Padma S. Vankar

Dyeing of cotton, wool and silk with extract of Allium cepa

– The purpose of this paper is to evaluate the efficiency of dyeing on cotton wool and silk fabrics with natural dye obtained from kitchen waste of dry skin extract of Allium cepa., – The dry skin of onion produces natural dye which has been used for dyeing textiles. In the present study, innovative dyeing with onion has been shown to give good dyeing results. Pretreatment with 2 per cent metal mordant and using 5 per cent of plant extract (owf) was found to be optimum and showed very good fastness properties for cotton, wool and silk dyed fabrics. For effective natural dyeing with dry skin extract of Allium cepa, conventional method of dyeing was carried out using metal mordants. The purpose of using this source was with an idea to produce value addition dyed product from kitchen waste as the dye has very good potential of uptake, adherence to the fabric and has good wash and light fastnesses. Results show very attractive hue colours., – The preference of using easily and cheaply available material for dyeing by conventional dyeing lowers the cost of natural dyeing and enhances resource productivity and as a result, reduces waste. This makes onion scale one of the easily available materials for natural dyeing industry., – Although metal mordanting with copper sulphate and potassium dichromate are not ecofriendly but we have used only 2 per cent of these metal salts to prepare different shades with dry scales of Allium cepa extract., – The method developed for natural dyeing of cotton, silk and wool fabrics using skin extract of allium in conjunction with metal mordanting has shown very deep coloration. The stepwise dyeing of cotton fabric with metal mordant by the natural dye Allium cepa showed that the stepwise dyeing process gave very good result. The dye uptake in case of stepwise dyeing was from 65‐68 per cent in the case of cotton, 70‐74 per cent in silk and 78‐82 per cent in wool with different mordants., – The method developed for natural dyeing of cotton, silk and wool fabrics using skin extract of allium in conjunction with metal mordanting has shown marked improvement in terms of dye adherence and fastness properties and can thus be recommended for industrial application.

Studies in Lewis acid and LiClO4 (or Nafion-H) catalysed ionic Diels-Alder reactions of chiral and achiral olefinic acetals respectively☆☆☆

Abstract Chiral olefinic acetals derived from crotonaldehyde undergo ionic Diels-Alder reaction giving the corresponding cycloadducts in moderate to good diastereoselectivities. A variety of achiral olefinic acetals react with isoprene and cyclopentadiene to form the cycloadducts in good to excellent yields when catalysed by 4M LiClO4 in nitromethane or by Nafion-H in dichloromethane.

A Mild and Selective Method for the Conversion of Nitroalkanes to Carbonyl Compounds

Abstract Nef reaction is one of the most commonly used method for the conversion of nitroalkanes to carbnyl coacpunds. It was found that the salt of primary nitroparaffins are transformed in to aldehydes and those of secondary nitro coapounda into ketones, when they are treated with aqueous acid.1 ernate procedures for effecting this transformation have been reported.2 cedures appeared in the literature after the work of Sehecter and Williams2a using potassium penaanganate as the axidant. Recently, Kornblum and Steliou reported useful modif icationa of the original permanganate proeedtlre.2a A number of modifications and alt In fact most of the modified pro-3 Although the yield of the carbony1 compounds is generally high i n simple nitroalkanes Using the modi-fied permanganate procedures, the yield drops down considerably in the case of substrates containing Other oxidizable functional groups like carbon-carbon double bonds and hydroxyl groups. Hence a need still exists for the development of a methodolog...

Comparative Study of Total Phenol, Flavonoid Contents and Antioxidant Activity in Canna indica and Hibiscus rosa sinensis: Prospective Natural Food Dyes

In the present study the comparative data of total phenol and total flavonoid contents along with antioxidant activity were assessed in native Canna indica. Total phenolic contents were analyzed by a Folin-Ciocalteu reagent and antioxidant activity was analyzed by DPPH assay and TEAC assay, in crude methanolic extracts of red, yellow varieties of Canna indica and red variety of Hibiscus rosa sinensis. DPPH assay of crude extracts taking pyrogallol as standard show that fresh red canna extract has best results for radical scavenging. Stability of color content of canna towards pH and its pKa were assessed. Colorimetric analysis of crude extracts showed red canna extract to be the best in terms of its tinctorial strength, a pre-requisite for a food dye. On the basis of the results obtained, red canna flowers were found to serve as a potential source of natural antioxidant and a natural food colorant.

Antifungal textile dyeing withMahonia napaulensis D.C. leaves extract based on its antifungal activity

The antifungal activity of the methanolic extract ofMahonia napaulensis D.C. or Taming (local name) leaves was evaluated with four species of common pathogenic fungi e.g.Colletotrichum capsici (MTCC No. 2071),Leptosphaerulin trifoli (MTCC No. 2328),Alternaria brassicicola (MTCC No. 2102) andHelminthosporium solani (MTCC No. 2075). The present investigation also aims at developing an eco friendly natural antifungal finish from plant extract ofMahonia for textile application. The antifungal textile dyeing was also carried out with aqueous extract of stem and leaves ofMahonia and the dyed fabric was tested against fungal speciesTrichoderma for its antifungal activity in vitro.Mahonia extract showed substantial antifungal activity of 83.33% forLeptosphaerulin trifoli andAlternaria brassicicola by 80 ppm dose in 24 hours and 46% antifungal activity inMahonia dyed pieces in broth againstTrichoderma.

Essential oils and fragrances from natural sources

The study of a perfume includes extraction of scented ingredients from botanicals, behavior of chemical components, and careful blending of scents to achieve the desired composition. Essential oils may be found in roots, flowers, leaves, fruit, seeds or bark of the plant. Growing and harvesting conditions are optimized for the production of the best fragrances.

Palladium catalysed conversion of vinyl bromo allylic alcohols into vinylic carbonyl compounds and oxidation of secondary alcohols to ketones

Abstract A variety of vinyl bromo allylic alcohols are converted into the corresponding vinylic carbonyl compounds and secondary alcohols are oxidised into ketones upon treatment with palladium acetate in the presence of potassium carbonate under the typical Heck reaction conditions.

Natural Dyeing with Black Carrot: New Source for Newer Shades on Silk

Silk dyeing with black carrot or Daucus carota has been attempted for the first time, giving good shades on silk. The colorant responsible for shades of green is primarily anthocyanins, which are more stable over a wider pH range than anthocyanins from other vegetable sources, making it ideal for textile dyeing. Premordanted with metal salts the dyed silk has shown remarkable CIE La*b* values and fastness properties. The K/S of dyed silk swatches increased in the order of reactivity –FeSO4 > SnCl2 > SnCl4 > Alum > CuSO4 > K2Cr2O7. Black carrot can be a potential dyeing source for natural dyeing.

Sulphates for skin preservation—A novel approach to reduce tannery effluent salinity hazards

In tanneries microorganisms are able to find environment suitable for their growth. Raw hide of buffalo and other animals like goat that are economically important, are an ideal source of nutrients for bacterial and fungal growth. In the past, preservatives like sodium chloride provided effective protection to fresh hides however the ill effect of their excessive use was not evaluated. But recently concern over potential ecological hazards has become more deliberate and sodium chloride features lot of disadvantages in agriculture as most of the tannery effluent is flown in agricultural fields in India. After rigorous laboratory experimentation on moisture content, SEM of hide, pure sodium sulphate as well as sodium sulphate in addition with sodium chloride (i.e. 10% w/w and 20% w/w) proved as most preferable option for curing of buffalo hide which gives effective preservation. Pollution load studies put forward sodium sulphate as an effective curing agent for buffalo hide to apply at industrial scale also.

Ultrasound-Assisted Extraction in Different Solvents for Phytochemical Study of Canna indica

Red flowers of Canna indica (Family Cannacece) were extracted in Sonicator with different solvents for the estimation of polyphenols and flavonoids using fresh as well as dry flowers. Antioxidant capacities of L- Ascorbic acid, trolox, pyrogallol and Canna flower extracts were also evaluated based on its ability to scavenge the DPPH radical, results obtained were compared with those of TEAC assay. A good correlation was observed between the two methods. The results showed that acetone extract of fresh flowers contained the highest amount of antioxidant activity 78.33 %, 89.7 mg GAE / g and 51.45 ?MT / g although the yield of the extract in the methanol was highest (34 g / 100 g). Total phenol and flavonoids content (0.96 mg GAE / 100 g) (19.89 mg QE / 100 g) were also evaluated for these extract. This is the first report on the phytochemicals and antioxidant activity from Canna indica flowers particularly for its radical scavenging activity and can be a good source of food additives.