Alkylene diols

Alkylene diols are also referred to as propanediol carbamates have been used as tranquilizer. Two mportant members of this classification, namely meprobamate and tybamate have been discussed in the Chapter-8 on Muscle Relaxants in this book. 

A number of diphenylmethane derivatives have been synthesized that exhibit antipsychotie activities. 

A few sueh eompounds are deseribed below, namely Pipradrol Captodiame Hydroxyzine Benactyzine  

It is synthesized by Grignard reaction of phenyl-2-pyridyl ketone with phenyl magnesium bromide followed by catalytic reduction to get the official compound. 

It is used for the treatment of functional fatigue and various types of depressions. 

---

Two-step synthesis of sugar-containing polyesters by lipase CA catalyst was reported (Scheme 13)." Lipase CA catalyzed the condensation of sucrose with an excess of divinyl adipate to produce sucrose 6,6 -O-divinyl adipate, which was reacted with a,oo-alkylene diols by the same catalyst, yielding polyesters containing a sucrose unit in the main chain. This method conveniently affords... 

Some examples of urea foams prepared by the water-isocyanate reaction are as follows. ICI disclosed the foam prepared by the water-isocyanate reaction in the jn-esence of imidazole compounds (137). PRB NV disclosed a foam j epared in the presence of water-soluble saccharide and polyol (139). Bayer AG disclosed a foam prepared by using 1.5 to 50 parts of alkanolamine with water and 100 parts of polyisocyanate (138). Schaum Chemie disclosed foams prepared by using lower alkanols and alkylene diols (140). 

As might be expected, the use of two different alkylene diols in a copolymer largely results in degradation mechanisms which include... 

The environmental and enzymatic degradabOity of copolycarbonates consisting of DAS and DAM and alkylene diols or oligo(ethylene glycols) was investigated [31]. 

Scheme 8.29 Synthesis of the photo-cured poly(diol-tricarballylate) (PDT) bioelastomers from tricarballylic acid, alkylene diols and acryloylchloride.

The photo-cured poly(diol-tricarballylate) (PDT) degradable bioelastomers were prepared based on the polycondensation reaction between tricarballylic acid and alkylene diols such as 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol and 1,12-dodecanediol, followed by acrylation and photo-cross-linking, as shown in Scheme 8.29.The PDT prepolymers, such as poly(l,6-hexane diol-co-tricarballylate) (PHT), poly(l,8-octane diol-co-tricarballylate) (POT), poly(l,10-decane diol-co-tricarballylate) (PDET and poly(l,12-dodecane... 

In this work we wish to report some new results on the dynamic-mechanical behaviour below the glass transition of these supercooled mesophases in thermotropic liquid crystalline polyesters based on bis(4-carbonylphenyl) terephthalate units (HTH) and alkylene diols (C3, C q) or... 

Many similar hydrocarbon duids such as kerosene and other paraffinic and naphthenic mineral oils and vegetable oils such as linseed oil [8001-26-17, com oil, soybean oil [8001-22-7] peanut oil, tall oil [8000-26-4] and castor oil are used as defoamers. Liquid fatty alcohols, acids and esters from other sources and poly(alkylene oxide) derivatives of oils such as ethoxylated rosin oil [68140-17-0] are also used. Organic phosphates (6), such as tributyl phosphate, are valuable defoamers and have particular utiHty in latex paint appHcations. Another important class of hydrocarbon-based defoamer is the acetylenic glycols (7), such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol which are widely used in water-based coatings, agricultural chemicals, and other areas where excellent wetting is needed. 

Polyfunctional fluoronitro alcohois are provided by tlie SRNl reaction of a perfluoroalkyl iodide or alkylene diiodides with the anhydrous lithium salt of 2-nitropropane l,3-diol acetonide. Hydrolysis of the resulting perfluoroalkyl-... 

Rafler el al. [105] applied the two-film model to the mass transfer of different alkane diols in poly(alkylene terephthalate) melts and demonstrated a pressure dependency of the mass-transfer coefficient in experiments at 280 °C in a small 3.6L stirred reactor. They concluded that the mass-transfer coefficient kij is proportional to the reciprocal of the molecular weight of the evaporating molecule. 

Cyclic sulfates can be obtained from diols or polyols in the reaction of the latter with SOCI2 followed by mthenium catalyzed oxidation. These sulfates readily react with LiPPh2 yielding mono- and di-tertiary diphenylphosphines having alkylene sulfate substituents (54-57). This is a highly versatile procedure, since the starting diols are readily available and the products are well soluble and fairly stable in neutral or slightly alkaline aqueous solutions [57,105]. 

Poly(propylene oxide) [25322-69-4] may be abbreviated PPO and copolymers of PO and ethylene oxide (EO) are referred to as EOPO. Diol poly(propylene oxide) is commonly referred to by the common name poly(propylene glycol) (PPG). Propylene oxide [75-56-9] and poly(propylene oxide) and its copolymers, with ethylene oxide, have by far the largest volume and importance in the polyurethane (PUR) and surfactant industry compared to all other polyepoxides. Articles reviewing propylene oxide (1), poly(propylene oxide) (2—4), other poly(alkylene oxides) (4), and polyurethanes (5—7) are cited to lead the interested reader to additional detail not in the scope of this article. 

Very often, the transesterification reaction implies the need for an alkylene or CC (e.g., EC or PC) and an alcohol in the presence of either a homogeneous or heterogeneous acidic or basic catalyst [268], to co-produce dialkyl carbonate and the alkane diol or glycol (Equation 7.30). 

Alkylene CCs have been prepared through the transesterification of appropriate glycols with dialkyl carbonates (usually diethyl or dimethyl carbonate) in the presence of a suitable catalyst. One of the first such examples was the synthesis of six-membered CCs by the transesterification of propane-1,3-diols with DEC catalyzed by sodium ethanolate (Equation 7.31) [289], The reaction was carried out at temperatures between 293 and 333 K, and a conversion yield of 40% was obtained. 

Six-membered alkylene carbonates have also been synthesized by reacting several 1,3-diols with a 15% excess of EC in the presence of titanium(IV) isopro-poxide at 293-323 K and 15-30mmHg [293], In this case, the high-purity (99%) alkylene carbonate was obtained via a short-path distillation at 323-373 K at reduced pressure. Alkylene carbonates have also been obtained by the disproportionation of l,3-bis(alkoxycarbonyloxy)propanes, using colloidal silica or Sn(II) stearate [294]. 

The transesterification of 1,2-diols by reaction with carbonates, both cyclic and linear, produces five-membered alkylene carbonates almost exclusively. A well-known example of this is the reaction of DMC with propene glycol to yield PC [295],... 

The structure of the diol in alkylene terephthalate/PTME terephthalate copolymers has an important effect on the properties of these block copolymers, as evident from the results shown in Tables II, III, and IV. The 50% tetramethylene terephthalate/PTME terephthalate copolymer prepared from 1,4-butanediol (4G) which was previously noted in Table I serves as our reference copolymer for purposes of discussing the effects of changing the structure of the crystallizable ester segments. The outstanding properties of the 4G-based copolymer are ease of synthesis, a rapid rate of crystallization from the melt, a high melting point, and excellent tensile and tear strengths. 

Up to this point the discussion has been concerned with alkylene terephthalate/PTME terephthalate copolymers in which the concentration of alkylene terephthalate and the chemical structure of the alkylene groups have been varied. The next section of this report is concerned with polyether-ester copolymers in which aromatic esters other than terephthalate are used in combination with PTME glycol and various diols. The objective is the same, to correlate changes in copolymer structure with changes in copolymerization results and copolymer properties. Once again the 50% tetramethylene terephthalate/PTME terephthalate copolymer (Tables I and II) with its excellent properties and relative ease of synthesis will be used as the point of reference to which the other polymers will be compared. 

Alkylene Isophthalate/PTME Isophthalate Copolymers. Polyether-ester copolymers having the compositions 50% alkylene isophthalate/ PTME isophthalate were prepared using as diols ethylene glycol (2G),... 

Table VII. 50% Alkylene 4,4 -Biphenyldicarboxylate/PTME 4,4 -Biphenyldicarboxylate Copolymers—Properties as a Function of Diol Structure...

Alkylene 2,6-Naphthalenedicarboxylate/PTME 2,6-Naphthalene-dicarboxylate Copolymers. Fifty percent alkylene 2,6-naphthalenedicar-boxylate/PTME 2,6-naphthalenedicarboxylate copolymers were prepared using each of the straight-chain, hydroxy-terminated diols from ethylene glycol (2G) to 1,10-decanediol (10G) (Table VIII). In contrast to many of the 50% alkylene terephthalate/PTME terephthalate copolymers of Table II, all of the 2,6-naphthalenedicarboxylate-based copolymers tested exhibit excellent tensile strength and tear strength regardless of the diol used or the melting point of the copolymer. As a consequence of their excellent properties, the 2,6-naphthalenedicarboxylate copolymers have been the subject of several patents (32,33,34). 

Alkylene w-Terphenyl-4,4f -dicarboxylate/PTME w-Terphenyl-4,4"-dicarboxylate Copolymers. Polyether-ester copolymers with the composition 50% alkylene rn-terphenyl-4,4"-dicarboxylate/PTME rn-ter-phenyl-4,4"-dicarboxylate were prepared using as diols 1,3-propanediol (3G) and 1,4-butanediol (4G). Both copolymers exhibit excellent tensile and tear strength as shown in Table IX. They both have very poor resistance to compression set. 

Table IX. 50% Alkylene w-Terphenyl-4,4f -dicarboxylate/PTME w-Terphenyl-4,4/ -dicarboxylate Copolymers °—Properties as a Function of Diol Structure (36)...

---