* BASF could also move unit into joint venture

* Expects to close Ciba takeover at end of Q1

* Shares gain 8 percent

FRANKFURT, Feb 4 (Reuters) - Germany's BASF (BASF.DE) said on Wednesday it is considering selling its leather and textile chemicals business or transferring it into a joint venture as part of a wider overhaul.

The world's largest chemical company also announced structural changes in anticipation of an April 1 closure of its takeover of Swiss rival Ciba (CIBN.VX), in which it holds 94 percent.

BASF operates leather and textile chemical plants in Germany, Spain, Turkey, Brazil, India and China. The business, with about 1,300 staff, posted sales of about 400 million euros in 2007.

BASF said that, despite having restructured the business, it was no longer considered viable in the long term on a standalone basis. A sale would continue a trend.

Amid keen competition from Asia, BASF's German peers Lanxess (LXSG.DE) and buyout-firm-controlled Cognis divested their textile chemicals businesses in 2006 and 2008 respectively, while Switzerland's Clariant (CLN.VX) said last month prospects for its textile and leather operations were uncertain.

Shares in BASF rose 8.0 percent to 24.44 euros by 1501 GMT, outperforming a 3.8 percent gain in the European DJ Stoxx Chemicals Index .SX4P.

The company also said it would expand its Performance Products division, one of six, by adding a new paper chemicals unit as of April 1.

By then, BASF expects to have won regulatory approval to close the 3.4-billion-Swiss-franc acquisition of Ciba, which is the world's third-biggest supplier of paper chemicals.

Ciba is also the largest maker of additives for plastics. That business and its plastics and metals coatings operations would also be integrated into the Performance Products division.