Synthesis of Model, High Molecular Weight Peptides by the Mixed Carbonic-Carboxylic Acid Anhydride Procedure

1954 ◽  
Vol 76 (9) ◽  
pp. 2474-2476 ◽  
Author(s):  
James R. Vaughan ◽  
Joyce A. Eichler
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Acid Anhydride ◽  
Carboxylic Acid Anhydride

THE APPLICATION OF THE ARNDT–EISTERT REACTION TO THE SYNTHESIS OF FATTY ACIDS OF HIGH MOLECULAR WEIGHT

1950 ◽  
Vol 28b (9) ◽  
pp. 556-560 ◽  
Author(s):  
F. A. Vandenheuvel ◽  
P. Yates
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
Carboxylic Acid ◽  
Stearic Acid ◽  
High Molecular Weight ◽  
Efficient Method ◽  
Convenient Method ◽  
Ultraviolet Absorption ◽  
Aliphatic Carboxylic Acid ◽  
Eicosanoic Acid

The Arndt–Eistert reaction offers a convenient method for the synthesis of the higher members of the aliphatic carboxylic acid series. Nonadecanoic acid, eicosanoic acid, and heneicosanoic acid have been prepared successively from stearic acid in good yields. An efficient method of purification of the synthetic products is described. The ultraviolet absorption maxima for some diazoketones derived from the higher members of the aliphatic carboxylic acid series are recorded.

Liquid-liquid extraction of plutonium and americium by cekanoic acid from alkaline medium

2001 ◽  
Vol 89 (2) ◽  
Author(s):  
K. V. Chetty ◽  
V. Sagar ◽  
R. Swarup
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Alkaline Medium ◽  
Distribution Ratio ◽  
Liquid Extraction ◽  
Liquid Liquid Extraction ◽  
Carbonate Medium ◽  
D Values

Liquid-liquid extraction studies of plutonium and americium from aqueous carbonate medium using a high molecular weight carboxylic acid namely cekanoic acid in different diluents has been carried out. The distribution ratio (D) values for Pu(IV) and Am(III) under various parameters such as concentration of extractant, Na

Preparation and Characterization of Poly (Acrylonitrile-co-1-Acryloylpyrrolidine- 2-Carboxylic Acid) with High Molecular Weight

2013 ◽  
Vol 52 (9) ◽  
pp. 1298-1308 ◽  
Author(s):  
Guolei Zhang ◽  
Lingling Chen ◽  
Leilei Qiu ◽  
Xiaodong Xu ◽  
Jing Feng
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Poly Acrylonitrile

Indole N-carbonyl compounds: preparation and coupling of indole-1-carboxylic acid anhydride

1987 ◽  
Vol 52 (17) ◽  
pp. 3934-3936 ◽  
Author(s):  
Dale L. Boger ◽  
Mona Patel
Keyword(s):  
Carboxylic Acid ◽  
Carbonyl Compounds ◽  
Acid Anhydride ◽  
Carboxylic Acid Anhydride

Reactions of Coinage Metal Salts with a Mixed Sulfonic/Carboxylic Acid Anhydride

2007 ◽  
Vol 633 (13-14) ◽  
pp. 2431-2434 ◽  
Author(s):  
Weifeng Shi ◽  
Le Zhang ◽  
Maryam Shafaei-Fallah ◽  
Alexander Rothenberger
Keyword(s):  
Carboxylic Acid ◽  
Acid Anhydride ◽  
Metal Salts ◽  
Coinage Metal ◽  
Carboxylic Acid Anhydride

Hydrazines as Rubber Softeners

1936 ◽  
Vol 9 (2) ◽  
pp. 339-349
Author(s):  
I. Williams ◽  
C. C. Smith
Keyword(s):  
Molecular Weight ◽  
Power Consumption ◽  
Organic Acid ◽  
High Molecular Weight ◽  
Lead Dioxide ◽  
Soft Materials ◽  
Mechanical Efficiency ◽  
Petroleum Products ◽  
Acid Anhydride ◽  
Uniform Manner

Abstract THE process of softening rubber has received much less study than its importance deserves. Since the method of softening rubber by mastication was devised by Hancock, the greatest advances have been in the introduction of machines of greater mechanical efficiency and greater capacity. Prior to 1920 the effect of such variables as temperature was little understood. Long and inefficient periods of milling at high temperatures were common. In case milling did not produce the required plasticity, recourse was had to the addition of oils, resins, and other soft materials sometimes in considerable amounts. Such conditions have not yet entirely disappeared. Various methods have recently been proposed for plasticizing rubber in a more uniform manner and with less power consumption. Worthington and Hyde (24) softened rubber by heating it in a nonoxidizing atmosphere. Bradley and Ferrettie (1) concluded that the rubber should be water-soaked before it is heated and should be kept wet during the process. Tuley (21) patented the process of softening rubber by the addition of lead dioxide during the period of mastication, and Gerke (7) used a mixture of lead dioxide with an organic acid anhydride. Cruikshank (4) proposed the use of solvents containing alcohols of high molecular weight or sulfonated petroleum products as mastication assistants. According to Martin (10) the addition of nitrites to the latex before coagulation produces rubber of superior plasticity. Rubber softened by heating in an oxidizing atmosphere according to the method of Unger and Schidrowitz (22) has recently become a commercial product.

scholarly journals High molecular weight of polylactic acid (PLA): A Review on the effect of initiator

2021 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Norliza Ibrahim ◽  
Anis Nuranisya Shamsuddin
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
High Molecular Weight ◽  
Polylactic Acid ◽  
Ring Opening ◽  
Functional Group ◽  
Nitrogen Atmosphere ◽  
The Other ◽  
Hydroxyl Group ◽  
Aliphatic Polyester

This article reviews various initiator used to synthesize high molecular weight (MW >10,000 g/mol) of polylactic acid (PLA) through ring-opening polymerisation (ROP) of lactide. ROP has been chosen as the best method in producing PLA. On the other hand, stannous octoate (Sn(Oct)2) has been reported as the best catalyst used for ROP method. Many researchers have studied that polymerisation rate with the presence of only Sn(Oct)2 as catalyst is slow compared to polymerisation of lactide with the presence of initiator. An initiator is also favourable in producing high molecular weight of PLA as it can initiate the synthesis of PLA. Therefore, this review focus on ROP method catalysed by Sn(Oct)2 using different solvent as initiator. Among groups of initiators being reviewed are hydroxyl, carboxylic acid, aldehyde, aliphatic polyester and organophosphorus compound. Most of the studies applied in nitrogen atmosphere with a temperature range of 125 to 200 °C, while only one study in vacuum condition. Duration of the polymerisation time is between 1 to 24 hours. Based on the review, alcohol (hydroxyl group initiator) has been reported as the best initiator to produce high molecular weight of PLA. This functional group act as co-initiator molecule that reacts with Sn(Oct)2, forming the initiating stannous alkoxide linkage. The linkage is necessary to propagate monomer addition and hence increase the MW. 

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