Flowering part of Origanum majorana L. was collected from National Botanical Garden of Iran in Aug. 1999 and after confirming by the Herbarium of the Research Institute of Forests and Rangelands, steam distilled for 45 min. to produce an oil of 0.3% yield (based on dry weight of flowers). The oil was analyzed by GC and GC/MS. Twenty-four compounds were identified among which linalyl acetate (26.1%) and sabinene (12.0%) were the major constituents.

The essential oil constituents of the peel and leaf of Citrus aurantiumL. (Rutaceae) grown in the north of Iran, were analyzed by GC and GC/MS. Fourteen components representing 99.6% of the leafoil were identified. The major compounds were linalool (39.4%), linalyl acetate (38.8%) and a-terpineol (7.2%). Twenty constituents consisting 99.4% of the peeloil were identified. The main components were limonene (91.3%), b-myrcene (3.0%) and linalool (1.1%).

Flowering part of Origanum majorana L. cultivated in national botanical garden of Iran was collected in Aug. 1999 and after confirming by the Herbarium of the research institute of forests and rangelands, steam distilled for 45 min. to produce an oil of 0.3% yield (based on dry weight of flowers). The oil was analyzed by GC and GC/MS. Twenty-four compounds were identified, among which linalyl acetate-(26.1 %) and sabinene (12.0%) were the major constituents.

The statistical empirical design is based on the statistical modeling of nonlinear polynomial equation and coding of these equations in the solution polymerization of vinylacetate in a factorial design. The surface calculation considers time, temperature and percent conversion as important factors in this polymerization reaction. In response, the influence of these factors is determined from the polynomial equations. Nonlinear regression is also used to model the hydrolysis of polyvinyl acetate. Variance analysis is used in the study of dispersion of experimental data. The confidence level in this design is reported from total sum of the square and statistical calculations.

Oregano (Origanum vulgare L.), a native plant from Iran, belongs to Lamiaceae family. This species is traditionally utilized as sedative, diuretic, sweater and antiseptic, It is also used to treat of gastrointestinal diseases and constipation. Origanum species are widely used in spice industry. In this study, the essential oil of the aerial parts of a subspecies from this plant namely Origanum vulgare ssp. vulgare was isolated through hydro-distillation following its collection from South region of Chalus in its flowering as well as in seed stages. The extracted essential oils were analyzed through GC and GC/MS systems. Nienteen compounds were identified in the extracted essential oil in the flowering stage which constituted about 99% of the total oil. The latter sample was found to be rich in linalyl acetate (27.2%), g-terpinene (16.5%), 3-octanone (10.9%), b-pinene (8.4%) and carvacrol (6.4%). The 22 identified compounds made up 98.6% of the essential oil in seed stage, carvacrol (23.2%), a-pinene (15.8%), b-pinene (10.7%) and trans-caryophyllene (5.3%) constituted the main compounds. According to the GC/MS results, the monoterpenes were characterized as the most predominant essential oil fraction in either stage. The percentages of the other components of the oils were 16.8 and 5.7 for the plant at flowering and at its seed stages, respectively.