Tetramethylene acid

Butanediol. 1,4-Butanediol [110-63-4] tetramethylene glycol, 1,4-butylene glycol, was first prepared in 1890 by acid hydrolysis of N,]S3-dinitro-l,4-butanediamine (117). Other early preparations were by reduction of succinaldehyde (118) or succinic esters (119) and by saponification of the diacetate prepared from 1,4-dihalobutanes (120). Catalytic hydrogenation of butynediol, now the principal commercial route, was first described in 1910 (121). Other processes used for commercial manufacture are described in the section on Manufacture. Physical properties of butanediol are Hsted in Table 2. 

Tetrahydrofuran is polymerized to poly(tetramethylene glycol) with fuming sulfuric acid and potassium biduoride (29). 

Nitrations can be performed in homogeneous media, using tetramethylene sulfone or nitromethane (nitroethane) as solvent. A large variety of aromatic compounds have been nitrated with nitronium salts in excellent yields in nonaqueous media. Sensitive compounds, otherwise easily hydroly2ed or oxidized by nitric acid, can be nitrated without secondary effects. Nitration of aromatic compounds is considered an irreversible reaction. However, the reversibihty of the reaction has been demonstrated in some cases, eg, 9-nitroanthracene, as well as pentamethylnitrobenzene transnitrate benzene, toluene, and mesitylene in the presence of superacids (158) (see Nitration). 

A protonic acid derived from a suitable or desired anion would seem to be an ideal initiator, especially if the desired end product is a poly(tetramethylene oxide) glycol. There are, however, a number of drawbacks. The protonated THF, ie, the secondary oxonium ion, is less reactive than the propagating tertiary oxonium ion. This results in a slow initiation process. Also, in the case of several of the readily available acids, eg, CF SO H, FSO H, HCIO4, and H2SO4, there is an ion—ester equiUbrium with the counterion, which further reduces the concentration of the much more reactive ionic species. The reaction is illustrated for CF SO counterion as follows ... 

THE can be polymerized by many strongly acidic catalysts, but not all of them produce the requked bitimctional polyether glycol with a minimum of by-products. Several large-scale commercial polymerization processes are based on fluorosulfonic acid, HESO, catalysis, which meets all these requkements. The catalyst is added to THE at low temperatures and an exothermic polymerization occurs readily. The polymerization products are poly(tetramethylene ether) chains with sulfate ester groups (8). 

Many other polymerization processes have been patented, but only some of them appear to be developed or under development ia 1996. One large-scale process uses an acid montmorrillonite clay and acetic anhydride (209) another process uses strong perfiuorosulfonic acid reski catalysts (170,210). The polymerization product ia these processes is a poly(tetramethylene ether) with acetate end groups, which have to be removed by alkaline hydrolysis (211) or hydrogenolysis (212). If necessary, the product is then neutralized, eg, with phosphoric acid (213), and the salts removed by filtration. Instead of montmorrillonite clay, other acidic catalysts can be used, such as EuUer s earth or zeoHtes (214—216). 

Polyether Polyols. Polyether polyols are addition products derived from cyclic ethers (Table 4). The alkylene oxide polymerisation is usually initiated by alkah hydroxides, especially potassium hydroxide. In the base-catalysed polymerisation of propylene oxide, some rearrangement occurs to give aHyl alcohol. Further reaction of aHyl alcohol with propylene oxide produces a monofunctional alcohol. Therefore, polyether polyols derived from propylene oxide are not truly diftmctional. By using sine hexacyano cobaltate as catalyst, a more diftmctional polyol is obtained (20). Olin has introduced the diftmctional polyether polyols under the trade name POLY-L. Trichlorobutylene oxide-derived polyether polyols are useful as reactive fire retardants. Poly(tetramethylene glycol) (PTMG) is produced in the acid-catalysed homopolymerisation of tetrahydrofuran. Copolymers derived from tetrahydrofuran and ethylene oxide are also produced. 

Perfluoro(tetramethylene) sulfiUmine is easily oxidized to a sulfoximme by m-chloroperoxybenzoic acid [773] (equation 103)... 

As normally polymerized, PVF melts between IH5 and 210 °C and contains 12 18% inverted monomer units ft is normally considered a thermoplastic, but because of its instability above its melting point, it cannot be processed by conventional thermoplastic techniques Instead it is generally extruded into films in a solvent swollen (organosol) form and the solvent is subsequently evaporated and recovered Such films can be onented further to achieve specific mechanical properties PVF films are exceptionally weather and radiabon resistant considenng their modest fluonne content PVF is insoluble below 100 °C but, at higher temperatures, it dissolves in polar solvents like amides, ketones, tetramethylene sulfone, and tetramethylurea Resistance to acids and bases at room temperature IS good [1, 29 ... 

These compounds yield, on hydrolysis, the free acids, which, like all acids containing two carbo.xyl groups attached to the same carbon atom, lose COj on heating. Thus, ethyl malonic acid yields butyric acid. In this way the synthesis of monobasic acids may be readily effected. Malonic ester, moreover, may be used in the preparation of cyclic compounds as well as of tetrabasic and also dibasic acids of the malonic acid series ( Perkin). To give one illustration malonic ester, and ethylene bromide in presence of sodium alcoholate, yield triniethyleiic dicarbo.xylic ester and tetramethylene tetracarbo.xylic ester. The first reaction takes place in two steps,... 

The formic acid Is distilled off, and the remainder dissolved in warm benzene and washed with a bicarbonate solution to a neutral reaction. After the benzene has been distilled off, the aminomalonic ester xylidide is obtained. This Is treated with an equal quantity of sodium ethylate and boiled with twice the theoretical quantity of tetramethylene bromide in absolute alcohol. 

After 6 hours of boiling, the sodium bromide formed is separated, and the mixture Is steam-distilled in order to remove the excess of tetramethylene bromide. The remaining oil, which mainly consists of delta-bromobutylaminomalonic ester xylidide is separated from the water and boiled with 3 parts of concentrated hydrochloric acid for 3 hours. Thereafter carbonfiltering and evaporation to dryness under vacuum takes place. The residue is dissolved in water, and the pH adjusted with sodium hydroxide to 5.5. The solution is extracted twice with ether, and the water is made strongly alkaline with sodium hydroxide. 

Dimethoxybenzoic acid Tetramethylene dichloride p-Methoxyphenyl acetone Ethylamine... 

An MPI with lower active oxygen concentration was synthesized by inserting the esters of triethylenediol and tetramethylene- or heptamethylenedicarboxylic acid to the chain [25,26]- This MPI shows improved safety against shock and higher solubility to vinyl monomers. 

Peroxybenzoic Acid, p-Nitrol, 1,4,4-Tetramethyl-tetramethylene ester. See 2,5-Bis(p-nitrobenz-oylperoxy-2,5-Dimethylhexane in Vol 2, B135-R... 

In the course of this study, the authors determined /Lvalues for dibenzyl, methyl phenyl, methyl p-nitrophenyl, di-p-tolyl, di-isopropyl and tetramethylene sulphoxides and for diethyl, dipropyl and dibutyl sulphites. The /Lscales are applied to the various reactions or the spectral measurements. The /Lscales have been divided into either family-dependent (FD) types, which means two or more compounds can share the same /Lscale, family-independent (FI) types. Consequently, a variety of /Lscales are now available for various families of the bases, including 29 aldehydes and ketones, 17 carboxylic amides and ureas, 14 carboxylic acids esters, 4 acyl halides, 5 nitriles, 10 ethers, 16 phosphine oxides, 12 sulphinyl compounds, 15 pyridines and pyrimidines, 16 sp3 hybridized amines and 10 alcohols. The enthalpies of formation of the hydrogen bond of 4-fluorophenol with both sulphoxides and phosphine oxides and related derivatives fit the empirical equation 18, where the standard deviation is y = 0.983. Several averaged scales are shown in Table 1588. 

Poly(tetramethylene oxide) polyols (see Scheme 4.4) are a special class of polyethers syndiesized via acid-catalyzed ring-opening polymerization of tetrahy-drofuran. Although less susceptible to side reactions, the synthesis of these C4 ethers is less flexible in terms of product composition and structure. Thus, because of diis syndietic route, only two-functional glycols are available and copolymers are not readily available. Molecular weights of commercial C4 glycols range up to about 3000 g/m. 

All these steps proceed to afford free or N -substituted crystalline cytidines 6 in high yields [11] (cf. the preparation of N (tetramethylene)cytidine 6b in 95.4% yield in Section 1.1.). This simple one-pot reaction is also very easy to perform on a technical scale, as are the subsequently discussed analogous silylation-aminations of purine nucleosides and other hydroxy-N-heterocycles (cf. Sections 4.2.4 and 4.2.5). The concept of silylation-activation while simultaneously protecting hydroxyl groups in alcohols, phenols, or phosphoric acids by silylation was subsequently rediscovered and appropriately termed transient protection [16-18]. 

Hexamethylene glycol, HO(CH2)gOH. Use 60 g. of sodium, 81 g. of diethyl adipate (Sections 111,99 and Ill.lOO) and 600 ml. of super- y ethyl alcohol. All other experimental details, including amounts of water, hydrochloric acid and potassium carbonate, are identical with those for Tetramethylene Glycol. The yield of hexamethylene glycol, b.p. 146-149717 mm., is 30 g. The glycol may also be isolated by continuous extraction with ether or benzene. 

Firstly, catheter sample 1 was dissolved in deuterated trifluoroacetic acid, and the solution analyzed by [H NMR spectroscopy. The [H NMR spectrum of the sample is shown in Figure 52. The peaks at 1.16 ppm, 2.56 ppm, and 3.40 ppm are consistent with a polyamide-12 (PA-12) structure. The signal at 3.58 ppm can be attributed to tetramethylene glycol (TMG) protons adjacent to the ether linkages. The signal at 1.60 ppm is composed of overlapping resonances from both components. The smaller peaks are most likely due to polymer end groups or protons at the junction of two blocks the material is an amide-ether block... 

A microgel of a dz = 76 nm which is suitable for coupling with proteins, can be prepared by emulsion terpolymerization of NjAT -tetramethylene bisacrylamide, n-hexylmethacrylamide and propene acid amide-N-(4-methyl-2-butyl-1,3-diox-olane) [291 ]. The diameter of these microgels may be varied by the concentration of the emulsifier (Fig. 57) and is rather uniform. As the CMC of this system is about 2.5 X10"3 mol SDS/1, it may be assumed that below this value the copolymerization essentially takes place in the monomer droplets, whereas at higher concentrations of SDS preferentially the monomers in micelles are polymerized. 

Starting materials which are only sparingly soluble in water may require solvents that are either partially or entirely organic. Diazotization can either be carried out as usual with an aqueous sodium nitrite solution, or alternatively with nitrosylsul-furic acid or an organic nitrite. Appropriate solvents must be stable to the reactants. Examples include aromatic hydrocarbons, chlorohydrocarbons, glycol ethers, nitriles, esters, and dipolar aprotic solvents, such as dimethyl formamide, dimethyl sulfone, tetramethylene sulfone, tetramethyl urea, and N-methylpyrroli-done. 

PTT is made by the melt polycondensation of PDO with either terephthalic acid or dimethyl terephthalate. The chemical structure is shown in Figure 11.1. It is also called 3GT in the polyester industry, with G and T standing for glycol and terephthalate, respectively. The number preceding G stands for the number of methylene units in the glycol moiety. In the literature, polypropylene terephthalate) (PPT) is also frequently encountered however, this nomenclature does not distinguish whether the glycol moiety is made from a branched 1,2-propanediol or a linear 1,3-propanediol. Another abbreviation sometimes used in the literature is PTMT, which could be confused with poly(tetramethylene terephthalate),... 

Hexahydropyrido[l,2-6]pyridazin-8-ones 178 and a 2,3-tetramethylene derivative were formed on the intramolecular cycloaddition of 177, formed in situ by dehalogenation of hydrazones of the hex-5-enoic acid derivatives 176 [87JCS(P1)2511]. Intramolecular cycloaddition of hydrazones 179 in... 

The hard-soft block copolymer approach employed to produce segmental PUs (Section 7.6) has also been used with polyesters, with the hard block formed from 1,4-butadienediol and terephthalic acid while the soft block is provided by oligomeric (approximate molecular weight of 2000 Da) poly(tetramethylene glycol) and is sold under the trade name Hytrel. 

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