (EV A) ont par la suite été envisagées avec le copolymère NR-gPDMMMP, choisi comme agent compatibilisant. Elles ont été effectuées sur des mélanges simples 50/50 NR/EV A, mais aussi des mélanges dynamiquement vulcanisés 40/60 NR/EVA. Dans les deux cas,les influences du taux de greffage du NR-g-PDMMMP (71, 80, 89, et 95%) et du taux de chargement en compatibilisant (0, 1,3,5,7,9,12, et 15 % en poids par rapport au NR) sur les propriétés rhéologiques, dynamiques, mécaniques, morphologiques, et thermiques, ont été étudiées. Les meilleurs effets de compatibilisation ont été observées avec un copolymère NR-g-PDMMMP ayant un taux de greffage de 80 %, pour un taux de chargement de 7 % dans le cas du mélange simple 50/50 NR/EV A et de 9 % dans celui du mélange dynamiquement vulcanisé 40/60 NR/EV A. Les études microscopiques par SEM des mélanges ont montré une réduction de la taille des domaines. Il a aussi été noté que la stabilité thermique du mélange NR/EVA se trouve renforcée avec l'incorporation du NR-g-PDMMMPGraft copolymers of natural rubber and poly(dimethyl(acryloyloxymethyl)phosphonate) (NR-g-PDMAMP), natural rubber and poly(dimethyl(methacryloyloxyethyl)phosphonate) (NR-g-PDMMEP), and natural rubber and poly(dimethyl(methacryloyloxymethyl)phosphonate) (NR-g-PDMMMP), were prepared in latex medium via a "grafting from" methodology based on the photopolymerization of vinyl monomers initiated from N,N-diethyldithiocarbamate groups previously bound in side position of the 1,4-polyisoprene chains of natural rubber. Thereafter, compatibilization studies of natural rubber (NR) / ethylene vinyl acetate copolymer (EV A) blends were considered using NR-g-PDMMMP as a blend compatibilizer. The investigations were carried out on two categories of blends : uncured 50/50 and dynamically cured 40/60 NR/EV A blends. Ln the two cases, the influences of NR-g-PDMMMP grafting rates (i. E. , 71, 80, 89, and 95 %) and of loading level in compatibilizer (i. E. , 0, 1,3,5,7,9,12, and 15 wt% compared to NR) on rheological, dynamical, mechanical, morphological, and thermal properties, were studied. The best compatibilization effects were observed with a NR-g-PDMMMP having a grafting rate equal to 80 %, at a loading level of 7 wt% for 50/50 uncured blend and 9 wt% for 40/60 dynamically cured blend. In these conditions, the highest complex viscosity (positive deviation), tensile strength, and elongation at break, as well as the lowest values of tension set and tan d (damping factor), were observed. SEM micrographs of compatibilized blends showed a size decrease of the domains. It was also noted that the thermal stability of NR/EV A blends was improved by incorporating NR-g-PDMMMP
3
BELLOSTA, DECHAVANNE VERONIQUE. "Contribution a l'etude de la reactivite de derives glucidiques vis-a-vis d'organometalliques : nouvelles syntheses stereospecifiques de c-glycosides." Paris 6, 1987. http://www.theses.fr/1987PA066256.
Full textAbstract:
Deux nouvelles methodes de syntheses stereospecifiques de desoxy-2 c-glucosides possedant une fonction ester d'enol sont presentees : - l'addition conjuguee d'organocuprates cyanes sur des hexeno-1 pyrannuloses-3 peracetyles (l'anhydride acetique piegeant l'enolate intermediaire) permet d'obtenir des aryl-alpha -d-c-glycosides. Cette methode est detendue avec succes en serie furannose; - l'arylation de glycals catalysee par des sels de palladium fournit les composes voulus en une seule etape a partir de derives glucidiques commerciaux. L'etude de la configuration des c-glycosides obtenus est effectuee et de nombreuses donnees structurales sont exposees
4
Alvarez, Gonzalez Eleuterio. "Substitution d'ethers et d'alcools allyliques par differents nucleophiles en presence de complexes de nickel(0) : synthese stereoselective des dienes-1,4 a partir des sulfones dieniques avec le chlorure d'isopropylmagnesium en presence de sels de." Paris 6, 1987. http://www.theses.fr/1987PA066064.
Full text
5
EL, JAZOULI MUSTAPHA. "Formation de liaisons carbone-carbone par l'intermediaire des imidothioesters : applications synthethiques." Caen, 1985. http://www.theses.fr/1985CAEN2016.
Full textAbstract:
Apres une etude de la metallation, suivie d'alkylation, de quelques imidothioesters satures, des reactions d'aldolisation dont la selectivite est examinee, sont realisees a partir d'un n-phenyl imidothioester. Les imidothioesters alpha -insatures dont la reactivite vis-a-vis de magnesiens et de lithiens est etudiee sont de bons accepteurs de michael. Par l'intermediaire des alkylthio-enaminates et d'une cetenimine issue de leur decomposition thermique, de nouvelles voies d'acces a des cetones dissymetriques, sont decrites a partir de n-phenyl imidothioesters satures et alpha -insatures. Synthese de cetones terpeniques et d'une pheromone
6
Hsu, Chia-Pi, and 許嘉璧. "Transition Metals Promoted Addition of Alkynyl Aldehyde and Dimethyl Acetal Protecting Reactions of Aldehyde." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/85757446732804987478.
Full textAbstract:
碩士高雄醫學大學
醫藥暨應用化學研究所碩士班
94
We discussed the reactions of a series of alkynyl aldehydes in this thesis. First of all, to find out the best conditions of reductive reaction for 5-phenylpent-4-yanl compound, we change the species of palladium catalysts and base or add various ligands, which have 3-55% yields; when a series of alkynyl aldehydes which have different alkynyl chain and substitution group was employed in the reaction, 6-55% yields was obtained. To our surprise, we discovered that we can used copper(II) chloride and ammonium chloride as reagents with methanol as solvent for the dimethoxy acetal protection group reaction of 5- phenylpent-4-yanl compound in 88% yields. All the reaction is selective for aldehyde in the presence of ketone.
7
Yao, Chihtung, and 姚志通. "VLE And Boiling Point Of Binary System Of Methyl Acetate, Dimethyl Carbonate, Phenyl Acetate And Diphenyl Carbonate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/35492345938724523523.
Full textAbstract:
碩士義守大學
生物技術與化學工程研究所
100
Diphenyl carbonate (diphenyl carbonate, DPC) is an important chemical intermediate, with low toxicity and non-polluting. DPC can undergo a wide range of reactions, such as halogenation, nitration, hydrolysis and aminolysis reactions, to form many organic compounds or synthetic polymers. Recently, it was found that, in polycarbonate production, DPC can be used, instead of phosgene, to react with bisphenol A by melt transesterification to produce polycarbonates. This makes DPC become an economic and environmental potential product worth in industrial applications. Therefore, for the demand of DPC process development, we select three major ingredients in DPC process, methyl acetate, dimethyl carbonate and phenyl acetate, to study the binary vapor-liquid equilibrium system. All VLE experiments in this study have passed the vapor-liquid equilibrium thermodynamic consistency verification. In addition to VLE, the vapor pressure of methyl acetate, dimethyl carbonate and phenyl acetate are measured. Their NRTL parameters for the VLE information are reported as well.
8
Li, Chin-sheng, and 李進勝. "A general method to synthesize triarylmehtanes by titanium(IV) chloride to promote dimethyl acetals and aromatic compounds." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/24484417015763331332.
Full textAbstract:
碩士國立中正大學
化學所
94
We found that the ring opening of the cyclic carbonate in the presence of nucleophilic arenes and titanium tetrachloride to give the corresponding double Friedel-Crafts reaction product in good yields. In continuation with this result, we also found that the acetals are also useful in this double Friedel-Crafts reaction. In general, the reactivity of aromatic dimethyl acetals is much better than those of aliphatic analogues. The acetal is a much better substrate in comparison with its aldehyde in this reaction. The aromatic dimethyl acetals with electron-withdrawing groups afford the desired products in excellent yields. The aromatic dimethyl acetals with electron-donating substituent, such as methyl group, at the para- or ortho-position of the aromatic ring also afford the desired products in reasonable good yields. Although the meta-methoxy-substituted aromatic dimethyl acetals affords the modest yield of the desired product, there is no reactivity of its para-methoxy analogue in this type of reaction. In comparison with 1,4- and 1,3-dimethoxybenzene, the heteroaromatic compounds are less effective in this type of reaction. Interestingly, the heteroaromatic reagents prefer to react with the aromatic aldehydes in the presence of trifluoroacetic acid to give the desired product in reasonable good yields.
9
FENG, CHUN-MIN, and 馮俊敏. "Intermolecular Interactions in Aqueous Dimethyl Sulphoxide and Acetic Acid Probed by High-Pressure FTIR." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/41520119166751362661.
Full textAbstract:
碩士國立東華大學
化學系
91
Abstract The infrared spectra of DMSO/D2O and CH3COOD/D2O were measured under various concentrations and pressure. The frequencies of the C-H stretching vibration bands for DMSO/D2O mixtures increase with increasing the mole fraction of D2O, implying the contraction of the C-H bonds. As the pressure was elevated to 1.5 GPa, the C-H vibrations of DMSO/D2O were altered into four bands at ~2927 cm-1, ~2941 cm-1, ~3007 cm-1, and ~3025 cm-1. Further concentration-dependent studies indicated that the spectral features at ~2941 cm-1 and ~3036 cm-1 arise from pressure-induced C-H---O hydrogen bonding between C-H in DMSO and oxygen atom in D2O. Ab initio calculations were performed, while the calculated results are consistent with the interpretations based on the high-pressure infrared experiments. Analogous to DMSO/D2O, the pressure-dependent studies on CH3COOD/D2O mixtures provide the evidence of the C-H---O hydrogen bonding as the pressure was elevated.
10
TSAI, WAN-CHING, and 蔡宛靜. "A theoretical study of the photoelectron spectra of dimethyl ether, ethyl methyl ether, and acetic acid." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5wvj58.
Full textAbstract:
碩士國立臺中教育大學
科學教育與應用學系碩士在職專班
105
The photoelectron spectra of dimethyl ether, ethyl methyl ether, and acetic acid were studied by theoretical calculations. The equilibrium geometries and harmonic vibrational frequencies of the three molecules and their cations were computed by using the density functional theory (B3LYP and M06-2X functionals) associated with the aug-cc-pVTZ basis set. The Franck-Condon factors were calculated and the photoelectron spectra of the target molecules were simulated. For dimethyl ether and ethyl methyl ether, their Franck-Condon factors were very small due to drastic geometrical changes, and we computed their photoelectron spectra by using the geometries at the saddle point. The energies of the molecules and cations were also calculated by using the CCSD(T) method associated with the basis sets of aug-cc-pVXZ (X = D, T, Q, 5), which were extrapolated to the complete basis set limit in order to obtain the adiabatic ionization energies. The simulated photoelectron spectra of dimethyl ether, ethyl methyl ether, and acetic acid are in agreement with experiments. The calculated ionization energies are also consistent with experimental values, with deviations of -0.093, -0.003, and -0.007 eV for ethyl methyl ether, dimethyl ether and acetic acid, respectively.
11
Yennam, Amulya. "Comparison of first-line therapies for relapsing-remitting multiple sclerosis." Thesis, 2020. https://hdl.handle.net/2144/42214.
Full textAbstract:
Multiple Sclerosis (MS) is a chronic and potentially disabling disease of the central nervous system (CNS) in which the immune system attacks the protective myelin layer that surrounds nerve cells. While the majority of individuals diagnosed with MS initially present with a non-progressive relapsing form of the disease, there is significant risk of eventually transitioning to a more progressive form for which there are few effective treatments. Consequently, early intervention with disease-modifying therapies (DMTs) is essential for effective disease management. Newly diagnosed patients are typically started on one of four first-line therapies (beta interferon, glatiramer acetate, teriflunomide, or dimethyl fumarate). Though there are distinct differences between these treatments in regard to efficacy and safety, there is no uniform standard for making decisions about which to initiate treatment with. This review gives an overview of current first-line MS therapies, and seeks to highlight the lack of comparison data and the gaps in the current understanding of disease management, as well as the need for more comprehensive research in these areas.
12
Wang, Yu-Cheng, and 汪昱成. "The effect of main group metal cations on the low barrier hydrogen bond of 4,5-dimethyl-1H-imidazole and acetate." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/44622805043161555903.
Full textAbstract:
碩士國立清華大學
化學系
96
The possible involvement of low-barrier hydrogen bonds (LBHBs) in enzyme catalysis has attracted wide attention in recent years. The initial proposal of the existence of special short and strong hydrogen bonds (SSHBs) in enzymatic active sites was based on experimental findings of unique physicochemical properties. The character of a LBHB is based on the shape of the potential energy surface that is the hydrogen atom lies in a double minimum potential well with zero-point vibrational energies the same as or above the barrier height, it is a LBHB. When metal ions exist in hydrogen-bonding systems, their interaction will affect the systems directly or indirectly. This thesis reports the theoretical investigation on the effect of main group metal cations on the LBHB of 4,5-dimethyl-1H-imidazole (DMim) and acetate (Ac), and all calculations were done at B3LYP or RMP2 level. The complex [DMim-H-Ac]1�{ is a normal hydrogen-bonding system, and the character of the hydrogen bond will become a LBHB while Li+、Ca2+、Sr2+ or Ba2+ is added to [DMim-H-Ac]1�{ complex. We find the charge transfer from [DMim-H-Ac]1�{ complex to the metal ion is very small by NBO charge analysis. The analysis of the two relative energy surfaces between [M-DMim-H-Ac]Z�y (M=Li+、Na+、K+、Rb+、Cs+、Ca2+、Sr2+、Ba2+) complex and [DMim-H-Ac]1�{ complex constructed by removing metal ions of [M-DMim-H-Ac]Z+ shows that metal ions affect the hydrogen-bonding system by long-distance stabilization. The ability of long-distance stabilization is according to metal ionic size : in the aspect of alkali metal ionic systems : Li+＞Na+＞K+＞Rb+＞Cs+ system； in the aspect of alkaline metal ionic systems : Ca2+＞Sr2+＞Ba2+ system. The most important interaction between the metal ion and [DMim-H-Ac]1�{ complex is coulombic interaction by analyzing the binding energy between the metal ions and [DMim-H-Ac]1�{ complex.
13
Wu, Chia fen, and 吳佳芬. "(1) Synthesis of 2-tetralones by titanium tetrachloride-Promoted cyclization of 4-aryl-2-hydroxybutanal dimethyl acetals.(2) Synthesis of benzocoumarins from 2-tetralones." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77040416790529510687.
Full textAbstract:
碩士國立中正大學
化學所
98
(1) 2-tetralone is useful in synthetic chemistry, it could be used in many kinds of applications, such as precursors of several natural products and their derivatives, starting materials for synthetic compounds with biological activities and other useful properties. So far, it is not safe and efficient Methodologies from the monocyclic aromatic precursor such as the potential carcinogenicity hazards associated with diazo compound and low boling point ethylene as reagent to preapare 2-tetralone. A general and efficient methodology to prepare 2-tetralone derivatives has been developed. We have prepared ?-dimethyl acetal Weinreb amide and then use it to synthesize 2-tetralones via titanium tetrachloride- promoted cyclization of 4-aryl-2- hydroxybutanal dimethyl acetals . (2) The coumarin subunit is used in many kinds of synthetic chemistry, it is found in many natural products displaying diverse biological activities. It’s exist in antifungals, anticoagulants, compounds active against psoraris and carcinogens. So far, the 5,6-benzocoumarin has been synthesized by bicyclic aromatic 2-naphthol as starting material. We have prepared 2-tetralone and further converted it to 5,6-benzocoumarin by three steps. The first step is added methyl ester to form enol from ketone in conjugated system, then in strong acid condition, the hydroxy reacted with propiolic acid to form tricyclic benzocoumarin skeleton then aromatize from alkane by oxidant-DDQ to form 5,6-benzocoumarin.
14
Chen, Ying-Huei, and 陳穎輝. "Infrared Spectroscopy Studies on the Self-Association of 2-Acetyl-3,5- dimethylpyrrole and Ethyl 3,5-dimethyl-1H-pyrrole-2-car-boxylate in Various Solvents." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/50269298678850977661.
Full textAbstract:
碩士國立交通大學
應用化學系碩博士班
99
The self-association of 2-Acetyl-3,5-dimethylpyrrole (ADP) and Ethyl 3,5-dimethyl-1H-pyrrole-2-carboxylate (EDPC) in various solvents have been studied using infra-red spectra. The molar absorption coefficient of N-H stretching for ADP monomer and ADP dimer are obtained from the equation derived from the concentration dependent integrated absorbance of monomer bands and those of dimer bands, respectively. So does the dimerization constant obtained independently from them. The letter offers an opportunity to check the consistency of the determination. As for EDPC, the spectra is found that two N-H bands exist in monomer region. This system is a monomer-dimer self-association accompanying a cis-trans inter-conversion in monomer. Our three linear plots respectively for cis, trans monomer and dimer bands are unable to give the molar absorption coefficients of cis and trans monomer N-H stretching εC, εt and cis-trans interconversion constant K1, dimerization constant K2, except for the molar absorption coefficient of dimer band. To overcome this difficulty, we resort to quantum chemical calculation using PBE1PBE/6-311++G** functional to give the ratioεC/εt. The letter enables us to estimate K1 from the ratio of integrated absorbance At/AC. With K1 known, other parameters K2, εC andεt can be solved. The solvent effect on the frequency shift, band width, band intensity and enthalpy of dimerization are also discussed.
15
Hsieh, Yuan-Che, and 謝沅哲. "Pervaporation of acetic acid/water mixtures through a zeolitic imidazolate frameworks (ZIF-8)/poly(2,6-dimethyl-p-phenylene oxide) mixed matrix composite membranes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/87491578121049684465.
Full textAbstract:
碩士中原大學
化學工程研究所
103
In this study, ZIF-8 was added into a hydrophobic polymer, poly(2,6-dimethyl-p-phenylene oxide), and casted on PAN support membranes to form a mixed matrix composite membranes. The MMCMs was applied to separate 90wt% acetic acid aqueous solution. However, the pervaporation performance have limited by coupling effect between acetic acid and water at room temperature. This problem was solved by increasing operation temperature, because the kinetic energy of molecular was increased at high temperature that could decreased the interaction between water and acetic acid. On the other hand, the PPO polymer was a glassy polymer that the polymer chain cannot move easily at high temperature, so the pervaporation performance still good at high temperature. The pervaporation separation performance was studied by changing the amount of ZIF-8 and heat treatment. The dispersion of ZIF-8 in the PPO active layer was evaluated by FESEM and EDX images to characterize the structure and dispersible. The membrane structure was correlated with the pervaporation performance. In other ways, the physicochemical properties of ZIF-8/PPO mixed matrix composite membranes was characterized by FTIR、TGA、DSC、water contact angle. The pervaporation results show the performance is limited by coupling effect. In research, heat-treated ZIF-8/PPO mixed matrix composite membranes could improve the pervaporation performance. The flux is 112g/m2h and the separation factor is 1491 at best condition 100°C and 30minutes. The permeation rate and water concentration in permeat of ZIF-8/PPO mixed matrix composite membranes both increased with operation temperature increasing. It confirmed that coupling effect can be reduce by high temperature operation.