Abstract: The following steps are conducted for producing a hydrocarbon having a carbon number of at least 2: a coupling step, in which a coupling feed gas containing methane and a gas containing oxygen are supplied to a conveying catalyst bed which is formed by an ascending stream which contains a catalyst, and then methane and oxygen are allowed to react so as to produce a coupling product gas; a catalyst separation step for separating the catalyst from the coupling product gas; and a catalyst feedback step for feeding back the thus-separated catalyst to the coupling step. Accordingly, the reaction system does not accumulate excessive heat, the combustion reaction as a side reaction is hindered, and the selectivity of the coupling reaction is enhanced. In addition, the yield of the hydrocarbon having a carbon number of at least 2 is improved.

Abstract: Methods for reducing nitrate nitrogen and oxalic acid contents in plants, each of which comprises applying 5-aminolevulinic acid, a salt thereof or a mixture thereof. Nitrate nitrogen and oxalic acid contents in plants having high nitrate nitrogen and oxalic acid contents can be reduced effectively and easily.