The Chemistry of Sugar-Cane Wax. I. The Nature of Sugar-Cane Wax

1960 ◽  
Vol 13 (2) ◽  
pp. 261 ◽  
Author(s):  
JA Lamberton ◽  
AH Redcliffe
Keyword(s):  
Sugar Cane ◽  
Aldol Condensation ◽  
Conclusive Evidence ◽  
High Yield ◽  
Reduced Pressure ◽  
Polymeric Form ◽  
Cannizzaro Reaction ◽  
Long Chain

Distillation of sugar-cane cuticle wax under reduced pressure gives a high yield of long-chain aldehydes, which are considered to occur in the wax in polymeric form. The products obtained from the wax under normal saponification conditions are apparently produced from the aldehydes by a Cannizzaro reaction, and by aldol condensation with subsequent dehydration. The cuticle wax also contains hydrocarbons and free alcohols and acids, but there is no conclusive evidence for the presence of esters.

Synthesis of long chain alkanes via aldol condensation over modified chitosan catalyst and subsequent hydrodeoxygenation

2021 ◽  
pp. 131368
Author(s):  
Xuelai Zhao ◽  
Song Li ◽  
Yuzhen Hu ◽  
Xinghua Zhang ◽  
Lungang Chen ◽  
...  
Keyword(s):  
Aldol Condensation ◽  
Modified Chitosan ◽  
Long Chain

scholarly journals Do long-chain n-3 fatty acids reduce arterial stiffness? A meta-analysis of randomised controlled trials

2011 ◽  
Vol 106 (7) ◽  
pp. 974-980 ◽  
Author(s):  
Matthew P. Pase ◽  
Natalie A. Grima ◽  
Jerome Sarris
Keyword(s):  
Fatty Acids ◽  
Arterial Stiffness ◽  
Arterial Compliance ◽  
Meta Analysis ◽  
Conclusive Evidence ◽  
Clinical Trial Registries ◽  
Stiffness Reduction ◽  
Sample Characteristics ◽  
Randomised Controlled ◽  
Long Chain

Fish oils, rich in long-chain n-3 PUFA, are known to reduce various risk factors for CVD. However, conclusive evidence regarding the benefits of n-3 on arterial stiffness, a risk factor for CVD, has not yet been established. Consequently, we conducted the first study aimed to quantify the effects of n-3 supplementation on arterial stiffness through meta-analysis. Multiple databases and clinical trial registries were systematically searched up until September 2010 for randomised and controlled adult human clinical trials to investigate the effects of long-chain n-3 fatty acids on arterial stiffness. No limits were set on dosage sizes or sample characteristics. A total of ten n-3 trials met the final inclusion criteria; four using pulse wave velocity (PWV) and six using arterial compliance, measured as capacitive compliance or systemic arterial compliance, as respective outcome measures. Meta-analysis revealed that n-3 was statistically significant in effectively improving both PWV (g = 0·33; 95 % CI 0·12, 0·56; P < 0·01) and arterial compliance (g = 0·48; 95 % CI 0·24, 0·72; P < 0·001). There was no evidence of heterogeneity or publication bias. Results were not influenced by changes in blood pressure, heart rate or BMI. The findings of the present study reveal that supplementation with n-3 offers a scientifically supported means of reducing arterial stiffness. Reduction in arterial stiffness by n-3 may account for some of its purported cardioprotective effects.

High-yield hydrogen production by supercritical water gasification of various feedstocks: Alcohols, glucose, glycerol and long-chain alkanes

2014 ◽  
Vol 92 (10) ◽  
pp. 1834-1844 ◽  
Author(s):  
Ratna F. Susanti ◽  
Laras W. Dianningrum ◽  
Taewoo Yum ◽  
Yunje Kim ◽  
Youn-Woo Lee ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Supercritical Water ◽  
High Yield ◽  
Supercritical Water Gasification ◽  
Long Chain

Supercritical extraction of long chain n-alcohols from sugar cane crude wax

2007 ◽  
Vol 41 (2) ◽  
pp. 267-271 ◽  
Author(s):  
Antonio de Lucas ◽  
Alberto García ◽  
Amaury Alvarez ◽  
Ignacio Gracia
Keyword(s):  
Sugar Cane ◽  
Supercritical Extraction ◽  
Long Chain

scholarly journals The constitution of sulphur vapour

1919 ◽  
Vol 95 (672) ◽  
pp. 484-492 ◽  
Keyword(s):  
Boiling Point ◽  
Diatomic Molecules ◽  
Conclusive Evidence ◽  
The Other ◽  
Molecular Formula ◽  
Reduced Pressure ◽  
Vapour Density ◽  
Temperature And Pressure ◽  
Sulphur Vapour

The constitution of sulphur vapour has been studied by many investigators, the method usually employed being based upon the determination of the density. In 1835 Dumas and Mitscherlich found the vapour density at temperatures near the boiling point to be 6∙56, which corresponds closely with the molecular formula S 6 . Deville and Troost carried out determinations at temperatures ranging from 860°C to 1040°C. and obtained the value 2∙23 which is that required by the formula S 2 . More recently Biltz has shown that below 800°C. the density is greater than is required by the formula S 2 , and at 468°C. becomes 7∙8 which corresponds approximately to the formula S 7 , without any constant value being observed between these temperatures. Bleier and Kohn found that when determinations were made under reduced pressure between 192°C. and 310°C. the density of the vapour gradually rose with increase of pressure and slowly but asymptotically approached the value S 8 . Evidence of the existence of molecules containing eight atoms has also been obtained from an examination of solutions of sulphur. Biltz holds that the value obtained by Dumas and Mitscherlich is only of significance for the conditions of temperature and pressure under which it was determined, and affords no evidence of the presence of hexatomic molecules in the vapour. His view is that only octatomic and diatomic molecules have any existence, the former gradually dissociating into the latter as the temperature is raised until about 900° C., the dissociation of the heavier molecules is complete and the vapour is composed entirely of diatomic molecules. Above this temperature no further change appears to occur. Premier, on the other hand, from a study of the curve representing the change of density with change of pressure considers that it is not unlikely that hexatomic and tetratomic molecules are formed as intermediate pro­ducts of the dissociation of the octatomic molecules. Of this, however, the investigation of the vapour density does not afford any conclusive evidence.

Anhydropenicillin: a key intermediate for the stereocontrolled introduction of the 6-R-hydroxyethyl side chain of the penem and carbapenem antibiotics

1987 ◽  
Vol 65 (9) ◽  
pp. 2179-2181 ◽  
Author(s):  
Alain Martel ◽  
Jean-Paul Daris ◽  
Carol Bachand ◽  
Marcel Menard
Keyword(s):  
Hydroxy Group ◽  
Aldol Condensation ◽  
Reductive Dehalogenation ◽  
High Yield ◽  
Side Chain

Aldol condensation of the magnesium enolate derived from anhydro-6,6-dibromopenicillin with acetaldehyde allows for the stereospecific introduction of a 1-R-hydroxyethyl substituent at C-6. Protection of the hydroxy group followed by reductive dehalogenation provides anhydro-6(α)-[(1-R)-(tert;-butyldimethylsilyloxy)-ethyl]-penicillin, an intermediate in the synthesis of thienamycin. A high yield conversion of this anhydro derivative to (4-R)-acetoxy-(3-S)-[(1-R)-(tert-butyldimethylsilyloxy-ethyl]-azetidin-2-one (5) is also reported.

scholarly journals Facile Condensation of Aromatic Aldehydes with Chroman-4-ones and 1-Thiochroman-4-ones Catalysed by Amberlyst-15 under Microwave Irradiation Condition

2011 ◽  
Vol 8 (2) ◽  
pp. 863-869 ◽  
Author(s):  
Tapas K. Mandal ◽  
Rammohan Pal ◽  
Rina Mondal ◽  
Asok K. Mallik
Keyword(s):  
Microwave Irradiation ◽  
Aldol Condensation ◽  
Aromatic Aldehydes ◽  
Solvent Free ◽  
Environmentally Benign ◽  
High Yield ◽  
Irradiation Condition ◽  
Free Condition ◽  
Amberlyst 15 ◽  
Solvent Free Condition

Different aromatic aldehydes and cinnamaldehyde undergo cross-aldol condensation with chroman-4-ones and1-thiochroman-4-ones in the presence of amberlyst-15 under microwave irradiation in solvent free condition to afford rapidly the correspondingE-3-arylidene andE-3-cinnamylidene derivatives, respectively, in high yield. This process is simple, efficient and environmentally benign.

scholarly journals Pemilihan Varietas Tebu Sesuai Lahan Menggunakan Metode Fuzzy Inferensi System Mamdani

2018 ◽  
Author(s):  
Daniel Alfa Puryono
Keyword(s):  
Sugar Cane ◽  
Fuzzy Inference ◽  
Target Selection ◽  
High Yield ◽  
Seed Selection ◽  
Transport Costs ◽  
Inference System ◽  
Sugarcane Varieties ◽  
Sugar Mills ◽  
Selection Of

In line with the government's program to increase the yield and quality in the field of agriculture one of them is able to self-sufficiency. Thus the increase in agriculture cane ranging from seed selection in accordance with the land until the processing of sugar cane into sugar ready for sale with its main partners sugarcane farmers is a must. Indeed there are many varieties of seed cane but there are also many varieties of sugarcane that do not reach the targets with a maximum sugar production because it does not conform with the land at the time of planting, so that farmers suffered losses as well as sugar mills also can not result in the production of sugar in accordance with the target. Selection of sugarcane varieties in accordance with the conditions of land and soil types is very important to improve farm productivity and farm land. Many ways to define the appropriate criteria to obtain varieties with high yield and with a low tonnage in order to produce more sugar at once can reduce transportation costs and cut transport costs. Because sugarcane varieties largely determines the success of the production of sugar in the plant because basically sugar made in the garden, one way of selecting appropriate seeds whith fuzzy logic. This study aims to determine the varieties of sugar cane in accordance with the land by using a model of Mamdani Fuzzy Inference System or often also known as min-max method. Analysis of the system to get the output is done in several steps, namely the establishment of fuzzy sets, Establishment of rules, rules of composition determination, discernment (defuzzification). While the selection of appropriate varieties of sugar cane land based species and varieties of sugarcane, soil, drainage, climate such as rainfall and temperature, sunlight and air speed. The results of this study shows the results obtained proved to be better and more natural. Researchers made this system is expected to help cane farmers and sugar mills in making more accurate decisions to be in recommendations to farmers and overseers field. Because the report is valid and there is no duplication or manipulation of data.

Isopropylidenation of L-arabinose N,N-dimethylhydrazone

1985 ◽  
Vol 50 (9) ◽  
pp. 1994-1999 ◽  
Author(s):  
Miroslav Koóš ◽  
Harry S. Mosher
Keyword(s):  
Sulfuric Acid ◽  
High Yield ◽  
Cannizzaro Reaction ◽  
Branched Chain

Direct isopropylidenation of L-arabinose N,N-dimethylhydrazone (I) was studied. Four major products whose structures were proven were produced in varying ratios depending upon the conditions. 2,2-Dimethoxypropane and sulfuric acid at 20 °C gave a 36% yield of 2,3:4,5-di-O-isopropylidene-L-arabinose N,N-dimethylhydrazone (II). Attempted aldol condensations directly on this hydrazone with paraformaldehyde were unsuccessful. This hydrazone was readily hydrolyzed to the corresponding protected aldehyde VI which underwent an aldol-Cannizzaro reaction to give the branched chain pentitol VII in high yield.

Sign in / Sign up

Export Citation Format

Share Document