NOVELTY - Manufacturing (P1) rivaroxaban or its salt involves: (i) obtaining an acid addition salt of a 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one, where the acid used to form the acid addition salt is an organic acid; and (ii) reacting the acid addition salt of a 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one obtained in step (i) with the suitable reagents to obtain rivaroxaban or its salt.    USE - For manufacturing rivaroxaban or its salt which is used in pharmaceutical composition for the prevention of venous thromboembolism (VTE) in adult patients undergoing elective hip or knee replacement surgery (all claimed), and for the treatment and/or prevention of thromboembolic disorders e.g. myocardial infarct, angina pectoris (including unstable angina), reocclusions and restenosis after angioplasty or aortocoronary bypass, stroke, transitory ischemic attacks, peripheral arterial occlusion disorders or pulmonary embolisms.    ADVANTAGE - The present process provides rivaroxaban with high yield and purity (preferably 99 wt./wt.%, especially 99.5 wt./wt.% HPLC purity). The present process comprising the use of the organic acid addition salt results is a straightforward reproducible process, which is more environmentally friendly and applicable at industrial scale.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) preparing (P2) pure rivaroxaban involving (a) heating a mixture comprising crude rivaroxaban with at least two organic solvents, where one first solvent is selected from acetic acid, formic acid, N,N-dimethylformamide (DMF) and/or its aqueous mixture (preferably formic acid or its aqueous mixtures), and one second solvent is selected from acetone, acetonitrile, methyl ethyl ketone (MEK) and/or methyl isobutyl ketone (MIBK) (preferably acetone, MEK and/or MIBK), to a temperature higher than 50 degrees C, and b) obtaining pure rivaroxaban by decreasing the temperature of the mixture obtained in step (a) to a temperature 0-30 degrees C, preferably 20-30 degrees C;    (2) new acid addition salt of a 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one, where the acid used to form the acid addition salt is an organic acid, preferably 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one oxalate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one citrate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one acetate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one lactate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one malate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one malonate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one fumarate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one maleate, 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one tartrate and 4-(4-((5S))-5-(aminomethyl)-2-oxo-1,3-oxozoladine-3-yl)phenyl)morpholin-3-one formate; and    (3) a pharmaceutical composition (C1) comprising the rivaroxaban prepared according process (P1) or (P2) together with excipients or carriers.