Alcohols condensation

These reversible reactions are cataly2ed by bases or acids, such as 2iac chloride and aluminum isopropoxide, or by anion-exchange resias. Ultrasonic vibrations improve the reaction rate and yield. Reaction of aromatic aldehydes or ketones with nitroparaffins yields either the nitro alcohol or the nitro olefin, depending on the catalyst. Conjugated unsaturated aldehydes or ketones and nitroparaffins (Michael addition) yield nitro-substituted carbonyl compounds rather than nitro alcohols. Condensation with keto esters gives the substituted nitro alcohols (37) keto aldehydes react preferentially at the aldehyde function. 

Alcohols condense with carboxylic acids to form esters. 

Nylon was the first commercial polymer to make a substantial impact on the textile industry, but polyesters now comprise the largest segment of the market for synthetic fibers. In fact, polyesters account for 40% of the more than 4 billion kilograms of synthetic fibers produced in the United States each year. The leading polyester, by far, is poly(ethylene terephthalate), or PET. This polymer is made from terephthalic acid and ethylene glycol in an acid -alcohol condensation reaction ... 

Conjugate addition of methanol to a,/l-unsaturated carbonyl compounds forms a new carbon-oxygen bond to yield valuable ethers (Scheme 26). Kabashima et al. (12) reported the conjugate addition of methanol to 3-buten-2-one on alkaline oxides, hydroxides, and carbonates at a temperature of 273 K. The activities of the catalyst follow the order alkaline earth metal oxides > alkaline earth metal hydroxides > alkaline earth metal carbonates. All alkaline earth metal oxides exhibited high catalytic activities and, as in alcohol condensations and nitroaldol reactions, their catalytic activities were not much affected by exposure to CO2 and air. 

Hydrogenation of benzaldehyde yields benzyl alcohol, condensation with aliphatic aldehydes leads to additional fragrance substances or their unsaturated intermediates. Unsaturated araliphatic acids are obtained through the Perkin reaction, for example, the reaction with acetic anhydride to give cinnamic acid. 

The catalyst must activate three reaction steps Dehydrogenadon of the alcohol, condensation of the aniline with the carbonyl compound produced and hydrogenation of the resulting imine to the desired N-alkylaniline. In the vapor phase the hydrogenation step is the most difficult to achieve under our reaction conditions. 

A propargylic alcohol is selectively oxidized with active M11O2 in the presence of a primary aliphatic amine. The resulting alcohol condenses with the amine, thanks to the action of the added molecular sieves as dehydrating agent, leading to the formation of an imine in a very... 

Esters , lactones.4 In the presence of this catalyst, primary alcohols condense oxidatively to form esters. 

Wherever possible, the soaps and surfactants were added to the natural rubber latex as dilute aqueous solutions. The cases where this was not possible were (a) ethylene oxide-fatty alcohol condensates of low ethylene oxide fatty alcohol mole ratio, and (b) sparingly-soluble fatty-acid soaps such as lithium laurate and calcium soaps. The former were added as pastes with water, the latter as dry powders. In all cases, the latex samples were allowed to mature for about three days at room temperature before their mechanical stabilities were determined. This allowed some opportunity for the attainment of adsorption equilibrium. 

Effects of ethylene oxide-fatty alcohol condensates upon the mechanical and chemical stability of natural rubber latex (10)... 

The results summarised in Figure 7 show that small additions of ethylene oxide-fatty alcohol condensates to natural rubber latex generally cause the mechanical stability of the latex to fall. This phenomenon is attributed to the displacement of adsorbed proteinaceous molecules by the condensate molecules. Although the latter are more surface active than the former, they are presumably less effective in conferring mechanical stability upon the rubber particles, perhaps because, unlike the proteinaceous molecules, they are not ionised. 

Figure 7. Effect of added ethylene oxide-fatty alcohol condensates upon mechanical stability of natural rubber latex ( 0). Levels of condensate are expressed in parts by weight. Numbers appended to curves indicate overall mole ratio ethylene oxide fatty alcohol in condensate.

MST of latex in absence of ethylene oxide-fatty alcohol condensate 970 440 499 374... 

Cyclic Acetals Formation of an acetal using a diol as the alcohol gives a cyclic acetal. Cyclic acetals often have more favorable equilibrium constants, since there is a smaller entropy loss when two molecules (a ketone and a diol) condense than when three molecules (a ketone and two molecules of an alcohol) condense. Ethylene glycol is often used to make cyclic acetals its acetals are called ethylene acetals (or ethylene ketals). 

Ans. (a) Hydroformylation of ethylene, followed by alcohol condensation, followed by hydrogenation (b) hydroformylation followed by hydrogenation (c) hydroformylation followed by oxidation (d) hydroformylation followed by carbonylation. 

The off-gas from a chloral production unit contains 15 vol % Cl 75 vol % HC1, and 10 vol % EtCl2. This gas is produced at a rate of 150 cfm based on 70°F and 2 psig. It has been proposed to recover part of the Cl, by absorption and reaction in a partially chlorinated alcohol (PCA). The off-gas is to pass continuously through a packed absorption tower counter-current to the PCA, where Cl, is absorbed and partially reacts with the PCA. The gas leaving the top of the tower passes through an alcohol condenser and thence to an existing HC1 recovery unit. 

A similar study was performed on the formation of nano crystalline HA in nonionic surfactant emulsions [163]. Instead of using NP-5/NP-9 surfactant, KB6ZA (nonionic surfactant which is a lauryl alcohol condensed with an average of 6 mol of oxyethylene oxide) was used together with petroleum ether as the oil phase to prepare HA powder in an 0/W emulsion system. One of the very apparent advantages of using 0/W emulsion over W/0 microemulsion is... 

Cetylstearyl alcohol condensed with 50 moles of ethylene oxide. 

A 200-ml. two-necked flask is fitted with an efficient Dry Ice-isopropyl alcohol condenser connected to a soda-lime tube, a magnetic stirrer, and a gas inlet tube. Isopropyl alcohol and Dry Ice are added to the condenser while the flask and condenser are flushed with dry nitrogen. The flask is immersed in a Dry Ice-isopropyl alcohol bath, and a vigorous stream of dry ammonia is introduced into the system. When about 80 ml. of liquid ammonia is condensed, the gas inlet tube is replaced with a ground-glass stopper. The cooling bath is removed, stirring is started, and 5.1 g. (0.020 mole) of l,2-bis(w-butylthio)benzene (Note 1) is quickly introduced (Note 2). 

Alkenes and alcohols condense with nitriles under drastic acidic conditions. In most cases sulfuric acid is used either neat or with solvents such as acetic acid. In liquid hydrogen fluoride containing defined amounts of water, nitriles react with linear or branched alkenes to form amides in good yields. Treatment of allylsilanes and allylstannanes with thallium(III) salts in acetonitrile activates Ae alkene for nucleophilic attack of the nitrile group. The generated nitrilium cation (equation 23) is hydrolyzed to the corresponding )V-allylamide. ... 

---