Esterification Of Anhydride Research Articles

Structure and properties of p‐carboxysuccinanilic polyester resins

AbstractPolyester resins were prepared by the reaction of p‐carboxysuccinanilic acid ethyl ester with ethylene glycol and 1,4‐butenediol. Also, unsaturated polyester resins were prepared by the copolymerization of p‐carboxysuccinanilic acid ethyl ester and maleic anhydride with ethylene glycol, 1,6‐hexanediol, 1,4‐butenediol, and 2‐butyne‐1,4‐diol. All the polyester resins and the copolyesters have been characterized and were found to cure with styrene, except those prepared in the absence of maleic anhydride. The properties of the cured products in the form of films were determined. Infrared and nuclear magnetic resonance (NMR) spectroscopy were used for both qualitative and quantitative analyses of the polyester resins and their hydrolyzate products after curing with styrene.

ChemInform Abstract: Comparison of Methods of Phthalic Anhydride Esterification to Butyl Benzyl Phthalate.

AbstractThe conversion of (I) to (II) with BuOH and PhChzCl is carried out under a range of conditions to establish the optimum procedure.

The preparation of benzoyl esters of phenols and benzoic anhydride by phase-transfer catalysis

The preparation of benzoyl esters of phenols and benzoic anhydride by phase-transfer catalysis

Chemical Effects on Crude Oil Pipeline Pressure Problems

Summary In the surface transportation of crude oils, high flow line pressures are encountered for a number of reasons. Basically these are a function of the rheological and depositional properties of the crude oil under the temperature-profile and shear-rate conditions developed in the system. These problems can be categorized into these areas: paraffin deposition, asphaltene deposition, thixotropic crude oil, turbulent flow transmission, and low-gravity asphaltic-based crude oils. Various laboratory and field tests are used to identify the key features of these problem crudes for identification and chemical treatment purposes. Introduction Pressure problems during the production of crude oil result in considerable trouble and expense to the producer. Ten years' investigation has resulted in substantial progress in identification and chemical treatment of these problem areas. Proper identification of the mechanism causing the pressure increase has resulted in the elimination of many mechanical and chemical misapplications. The net result has been a reduction in costs to operate these problem systems. Each problem area has key features differentiating it from the other causes of high pressures. The tests used to identify these key factors include cloud point, pour point, viscosity, yield value, solubility parameters, pumping studies, and various deposition and removal tests. Comparative testing of chemical additives under simulated field conditions yields valuable data on the relative treating efficiency of various chemical structures. Subsequent field trials clearly demonstrated the value of preliminary laboratory and onsite testing prior to chemical applications. Paraffin Deposition Paraffin deposits consist of a mixture of linear and branched chained hydrocarbons in the range Of C 18 H 38 to C60 H122, generally mixed with other organic and inorganic materials such as crude oil, gums, resins, asphaltic material, salt, sand, and water. The accumulation of paraffin waxes on pipewalls leads to constriction, which effectively reduces the useful diameter of the line. This causes an increase in pumping pressure and/or a decrease in volume throughput. The solubility of paraffin in crude oil depends on the chemical composition of the crude, temperature, and pressure. Paraffin precipitates from the crude oil at an equilibrium temperature and pressure defined as the cloud point. Paraffin deposition takes place by three mechanisms that transport both dissolved and precipitated waxy crystals laterally. When the oil is cooled, a concentration gradient leads to the transport, precipitation, and deposition of wax at the wall by molecular diffusion. Additionally, small particles of previously precipitated wax can be transported laterally by Brownian diffusion and shear dispersion. Wax Deposition Equipment. Paraffin deposition equipment has been described by a number of authors. All make use of a deposition surface cooled under controlled conditions to a temperature below the cloud point and crude oil solution temperature. We use two types of deposition equipment. The first method is a "static cold finger" similar to that outlined by Jorda. This method allows control over the variables of oil-solution temperature, deposition surface, temperature, temperature differential, T, and time. A second method is a "rotating disk apparatus," as described by Eaton and Weeter, which also controls the velocity variable. Fig. 1 is a diagram of the apparatus. This unit consists of four probes, each of which can be set electronically for a specific temperature. Work has been conducted on a variety of synthetically prepared crude oils and stabilized field crude samples. Paraffin Inhibitors. Paraffin inhibitors are polymers capable of crystal distortion or modification during the deposition process. Because of this cocrystallization mechanism, it is necessary to have the chemical in solution above the cloud-point temperature. This prevents or interferes with the molecular diffusion mechanism of deposition. It also modifies the crystal structure of waxes precipitated into small, highly branched structures with low cohesive properties. Three popular crystal modifiers are copolymers in these groups:Group A-copolymer of ethylene vinyl acetate,Group B-copolymer of C18 through C22 methacrylates, andGroup C-copolymer of olefin/maleic anhydride esters. Laboratory Deposition Testing With Rotating Disk Apparatus. A yellow Wasatch crude oil from the Altamont, UT, area was tested for paraffin inhibition. This crude had a pour point of 38 degrees C [100 degrees F] and a cloud point of 66 degrees C [151 degrees F]. Test conditions are shown in Table 1. Additives 1 and 2, both in Group C, were the most active paraffin inhibitors on this crude. JPT P. 779^

Effects of small organic molecules on the cholinergic receptors of the motor endplate.

This paper deals with the effects on the endplate receptors of the electro-osmotic and bath application of compounds which, although lacking pharmacological affinity, mimic the actions caused at much lower concentrations by conventional cholinergic drugs. Small cyclic molecules containing carbonyl, ether, ester, amide, and carboxyl anhydride groups were tested. Lactones, carboxyl anhydrides, cyclic amides, and ketones depolarized the endplate membrane and, in addition, most of them potentiated the depolarizing action of acetylcholine. On the contrary, cyclic ethers behaved as neuromuscular blocking agents. Dioxane, which contains two ether oxygens, caused a marked prolongation of the time course of the potentials elicited by the iontophoretic application of acetylcholine pulses. In some instances the effects of adding the compounds to the bath were different from those observed following local electro-osmotic application.

Studies concerning the antibiotic actinon. Part V. Synthesis of structural analogues of actinonin by the anhydride-ester method.

Studies concerning the antibiotic actinon. Part V. Synthesis of structural analogues of actinonin by the anhydride-ester method.

Cyclic Esters of Phosphorous — Phosphoric Anhydride as a Tool for Studying the “Abnormal” Biphilic Reactivity of PIII—PV Anhydride System

A series of esters of phosphorous-phosphoric anhydride containing cyclic ester groups at one or both phosphorus atoms were prepared. The typical biphilic character of these compounds has been found. Unexpectedly observed lack of reactivity of anhydrides containing cyclic ester groups at trivalent phosphorus atom with respect to diethylphosphoric and acetic acids is the starting point for discussion on the mechanism of acidolysis. Unusual inertness of PIII cyclic esters of phosphorous-phosphoric anhydride towards protic acids is discussed in terms of Hudson’s concept of steric retardation on quaternisation.

Dissolution of Alkyl Vinyl Ether-Maleic Anhydride Copolymers and Ester Derivatives

The dissolution properties of several alkyl vinyl ethermaleic anhydride copolymers and their ethyl, n-propyl, and n-butyl half-and quarter-ester derivatives were studied. An immersion refractometric method was employed to determine the polymer dissolution properties. Rates of polymer dissolution and lag times prior to the initiation of measurable dissolution rates were shown to be dependent upon several variables. The polymer variables studied included polymer molecular weight, degree of esterification, ester chain length, and ether substituent. Other factors studied were pH of the dissolution medium, type of sample (cast films or compressed disks), and inclusion of a plasticizing agent. Each factor was shown to influence the resulting polymer dissolution properties.

Mass spectrometry in structural and stereochemical problems. CCIII. Course of a triple hydrogen migration in esters of trimellitic anhydride

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMass spectrometry in structural and stereochemical problems. CCIII. Course of a triple hydrogen migration in esters of trimellitic anhydrideCarl Djerassi and John CableCite this: J. Am. Chem. Soc. 1971, 93, 16, 3905–3910Publication Date (Print):August 1, 1971Publication History Published online1 May 2002Published inissue 1 August 1971https://doi.org/10.1021/ja00745a014RIGHTS & PERMISSIONSArticle Views140Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (747 KB) Get e-Alerts Get e-Alerts

Acenaphthene I. The preparation of derivatives of 4,5-diamino naphthalic anhydride

The preparation of 5-nitroacenaphthene (2) using several nitrating agents resulted in a product which was found to be contaminated with 20–30% of the 3-nitro isomeride. Separation was accomplished by t.l.c. and the n.m.r. spectra of the isomers are now reported. A new synthesis of 4,5-dinitronaphthalic anhydride (5) and an improved preparation of the dimethyl and diethyl esters of 4-nitronaphthalic anhydride and 5 is described. The esters were converted to the corresponding diamino derivatives by high pressure hydrogen–Pd reduction.

The synthesis of14C‐ and3H‐labeled glycerol ethers

The racemic(14)C-and(3)H-labeled alpha and beta derivatives of octadecyl glycerol ether (batyl alcohol) and of hexadecyl glycerol ether (chimyl alcohol) of high specific activity were synthesized by treating the appropriate alkyl halides with a large excess of the potassium salts of isopropylidene or benzylidene glycerol. By use of the trifluoroacetic anhydride esterification procedure, the labeled diesters of alpha and beta octadecyl and hexadecyl glycerol ethers were prepared. The labeled monoesters of beta octadecyl and of beta hexadecyl glycerol ethers were isolated from the reaction mixtures by silicic acid column chromatography.

3, 6-endoxocyclohexanes and -cyclohexenes. XXV. Some reactions of dimethyl 4,5-(1-benzyl-1, 2, 3-triazoline)-3, 6-endoxohexahydrophthalate

The anhydride and dimethyl ester of 4, 5-(1-benzyl-1, 2, 3-triazoline)-3, 6-endohexahydrophthalic acid, having a triazoline ring with an exo-cis configuration, are synthesized by reaction of benzyl azide with the furan-maleic anhydride adduct. Opening of the triazoline ring under the action of hydrochloric and acetic acids takes place with the separation of nitrogen and formation of the chloro and acetoxy derivatives, respectively, unaccompanied by a Wagner-Meerwein type of rearrangement.

Aspartic acid formation from glycine phosphate

Glycine phosphate anhydride dimerises in aqueous solution to give aspartic acid. The deamination accompanying the aspartylation reaction is optimal at pH 4.8 and vanishes at pH's less than 3 and pH's larger than 7. Aspartylation takes place by the interaction of two glycine phosphate molecules as well as by the interaction of glycine phosphate with glycine liberated in hydrolysis or added beforehand. In the first alternative, aspartyl diphosphate is formed and undergoes further deaminatiion to fumaryl phosphate and then hydrates to malic acid. The second route yields β-monoaspartyl phosphate which does not deaminate. The reactions, which are complicated, rapid and simultaneous, were analysed kinetically. It was found that the hydrolytic constants of glycine phosphate are higher by two or three orders of magnitude than those of simple acid phosphoanhydrides. They reach their minimum at pH 4.8. The aspartylation constants are maximal in the acid range and approach zero at pH larger than 6. The data show that deamination is due to the attack of a proton from the phosphate groups. If the proton is ionized or is substituted by an organic radical no deamination takes place. A reaction mechanism for deamination and aspartylation is proposed on the assumption that the first step is an intramolecular deamination of glycine phosphate to the ester anhydride of glycolic acid, which further attacks a glycine phosphate molecule to give aspartic acid. The mechanism was supported by the study of competitive reactions with HCN and malonic acid which give malononitrile and α,α,β-ethane tricarboxylic acid. The reaction of condensation to peptides was studies and found to be small in the pH range of aspartylation. At pH's larger than 7, a pronouned peptidisation sets in by the interaction of glycine phosphate with free glycine or with higher peptides. This reaction increases rapidly with pH and gives a characteristic distribution of higher polyglycines.

TOSYLATED PEPTIDES AND p-NITROPHENYL ESTERS

The tosyl group causes interference with mixed carbonic anhydride and p-nitrophenyl ester formation in certain instances. Several protected peptide sequences, occurring in the insulin molecule, and some tosylated p-nitrophenyl esters, have been prepared in the course of investigating this interference.

Synthesis of some esters of ?-acetoxy-?,?,?-trichloroethylphosphonic acid

By the reaction of dialkyl esters of α-hydroxyΒ, Β,Β-trichloroethylphosphonic acid and acetic anhydride in the presence of a few drops of sulfuric acid, the dialkyl esters of α-acetoxy-Β,Β,Β-trichloroethylphosphonic acid were obtained in high yields.

Structure of pristimerin, a quinonoid triterpene

4carried out beoause of its antibiotic properties and conspicuous orange colour. Investigations on pristimerin were resumed here when it was found that the roots of Triptervqium reselii Sprague & Takeda, and especially Celastrus striaillosus Nakai were suitable sources for celastrol. The following chemical and WWR evidences allow the recently proposed structure I5 to be extended to the full expression II. Information on the carbocyclic skeleton, especially C, D and E rings, was gained from selenium dehydrogenation of the ester anhydride III' (permanganate oxidation product of pristimerin). The minute amount of product, in the form of its trinitrobenzolate, m.p. 140-148', absorbed at 260, 282,

Kinetics and chemistry of the polycondensation esters of?-amino acids Communication 4. Copolycondensation of glycine ethyl ester and N-carboxyglycine anhydride

1. Copolycondensation of N-carboxyglycine anhydride and glycine ethyl, ester was carried out in the mass and in solution for various relative amounts of monomers. The chemical compositions of the products were studied. 2. Copolycondensation proceeds under conditions of mutual initiation. No N-carboxyglycine or free peptides were detected in the copolycondensation products, but peptide esters and various amounts of piperazinediones were present. 3. It is suggested that the peptide chain grows from the amino end.

Stereochemistry of cyclic compounds Communication 15. Condensation of 2-methoxy-1, 3-butadiene with maleic and citraconic anhydrides and with the methyl esters of fumaric and mesaconic acids

1. A study was made of the condensations of 2-methoxy-l, 3-butadiene with maleic and citraconic anhydrides and with fumaric and mesaconic esters. The corresponding cis- and trans-4-oxo-1, 2-cyclohexanedicarboxylic acids, their anhydrides, and their methyl esters are described. 2. It was shown that, in the condensation of 2-methoxy-1, 3-butadiene with citraconic anhydride and mesaconic ester, mainly para-adducts are formed, and these were characterized by their derivatives.